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rl/Lib/site-packages/sympy/physics/vector/__init__.py

@@ -0,0 +1,36 @@
+__all__ = [
+    'CoordinateSym', 'ReferenceFrame',
+
+    'Dyadic',
+
+    'Vector',
+
+    'Point',
+
+    'cross', 'dot', 'express', 'time_derivative', 'outer',
+    'kinematic_equations', 'get_motion_params', 'partial_velocity',
+    'dynamicsymbols',
+
+    'vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting',
+
+    'curl', 'divergence', 'gradient', 'is_conservative', 'is_solenoidal',
+    'scalar_potential', 'scalar_potential_difference',
+
+]
+from .frame import CoordinateSym, ReferenceFrame
+
+from .dyadic import Dyadic
+
+from .vector import Vector
+
+from .point import Point
+
+from .functions import (cross, dot, express, time_derivative, outer,
+        kinematic_equations, get_motion_params, partial_velocity,
+        dynamicsymbols)
+
+from .printing import (vprint, vsstrrepr, vsprint, vpprint, vlatex,
+        init_vprinting)
+
+from .fieldfunctions import (curl, divergence, gradient, is_conservative,
+        is_solenoidal, scalar_potential, scalar_potential_difference)

rl/Lib/site-packages/sympy/physics/vector/dyadic.py

@@ -0,0 +1,545 @@
+from sympy import sympify, Add, ImmutableMatrix as Matrix
+from sympy.core.evalf import EvalfMixin
+from sympy.printing.defaults import Printable
+
+from mpmath.libmp.libmpf import prec_to_dps
+
+
+__all__ = ['Dyadic']
+
+
+class Dyadic(Printable, EvalfMixin):
+    """A Dyadic object.
+
+    See:
+    https://en.wikipedia.org/wiki/Dyadic_tensor
+    Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill
+
+    A more powerful way to represent a rigid body's inertia. While it is more
+    complex, by choosing Dyadic components to be in body fixed basis vectors,
+    the resulting matrix is equivalent to the inertia tensor.
+
+    """
+
+    is_number = False
+
+    def __init__(self, inlist):
+        """
+        Just like Vector's init, you should not call this unless creating a
+        zero dyadic.
+
+        zd = Dyadic(0)
+
+        Stores a Dyadic as a list of lists; the inner list has the measure
+        number and the two unit vectors; the outerlist holds each unique
+        unit vector pair.
+
+        """
+
+        self.args = []
+        if inlist == 0:
+            inlist = []
+        while len(inlist) != 0:
+            added = 0
+            for i, v in enumerate(self.args):
+                if ((str(inlist[0][1]) == str(self.args[i][1])) and
+                        (str(inlist[0][2]) == str(self.args[i][2]))):
+                    self.args[i] = (self.args[i][0] + inlist[0][0],
+                                    inlist[0][1], inlist[0][2])
+                    inlist.remove(inlist[0])
+                    added = 1
+                    break
+            if added != 1:
+                self.args.append(inlist[0])
+                inlist.remove(inlist[0])
+        i = 0
+        # This code is to remove empty parts from the list
+        while i < len(self.args):
+            if ((self.args[i][0] == 0) | (self.args[i][1] == 0) |
+                    (self.args[i][2] == 0)):
+                self.args.remove(self.args[i])
+                i -= 1
+            i += 1
+
+    @property
+    def func(self):
+        """Returns the class Dyadic. """
+        return Dyadic
+
+    def __add__(self, other):
+        """The add operator for Dyadic. """
+        other = _check_dyadic(other)
+        return Dyadic(self.args + other.args)
+
+    __radd__ = __add__
+
+    def __mul__(self, other):
+        """Multiplies the Dyadic by a sympifyable expression.
+
+        Parameters
+        ==========
+
+        other : Sympafiable
+            The scalar to multiply this Dyadic with
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, outer
+        >>> N = ReferenceFrame('N')
+        >>> d = outer(N.x, N.x)
+        >>> 5 * d
+        5*(N.x|N.x)
+
+        """
+        newlist = list(self.args)
+        other = sympify(other)
+        for i, v in enumerate(newlist):
+            newlist[i] = (other * newlist[i][0], newlist[i][1],
+                          newlist[i][2])
+        return Dyadic(newlist)
+
+    __rmul__ = __mul__
+
+    def dot(self, other):
+        """The inner product operator for a Dyadic and a Dyadic or Vector.
+
+        Parameters
+        ==========
+
+        other : Dyadic or Vector
+            The other Dyadic or Vector to take the inner product with
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, outer
+        >>> N = ReferenceFrame('N')
+        >>> D1 = outer(N.x, N.y)
+        >>> D2 = outer(N.y, N.y)
+        >>> D1.dot(D2)
+        (N.x|N.y)
+        >>> D1.dot(N.y)
+        N.x
+
+        """
+        from sympy.physics.vector.vector import Vector, _check_vector
+        if isinstance(other, Dyadic):
+            other = _check_dyadic(other)
+            ol = Dyadic(0)
+            for v in self.args:
+                for v2 in other.args:
+                    ol += v[0] * v2[0] * (v[2].dot(v2[1])) * (v[1].outer(v2[2]))
+        else:
+            other = _check_vector(other)
+            ol = Vector(0)
+            for v in self.args:
+                ol += v[0] * v[1] * (v[2].dot(other))
+        return ol
+
+    # NOTE : supports non-advertised Dyadic & Dyadic, Dyadic & Vector notation
+    __and__ = dot
+
+    def __truediv__(self, other):
+        """Divides the Dyadic by a sympifyable expression. """
+        return self.__mul__(1 / other)
+
+    def __eq__(self, other):
+        """Tests for equality.
+
+        Is currently weak; needs stronger comparison testing
+
+        """
+
+        if other == 0:
+            other = Dyadic(0)
+        other = _check_dyadic(other)
+        if (self.args == []) and (other.args == []):
+            return True
+        elif (self.args == []) or (other.args == []):
+            return False
+        return set(self.args) == set(other.args)
+
+    def __ne__(self, other):
+        return not self == other
+
+    def __neg__(self):
+        return self * -1
+
+    def _latex(self, printer):
+        ar = self.args  # just to shorten things
+        if len(ar) == 0:
+            return str(0)
+        ol = []  # output list, to be concatenated to a string
+        for i, v in enumerate(ar):
+            # if the coef of the dyadic is 1, we skip the 1
+            if ar[i][0] == 1:
+                ol.append(' + ' + printer._print(ar[i][1]) + r"\otimes " +
+                          printer._print(ar[i][2]))
+            # if the coef of the dyadic is -1, we skip the 1
+            elif ar[i][0] == -1:
+                ol.append(' - ' +
+                          printer._print(ar[i][1]) +
+                          r"\otimes " +
+                          printer._print(ar[i][2]))
+            # If the coefficient of the dyadic is not 1 or -1,
+            # we might wrap it in parentheses, for readability.
+            elif ar[i][0] != 0:
+                arg_str = printer._print(ar[i][0])
+                if isinstance(ar[i][0], Add):
+                    arg_str = '(%s)' % arg_str
+                if arg_str.startswith('-'):
+                    arg_str = arg_str[1:]
+                    str_start = ' - '
+                else:
+                    str_start = ' + '
+                ol.append(str_start + arg_str + printer._print(ar[i][1]) +
+                          r"\otimes " + printer._print(ar[i][2]))
+        outstr = ''.join(ol)
+        if outstr.startswith(' + '):
+            outstr = outstr[3:]
+        elif outstr.startswith(' '):
+            outstr = outstr[1:]
+        return outstr
+
+    def _pretty(self, printer):
+        e = self
+
+        class Fake:
+            baseline = 0
+
+            def render(self, *args, **kwargs):
+                ar = e.args  # just to shorten things
+                mpp = printer
+                if len(ar) == 0:
+                    return str(0)
+                bar = "\N{CIRCLED TIMES}" if printer._use_unicode else "|"
+                ol = []  # output list, to be concatenated to a string
+                for i, v in enumerate(ar):
+                    # if the coef of the dyadic is 1, we skip the 1
+                    if ar[i][0] == 1:
+                        ol.extend([" + ",
+                                  mpp.doprint(ar[i][1]),
+                                  bar,
+                                  mpp.doprint(ar[i][2])])
+
+                    # if the coef of the dyadic is -1, we skip the 1
+                    elif ar[i][0] == -1:
+                        ol.extend([" - ",
+                                  mpp.doprint(ar[i][1]),
+                                  bar,
+                                  mpp.doprint(ar[i][2])])
+
+                    # If the coefficient of the dyadic is not 1 or -1,
+                    # we might wrap it in parentheses, for readability.
+                    elif ar[i][0] != 0:
+                        if isinstance(ar[i][0], Add):
+                            arg_str = mpp._print(
+                                ar[i][0]).parens()[0]
+                        else:
+                            arg_str = mpp.doprint(ar[i][0])
+                        if arg_str.startswith("-"):
+                            arg_str = arg_str[1:]
+                            str_start = " - "
+                        else:
+                            str_start = " + "
+                        ol.extend([str_start, arg_str, " ",
+                                  mpp.doprint(ar[i][1]),
+                                  bar,
+                                  mpp.doprint(ar[i][2])])
+
+                outstr = "".join(ol)
+                if outstr.startswith(" + "):
+                    outstr = outstr[3:]
+                elif outstr.startswith(" "):
+                    outstr = outstr[1:]
+                return outstr
+        return Fake()
+
+    def __rsub__(self, other):
+        return (-1 * self) + other
+
+    def _sympystr(self, printer):
+        """Printing method. """
+        ar = self.args  # just to shorten things
+        if len(ar) == 0:
+            return printer._print(0)
+        ol = []  # output list, to be concatenated to a string
+        for i, v in enumerate(ar):
+            # if the coef of the dyadic is 1, we skip the 1
+            if ar[i][0] == 1:
+                ol.append(' + (' + printer._print(ar[i][1]) + '|' +
+                          printer._print(ar[i][2]) + ')')
+            # if the coef of the dyadic is -1, we skip the 1
+            elif ar[i][0] == -1:
+                ol.append(' - (' + printer._print(ar[i][1]) + '|' +
+                          printer._print(ar[i][2]) + ')')
+            # If the coefficient of the dyadic is not 1 or -1,
+            # we might wrap it in parentheses, for readability.
+            elif ar[i][0] != 0:
+                arg_str = printer._print(ar[i][0])
+                if isinstance(ar[i][0], Add):
+                    arg_str = "(%s)" % arg_str
+                if arg_str[0] == '-':
+                    arg_str = arg_str[1:]
+                    str_start = ' - '
+                else:
+                    str_start = ' + '
+                ol.append(str_start + arg_str + '*(' +
+                          printer._print(ar[i][1]) +
+                          '|' + printer._print(ar[i][2]) + ')')
+        outstr = ''.join(ol)
+        if outstr.startswith(' + '):
+            outstr = outstr[3:]
+        elif outstr.startswith(' '):
+            outstr = outstr[1:]
+        return outstr
+
+    def __sub__(self, other):
+        """The subtraction operator. """
+        return self.__add__(other * -1)
+
+    def cross(self, other):
+        """Returns the dyadic resulting from the dyadic vector cross product:
+        Dyadic x Vector.
+
+        Parameters
+        ==========
+        other : Vector
+            Vector to cross with.
+
+        Examples
+        ========
+        >>> from sympy.physics.vector import ReferenceFrame, outer, cross
+        >>> N = ReferenceFrame('N')
+        >>> d = outer(N.x, N.x)
+        >>> cross(d, N.y)
+        (N.x|N.z)
+
+        """
+        from sympy.physics.vector.vector import _check_vector
+        other = _check_vector(other)
+        ol = Dyadic(0)
+        for v in self.args:
+            ol += v[0] * (v[1].outer((v[2].cross(other))))
+        return ol
+
+    # NOTE : supports non-advertised Dyadic ^ Vector notation
+    __xor__ = cross
+
+    def express(self, frame1, frame2=None):
+        """Expresses this Dyadic in alternate frame(s)
+
+        The first frame is the list side expression, the second frame is the
+        right side; if Dyadic is in form A.x|B.y, you can express it in two
+        different frames. If no second frame is given, the Dyadic is
+        expressed in only one frame.
+
+        Calls the global express function
+
+        Parameters
+        ==========
+
+        frame1 : ReferenceFrame
+            The frame to express the left side of the Dyadic in
+        frame2 : ReferenceFrame
+            If provided, the frame to express the right side of the Dyadic in
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> N = ReferenceFrame('N')
+        >>> q = dynamicsymbols('q')
+        >>> B = N.orientnew('B', 'Axis', [q, N.z])
+        >>> d = outer(N.x, N.x)
+        >>> d.express(B, N)
+        cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x)
+
+        """
+        from sympy.physics.vector.functions import express
+        return express(self, frame1, frame2)
+
+    def to_matrix(self, reference_frame, second_reference_frame=None):
+        """Returns the matrix form of the dyadic with respect to one or two
+        reference frames.
+
+        Parameters
+        ----------
+        reference_frame : ReferenceFrame
+            The reference frame that the rows and columns of the matrix
+            correspond to. If a second reference frame is provided, this
+            only corresponds to the rows of the matrix.
+        second_reference_frame : ReferenceFrame, optional, default=None
+            The reference frame that the columns of the matrix correspond
+            to.
+
+        Returns
+        -------
+        matrix : ImmutableMatrix, shape(3,3)
+            The matrix that gives the 2D tensor form.
+
+        Examples
+        ========
+
+        >>> from sympy import symbols, trigsimp
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> from sympy.physics.mechanics import inertia
+        >>> Ixx, Iyy, Izz, Ixy, Iyz, Ixz = symbols('Ixx, Iyy, Izz, Ixy, Iyz, Ixz')
+        >>> N = ReferenceFrame('N')
+        >>> inertia_dyadic = inertia(N, Ixx, Iyy, Izz, Ixy, Iyz, Ixz)
+        >>> inertia_dyadic.to_matrix(N)
+        Matrix([
+        [Ixx, Ixy, Ixz],
+        [Ixy, Iyy, Iyz],
+        [Ixz, Iyz, Izz]])
+        >>> beta = symbols('beta')
+        >>> A = N.orientnew('A', 'Axis', (beta, N.x))
+        >>> trigsimp(inertia_dyadic.to_matrix(A))
+        Matrix([
+        [                           Ixx,                                           Ixy*cos(beta) + Ixz*sin(beta),                                           -Ixy*sin(beta) + Ixz*cos(beta)],
+        [ Ixy*cos(beta) + Ixz*sin(beta), Iyy*cos(2*beta)/2 + Iyy/2 + Iyz*sin(2*beta) - Izz*cos(2*beta)/2 + Izz/2,                 -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2],
+        [-Ixy*sin(beta) + Ixz*cos(beta),                -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2, -Iyy*cos(2*beta)/2 + Iyy/2 - Iyz*sin(2*beta) + Izz*cos(2*beta)/2 + Izz/2]])
+
+        """
+
+        if second_reference_frame is None:
+            second_reference_frame = reference_frame
+
+        return Matrix([i.dot(self).dot(j) for i in reference_frame for j in
+                      second_reference_frame]).reshape(3, 3)
+
+    def doit(self, **hints):
+        """Calls .doit() on each term in the Dyadic"""
+        return sum([Dyadic([(v[0].doit(**hints), v[1], v[2])])
+                    for v in self.args], Dyadic(0))
+
+    def dt(self, frame):
+        """Take the time derivative of this Dyadic in a frame.
+
+        This function calls the global time_derivative method
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame to take the time derivative in
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> N = ReferenceFrame('N')
+        >>> q = dynamicsymbols('q')
+        >>> B = N.orientnew('B', 'Axis', [q, N.z])
+        >>> d = outer(N.x, N.x)
+        >>> d.dt(B)
+        - q'*(N.y|N.x) - q'*(N.x|N.y)
+
+        """
+        from sympy.physics.vector.functions import time_derivative
+        return time_derivative(self, frame)
+
+    def simplify(self):
+        """Returns a simplified Dyadic."""
+        out = Dyadic(0)
+        for v in self.args:
+            out += Dyadic([(v[0].simplify(), v[1], v[2])])
+        return out
+
+    def subs(self, *args, **kwargs):
+        """Substitution on the Dyadic.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> from sympy import Symbol
+        >>> N = ReferenceFrame('N')
+        >>> s = Symbol('s')
+        >>> a = s*(N.x|N.x)
+        >>> a.subs({s: 2})
+        2*(N.x|N.x)
+
+        """
+
+        return sum([Dyadic([(v[0].subs(*args, **kwargs), v[1], v[2])])
+                    for v in self.args], Dyadic(0))
+
+    def applyfunc(self, f):
+        """Apply a function to each component of a Dyadic."""
+        if not callable(f):
+            raise TypeError("`f` must be callable.")
+
+        out = Dyadic(0)
+        for a, b, c in self.args:
+            out += f(a) * (b.outer(c))
+        return out
+
+    def _eval_evalf(self, prec):
+        if not self.args:
+            return self
+        new_args = []
+        dps = prec_to_dps(prec)
+        for inlist in self.args:
+            new_inlist = list(inlist)
+            new_inlist[0] = inlist[0].evalf(n=dps)
+            new_args.append(tuple(new_inlist))
+        return Dyadic(new_args)
+
+    def xreplace(self, rule):
+        """
+        Replace occurrences of objects within the measure numbers of the
+        Dyadic.
+
+        Parameters
+        ==========
+
+        rule : dict-like
+            Expresses a replacement rule.
+
+        Returns
+        =======
+
+        Dyadic
+            Result of the replacement.
+
+        Examples
+        ========
+
+        >>> from sympy import symbols, pi
+        >>> from sympy.physics.vector import ReferenceFrame, outer
+        >>> N = ReferenceFrame('N')
+        >>> D = outer(N.x, N.x)
+        >>> x, y, z = symbols('x y z')
+        >>> ((1 + x*y) * D).xreplace({x: pi})
+        (pi*y + 1)*(N.x|N.x)
+        >>> ((1 + x*y) * D).xreplace({x: pi, y: 2})
+        (1 + 2*pi)*(N.x|N.x)
+
+        Replacements occur only if an entire node in the expression tree is
+        matched:
+
+        >>> ((x*y + z) * D).xreplace({x*y: pi})
+        (z + pi)*(N.x|N.x)
+        >>> ((x*y*z) * D).xreplace({x*y: pi})
+        x*y*z*(N.x|N.x)
+
+        """
+
+        new_args = []
+        for inlist in self.args:
+            new_inlist = list(inlist)
+            new_inlist[0] = new_inlist[0].xreplace(rule)
+            new_args.append(tuple(new_inlist))
+        return Dyadic(new_args)
+
+
+def _check_dyadic(other):
+    if not isinstance(other, Dyadic):
+        raise TypeError('A Dyadic must be supplied')
+    return other

rl/Lib/site-packages/sympy/physics/vector/fieldfunctions.py

@@ -0,0 +1,313 @@
+from sympy.core.function import diff
+from sympy.core.singleton import S
+from sympy.integrals.integrals import integrate
+from sympy.physics.vector import Vector, express
+from sympy.physics.vector.frame import _check_frame
+from sympy.physics.vector.vector import _check_vector
+
+
+__all__ = ['curl', 'divergence', 'gradient', 'is_conservative',
+           'is_solenoidal', 'scalar_potential',
+           'scalar_potential_difference']
+
+
+def curl(vect, frame):
+    """
+    Returns the curl of a vector field computed wrt the coordinate
+    symbols of the given frame.
+
+    Parameters
+    ==========
+
+    vect : Vector
+        The vector operand
+
+    frame : ReferenceFrame
+        The reference frame to calculate the curl in
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import curl
+    >>> R = ReferenceFrame('R')
+    >>> v1 = R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z
+    >>> curl(v1, R)
+    0
+    >>> v2 = R[0]*R[1]*R[2]*R.x
+    >>> curl(v2, R)
+    R_x*R_y*R.y - R_x*R_z*R.z
+
+    """
+
+    _check_vector(vect)
+    if vect == 0:
+        return Vector(0)
+    vect = express(vect, frame, variables=True)
+    # A mechanical approach to avoid looping overheads
+    vectx = vect.dot(frame.x)
+    vecty = vect.dot(frame.y)
+    vectz = vect.dot(frame.z)
+    outvec = Vector(0)
+    outvec += (diff(vectz, frame[1]) - diff(vecty, frame[2])) * frame.x
+    outvec += (diff(vectx, frame[2]) - diff(vectz, frame[0])) * frame.y
+    outvec += (diff(vecty, frame[0]) - diff(vectx, frame[1])) * frame.z
+    return outvec
+
+
+def divergence(vect, frame):
+    """
+    Returns the divergence of a vector field computed wrt the coordinate
+    symbols of the given frame.
+
+    Parameters
+    ==========
+
+    vect : Vector
+        The vector operand
+
+    frame : ReferenceFrame
+        The reference frame to calculate the divergence in
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import divergence
+    >>> R = ReferenceFrame('R')
+    >>> v1 = R[0]*R[1]*R[2] * (R.x+R.y+R.z)
+    >>> divergence(v1, R)
+    R_x*R_y + R_x*R_z + R_y*R_z
+    >>> v2 = 2*R[1]*R[2]*R.y
+    >>> divergence(v2, R)
+    2*R_z
+
+    """
+
+    _check_vector(vect)
+    if vect == 0:
+        return S.Zero
+    vect = express(vect, frame, variables=True)
+    vectx = vect.dot(frame.x)
+    vecty = vect.dot(frame.y)
+    vectz = vect.dot(frame.z)
+    out = S.Zero
+    out += diff(vectx, frame[0])
+    out += diff(vecty, frame[1])
+    out += diff(vectz, frame[2])
+    return out
+
+
+def gradient(scalar, frame):
+    """
+    Returns the vector gradient of a scalar field computed wrt the
+    coordinate symbols of the given frame.
+
+    Parameters
+    ==========
+
+    scalar : sympifiable
+        The scalar field to take the gradient of
+
+    frame : ReferenceFrame
+        The frame to calculate the gradient in
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import gradient
+    >>> R = ReferenceFrame('R')
+    >>> s1 = R[0]*R[1]*R[2]
+    >>> gradient(s1, R)
+    R_y*R_z*R.x + R_x*R_z*R.y + R_x*R_y*R.z
+    >>> s2 = 5*R[0]**2*R[2]
+    >>> gradient(s2, R)
+    10*R_x*R_z*R.x + 5*R_x**2*R.z
+
+    """
+
+    _check_frame(frame)
+    outvec = Vector(0)
+    scalar = express(scalar, frame, variables=True)
+    for i, x in enumerate(frame):
+        outvec += diff(scalar, frame[i]) * x
+    return outvec
+
+
+def is_conservative(field):
+    """
+    Checks if a field is conservative.
+
+    Parameters
+    ==========
+
+    field : Vector
+        The field to check for conservative property
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import is_conservative
+    >>> R = ReferenceFrame('R')
+    >>> is_conservative(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z)
+    True
+    >>> is_conservative(R[2] * R.y)
+    False
+
+    """
+
+    # Field is conservative irrespective of frame
+    # Take the first frame in the result of the separate method of Vector
+    if field == Vector(0):
+        return True
+    frame = list(field.separate())[0]
+    return curl(field, frame).simplify() == Vector(0)
+
+
+def is_solenoidal(field):
+    """
+    Checks if a field is solenoidal.
+
+    Parameters
+    ==========
+
+    field : Vector
+        The field to check for solenoidal property
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import is_solenoidal
+    >>> R = ReferenceFrame('R')
+    >>> is_solenoidal(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z)
+    True
+    >>> is_solenoidal(R[1] * R.y)
+    False
+
+    """
+
+    # Field is solenoidal irrespective of frame
+    # Take the first frame in the result of the separate method in Vector
+    if field == Vector(0):
+        return True
+    frame = list(field.separate())[0]
+    return divergence(field, frame).simplify() is S.Zero
+
+
+def scalar_potential(field, frame):
+    """
+    Returns the scalar potential function of a field in a given frame
+    (without the added integration constant).
+
+    Parameters
+    ==========
+
+    field : Vector
+        The vector field whose scalar potential function is to be
+        calculated
+
+    frame : ReferenceFrame
+        The frame to do the calculation in
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame
+    >>> from sympy.physics.vector import scalar_potential, gradient
+    >>> R = ReferenceFrame('R')
+    >>> scalar_potential(R.z, R) == R[2]
+    True
+    >>> scalar_field = 2*R[0]**2*R[1]*R[2]
+    >>> grad_field = gradient(scalar_field, R)
+    >>> scalar_potential(grad_field, R)
+    2*R_x**2*R_y*R_z
+
+    """
+
+    # Check whether field is conservative
+    if not is_conservative(field):
+        raise ValueError("Field is not conservative")
+    if field == Vector(0):
+        return S.Zero
+    # Express the field exntirely in frame
+    # Substitute coordinate variables also
+    _check_frame(frame)
+    field = express(field, frame, variables=True)
+    # Make a list of dimensions of the frame
+    dimensions = list(frame)
+    # Calculate scalar potential function
+    temp_function = integrate(field.dot(dimensions[0]), frame[0])
+    for i, dim in enumerate(dimensions[1:]):
+        partial_diff = diff(temp_function, frame[i + 1])
+        partial_diff = field.dot(dim) - partial_diff
+        temp_function += integrate(partial_diff, frame[i + 1])
+    return temp_function
+
+
+def scalar_potential_difference(field, frame, point1, point2, origin):
+    """
+    Returns the scalar potential difference between two points in a
+    certain frame, wrt a given field.
+
+    If a scalar field is provided, its values at the two points are
+    considered. If a conservative vector field is provided, the values
+    of its scalar potential function at the two points are used.
+
+    Returns (potential at position 2) - (potential at position 1)
+
+    Parameters
+    ==========
+
+    field : Vector/sympyfiable
+        The field to calculate wrt
+
+    frame : ReferenceFrame
+        The frame to do the calculations in
+
+    point1 : Point
+        The initial Point in given frame
+
+    position2 : Point
+        The second Point in the given frame
+
+    origin : Point
+        The Point to use as reference point for position vector
+        calculation
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame, Point
+    >>> from sympy.physics.vector import scalar_potential_difference
+    >>> R = ReferenceFrame('R')
+    >>> O = Point('O')
+    >>> P = O.locatenew('P', R[0]*R.x + R[1]*R.y + R[2]*R.z)
+    >>> vectfield = 4*R[0]*R[1]*R.x + 2*R[0]**2*R.y
+    >>> scalar_potential_difference(vectfield, R, O, P, O)
+    2*R_x**2*R_y
+    >>> Q = O.locatenew('O', 3*R.x + R.y + 2*R.z)
+    >>> scalar_potential_difference(vectfield, R, P, Q, O)
+    -2*R_x**2*R_y + 18
+
+    """
+
+    _check_frame(frame)
+    if isinstance(field, Vector):
+        # Get the scalar potential function
+        scalar_fn = scalar_potential(field, frame)
+    else:
+        # Field is a scalar
+        scalar_fn = field
+    # Express positions in required frame
+    position1 = express(point1.pos_from(origin), frame, variables=True)
+    position2 = express(point2.pos_from(origin), frame, variables=True)
+    # Get the two positions as substitution dicts for coordinate variables
+    subs_dict1 = {}
+    subs_dict2 = {}
+    for i, x in enumerate(frame):
+        subs_dict1[frame[i]] = x.dot(position1)
+        subs_dict2[frame[i]] = x.dot(position2)
+    return scalar_fn.subs(subs_dict2) - scalar_fn.subs(subs_dict1)

rl/Lib/site-packages/sympy/physics/vector/functions.py

@@ -0,0 +1,650 @@
+from functools import reduce
+
+from sympy import (sympify, diff, sin, cos, Matrix, symbols,
+                                Function, S, Symbol, linear_eq_to_matrix)
+from sympy.integrals.integrals import integrate
+from sympy.simplify.trigsimp import trigsimp
+from .vector import Vector, _check_vector
+from .frame import CoordinateSym, _check_frame
+from .dyadic import Dyadic
+from .printing import vprint, vsprint, vpprint, vlatex, init_vprinting
+from sympy.utilities.iterables import iterable
+from sympy.utilities.misc import translate
+
+__all__ = ['cross', 'dot', 'express', 'time_derivative', 'outer',
+           'kinematic_equations', 'get_motion_params', 'partial_velocity',
+           'dynamicsymbols', 'vprint', 'vsprint', 'vpprint', 'vlatex',
+           'init_vprinting']
+
+
+def cross(vec1, vec2):
+    """Cross product convenience wrapper for Vector.cross(): \n"""
+    if not isinstance(vec1, (Vector, Dyadic)):
+        raise TypeError('Cross product is between two vectors')
+    return vec1 ^ vec2
+
+
+cross.__doc__ += Vector.cross.__doc__  # type: ignore
+
+
+def dot(vec1, vec2):
+    """Dot product convenience wrapper for Vector.dot(): \n"""
+    if not isinstance(vec1, (Vector, Dyadic)):
+        raise TypeError('Dot product is between two vectors')
+    return vec1 & vec2
+
+
+dot.__doc__ += Vector.dot.__doc__  # type: ignore
+
+
+def express(expr, frame, frame2=None, variables=False):
+    """
+    Global function for 'express' functionality.
+
+    Re-expresses a Vector, scalar(sympyfiable) or Dyadic in given frame.
+
+    Refer to the local methods of Vector and Dyadic for details.
+    If 'variables' is True, then the coordinate variables (CoordinateSym
+    instances) of other frames present in the vector/scalar field or
+    dyadic expression are also substituted in terms of the base scalars of
+    this frame.
+
+    Parameters
+    ==========
+
+    expr : Vector/Dyadic/scalar(sympyfiable)
+        The expression to re-express in ReferenceFrame 'frame'
+
+    frame: ReferenceFrame
+        The reference frame to express expr in
+
+    frame2 : ReferenceFrame
+        The other frame required for re-expression(only for Dyadic expr)
+
+    variables : boolean
+        Specifies whether to substitute the coordinate variables present
+        in expr, in terms of those of frame
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> N = ReferenceFrame('N')
+    >>> q = dynamicsymbols('q')
+    >>> B = N.orientnew('B', 'Axis', [q, N.z])
+    >>> d = outer(N.x, N.x)
+    >>> from sympy.physics.vector import express
+    >>> express(d, B, N)
+    cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x)
+    >>> express(B.x, N)
+    cos(q)*N.x + sin(q)*N.y
+    >>> express(N[0], B, variables=True)
+    B_x*cos(q) - B_y*sin(q)
+
+    """
+
+    _check_frame(frame)
+
+    if expr == 0:
+        return expr
+
+    if isinstance(expr, Vector):
+        # Given expr is a Vector
+        if variables:
+            # If variables attribute is True, substitute the coordinate
+            # variables in the Vector
+            frame_list = [x[-1] for x in expr.args]
+            subs_dict = {}
+            for f in frame_list:
+                subs_dict.update(f.variable_map(frame))
+            expr = expr.subs(subs_dict)
+        # Re-express in this frame
+        outvec = Vector([])
+        for v in expr.args:
+            if v[1] != frame:
+                temp = frame.dcm(v[1]) * v[0]
+                if Vector.simp:
+                    temp = temp.applyfunc(lambda x:
+                                          trigsimp(x, method='fu'))
+                outvec += Vector([(temp, frame)])
+            else:
+                outvec += Vector([v])
+        return outvec
+
+    if isinstance(expr, Dyadic):
+        if frame2 is None:
+            frame2 = frame
+        _check_frame(frame2)
+        ol = Dyadic(0)
+        for v in expr.args:
+            ol += express(v[0], frame, variables=variables) * \
+                  (express(v[1], frame, variables=variables) |
+                   express(v[2], frame2, variables=variables))
+        return ol
+
+    else:
+        if variables:
+            # Given expr is a scalar field
+            frame_set = set()
+            expr = sympify(expr)
+            # Substitute all the coordinate variables
+            for x in expr.free_symbols:
+                if isinstance(x, CoordinateSym) and x.frame != frame:
+                    frame_set.add(x.frame)
+            subs_dict = {}
+            for f in frame_set:
+                subs_dict.update(f.variable_map(frame))
+            return expr.subs(subs_dict)
+        return expr
+
+
+def time_derivative(expr, frame, order=1):
+    """
+    Calculate the time derivative of a vector/scalar field function
+    or dyadic expression in given frame.
+
+    References
+    ==========
+
+    https://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames
+
+    Parameters
+    ==========
+
+    expr : Vector/Dyadic/sympifyable
+        The expression whose time derivative is to be calculated
+
+    frame : ReferenceFrame
+        The reference frame to calculate the time derivative in
+
+    order : integer
+        The order of the derivative to be calculated
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> from sympy import Symbol
+    >>> q1 = Symbol('q1')
+    >>> u1 = dynamicsymbols('u1')
+    >>> N = ReferenceFrame('N')
+    >>> A = N.orientnew('A', 'Axis', [q1, N.x])
+    >>> v = u1 * N.x
+    >>> A.set_ang_vel(N, 10*A.x)
+    >>> from sympy.physics.vector import time_derivative
+    >>> time_derivative(v, N)
+    u1'*N.x
+    >>> time_derivative(u1*A[0], N)
+    N_x*u1'
+    >>> B = N.orientnew('B', 'Axis', [u1, N.z])
+    >>> from sympy.physics.vector import outer
+    >>> d = outer(N.x, N.x)
+    >>> time_derivative(d, B)
+    - u1'*(N.y|N.x) - u1'*(N.x|N.y)
+
+    """
+
+    t = dynamicsymbols._t
+    _check_frame(frame)
+
+    if order == 0:
+        return expr
+    if order % 1 != 0 or order < 0:
+        raise ValueError("Unsupported value of order entered")
+
+    if isinstance(expr, Vector):
+        outlist = []
+        for v in expr.args:
+            if v[1] == frame:
+                outlist += [(express(v[0], frame, variables=True).diff(t),
+                             frame)]
+            else:
+                outlist += (time_derivative(Vector([v]), v[1]) +
+                            (v[1].ang_vel_in(frame) ^ Vector([v]))).args
+        outvec = Vector(outlist)
+        return time_derivative(outvec, frame, order - 1)
+
+    if isinstance(expr, Dyadic):
+        ol = Dyadic(0)
+        for v in expr.args:
+            ol += (v[0].diff(t) * (v[1] | v[2]))
+            ol += (v[0] * (time_derivative(v[1], frame) | v[2]))
+            ol += (v[0] * (v[1] | time_derivative(v[2], frame)))
+        return time_derivative(ol, frame, order - 1)
+
+    else:
+        return diff(express(expr, frame, variables=True), t, order)
+
+
+def outer(vec1, vec2):
+    """Outer product convenience wrapper for Vector.outer():\n"""
+    if not isinstance(vec1, Vector):
+        raise TypeError('Outer product is between two Vectors')
+    return vec1.outer(vec2)
+
+
+outer.__doc__ += Vector.outer.__doc__  # type: ignore
+
+
+def kinematic_equations(speeds, coords, rot_type, rot_order=''):
+    """Gives equations relating the qdot's to u's for a rotation type.
+
+    Supply rotation type and order as in orient. Speeds are assumed to be
+    body-fixed; if we are defining the orientation of B in A using by rot_type,
+    the angular velocity of B in A is assumed to be in the form: speed[0]*B.x +
+    speed[1]*B.y + speed[2]*B.z
+
+    Parameters
+    ==========
+
+    speeds : list of length 3
+        The body fixed angular velocity measure numbers.
+    coords : list of length 3 or 4
+        The coordinates used to define the orientation of the two frames.
+    rot_type : str
+        The type of rotation used to create the equations. Body, Space, or
+        Quaternion only
+    rot_order : str or int
+        If applicable, the order of a series of rotations.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> from sympy.physics.vector import kinematic_equations, vprint
+    >>> u1, u2, u3 = dynamicsymbols('u1 u2 u3')
+    >>> q1, q2, q3 = dynamicsymbols('q1 q2 q3')
+    >>> vprint(kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', '313'),
+    ...     order=None)
+    [-(u1*sin(q3) + u2*cos(q3))/sin(q2) + q1', -u1*cos(q3) + u2*sin(q3) + q2', (u1*sin(q3) + u2*cos(q3))*cos(q2)/sin(q2) - u3 + q3']
+
+    """
+
+    # Code below is checking and sanitizing input
+    approved_orders = ('123', '231', '312', '132', '213', '321', '121', '131',
+                       '212', '232', '313', '323', '1', '2', '3', '')
+    # make sure XYZ => 123 and rot_type is in lower case
+    rot_order = translate(str(rot_order), 'XYZxyz', '123123')
+    rot_type = rot_type.lower()
+
+    if not isinstance(speeds, (list, tuple)):
+        raise TypeError('Need to supply speeds in a list')
+    if len(speeds) != 3:
+        raise TypeError('Need to supply 3 body-fixed speeds')
+    if not isinstance(coords, (list, tuple)):
+        raise TypeError('Need to supply coordinates in a list')
+    if rot_type in ['body', 'space']:
+        if rot_order not in approved_orders:
+            raise ValueError('Not an acceptable rotation order')
+        if len(coords) != 3:
+            raise ValueError('Need 3 coordinates for body or space')
+        # Actual hard-coded kinematic differential equations
+        w1, w2, w3 = speeds
+        if w1 == w2 == w3 == 0:
+            return [S.Zero]*3
+        q1, q2, q3 = coords
+        q1d, q2d, q3d = [diff(i, dynamicsymbols._t) for i in coords]
+        s1, s2, s3 = [sin(q1), sin(q2), sin(q3)]
+        c1, c2, c3 = [cos(q1), cos(q2), cos(q3)]
+        if rot_type == 'body':
+            if rot_order == '123':
+                return [q1d - (w1 * c3 - w2 * s3) / c2, q2d - w1 * s3 - w2 *
+                        c3, q3d - (-w1 * c3 + w2 * s3) * s2 / c2 - w3]
+            if rot_order == '231':
+                return [q1d - (w2 * c3 - w3 * s3) / c2, q2d - w2 * s3 - w3 *
+                        c3, q3d - w1 - (- w2 * c3 + w3 * s3) * s2 / c2]
+            if rot_order == '312':
+                return [q1d - (-w1 * s3 + w3 * c3) / c2, q2d - w1 * c3 - w3 *
+                        s3, q3d - (w1 * s3 - w3 * c3) * s2 / c2 - w2]
+            if rot_order == '132':
+                return [q1d - (w1 * c3 + w3 * s3) / c2, q2d + w1 * s3 - w3 *
+                        c3, q3d - (w1 * c3 + w3 * s3) * s2 / c2 - w2]
+            if rot_order == '213':
+                return [q1d - (w1 * s3 + w2 * c3) / c2, q2d - w1 * c3 + w2 *
+                        s3, q3d - (w1 * s3 + w2 * c3) * s2 / c2 - w3]
+            if rot_order == '321':
+                return [q1d - (w2 * s3 + w3 * c3) / c2, q2d - w2 * c3 + w3 *
+                        s3, q3d - w1 - (w2 * s3 + w3 * c3) * s2 / c2]
+            if rot_order == '121':
+                return [q1d - (w2 * s3 + w3 * c3) / s2, q2d - w2 * c3 + w3 *
+                        s3, q3d - w1 + (w2 * s3 + w3 * c3) * c2 / s2]
+            if rot_order == '131':
+                return [q1d - (-w2 * c3 + w3 * s3) / s2, q2d - w2 * s3 - w3 *
+                        c3, q3d - w1 - (w2 * c3 - w3 * s3) * c2 / s2]
+            if rot_order == '212':
+                return [q1d - (w1 * s3 - w3 * c3) / s2, q2d - w1 * c3 - w3 *
+                        s3, q3d - (-w1 * s3 + w3 * c3) * c2 / s2 - w2]
+            if rot_order == '232':
+                return [q1d - (w1 * c3 + w3 * s3) / s2, q2d + w1 * s3 - w3 *
+                        c3, q3d + (w1 * c3 + w3 * s3) * c2 / s2 - w2]
+            if rot_order == '313':
+                return [q1d - (w1 * s3 + w2 * c3) / s2, q2d - w1 * c3 + w2 *
+                        s3, q3d + (w1 * s3 + w2 * c3) * c2 / s2 - w3]
+            if rot_order == '323':
+                return [q1d - (-w1 * c3 + w2 * s3) / s2, q2d - w1 * s3 - w2 *
+                        c3, q3d - (w1 * c3 - w2 * s3) * c2 / s2 - w3]
+        if rot_type == 'space':
+            if rot_order == '123':
+                return [q1d - w1 - (w2 * s1 + w3 * c1) * s2 / c2, q2d - w2 *
+                        c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / c2]
+            if rot_order == '231':
+                return [q1d - (w1 * c1 + w3 * s1) * s2 / c2 - w2, q2d + w1 *
+                        s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / c2]
+            if rot_order == '312':
+                return [q1d - (w1 * s1 + w2 * c1) * s2 / c2 - w3, q2d - w1 *
+                        c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / c2]
+            if rot_order == '132':
+                return [q1d - w1 - (-w2 * c1 + w3 * s1) * s2 / c2, q2d - w2 *
+                        s1 - w3 * c1, q3d - (w2 * c1 - w3 * s1) / c2]
+            if rot_order == '213':
+                return [q1d - (w1 * s1 - w3 * c1) * s2 / c2 - w2, q2d - w1 *
+                        c1 - w3 * s1, q3d - (-w1 * s1 + w3 * c1) / c2]
+            if rot_order == '321':
+                return [q1d - (-w1 * c1 + w2 * s1) * s2 / c2 - w3, q2d - w1 *
+                        s1 - w2 * c1, q3d - (w1 * c1 - w2 * s1) / c2]
+            if rot_order == '121':
+                return [q1d - w1 + (w2 * s1 + w3 * c1) * c2 / s2, q2d - w2 *
+                        c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / s2]
+            if rot_order == '131':
+                return [q1d - w1 - (w2 * c1 - w3 * s1) * c2 / s2, q2d - w2 *
+                        s1 - w3 * c1, q3d - (-w2 * c1 + w3 * s1) / s2]
+            if rot_order == '212':
+                return [q1d - (-w1 * s1 + w3 * c1) * c2 / s2 - w2, q2d - w1 *
+                        c1 - w3 * s1, q3d - (w1 * s1 - w3 * c1) / s2]
+            if rot_order == '232':
+                return [q1d + (w1 * c1 + w3 * s1) * c2 / s2 - w2, q2d + w1 *
+                        s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / s2]
+            if rot_order == '313':
+                return [q1d + (w1 * s1 + w2 * c1) * c2 / s2 - w3, q2d - w1 *
+                        c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / s2]
+            if rot_order == '323':
+                return [q1d - (w1 * c1 - w2 * s1) * c2 / s2 - w3, q2d - w1 *
+                        s1 - w2 * c1, q3d - (-w1 * c1 + w2 * s1) / s2]
+    elif rot_type == 'quaternion':
+        if rot_order != '':
+            raise ValueError('Cannot have rotation order for quaternion')
+        if len(coords) != 4:
+            raise ValueError('Need 4 coordinates for quaternion')
+        # Actual hard-coded kinematic differential equations
+        e0, e1, e2, e3 = coords
+        w = Matrix(speeds + [0])
+        E = Matrix([[e0, -e3, e2, e1],
+                    [e3, e0, -e1, e2],
+                    [-e2, e1, e0, e3],
+                    [-e1, -e2, -e3, e0]])
+        edots = Matrix([diff(i, dynamicsymbols._t) for i in [e1, e2, e3, e0]])
+        return list(edots.T - 0.5 * w.T * E.T)
+    else:
+        raise ValueError('Not an approved rotation type for this function')
+
+
+def get_motion_params(frame, **kwargs):
+    """
+    Returns the three motion parameters - (acceleration, velocity, and
+    position) as vectorial functions of time in the given frame.
+
+    If a higher order differential function is provided, the lower order
+    functions are used as boundary conditions. For example, given the
+    acceleration, the velocity and position parameters are taken as
+    boundary conditions.
+
+    The values of time at which the boundary conditions are specified
+    are taken from timevalue1(for position boundary condition) and
+    timevalue2(for velocity boundary condition).
+
+    If any of the boundary conditions are not provided, they are taken
+    to be zero by default (zero vectors, in case of vectorial inputs). If
+    the boundary conditions are also functions of time, they are converted
+    to constants by substituting the time values in the dynamicsymbols._t
+    time Symbol.
+
+    This function can also be used for calculating rotational motion
+    parameters. Have a look at the Parameters and Examples for more clarity.
+
+    Parameters
+    ==========
+
+    frame : ReferenceFrame
+        The frame to express the motion parameters in
+
+    acceleration : Vector
+        Acceleration of the object/frame as a function of time
+
+    velocity : Vector
+        Velocity as function of time or as boundary condition
+        of velocity at time = timevalue1
+
+    position : Vector
+        Velocity as function of time or as boundary condition
+        of velocity at time = timevalue1
+
+    timevalue1 : sympyfiable
+        Value of time for position boundary condition
+
+    timevalue2 : sympyfiable
+        Value of time for velocity boundary condition
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import ReferenceFrame, get_motion_params, dynamicsymbols
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> from sympy import symbols
+    >>> R = ReferenceFrame('R')
+    >>> v1, v2, v3 = dynamicsymbols('v1 v2 v3')
+    >>> v = v1*R.x + v2*R.y + v3*R.z
+    >>> get_motion_params(R, position = v)
+    (v1''*R.x + v2''*R.y + v3''*R.z, v1'*R.x + v2'*R.y + v3'*R.z, v1*R.x + v2*R.y + v3*R.z)
+    >>> a, b, c = symbols('a b c')
+    >>> v = a*R.x + b*R.y + c*R.z
+    >>> get_motion_params(R, velocity = v)
+    (0, a*R.x + b*R.y + c*R.z, a*t*R.x + b*t*R.y + c*t*R.z)
+    >>> parameters = get_motion_params(R, acceleration = v)
+    >>> parameters[1]
+    a*t*R.x + b*t*R.y + c*t*R.z
+    >>> parameters[2]
+    a*t**2/2*R.x + b*t**2/2*R.y + c*t**2/2*R.z
+
+    """
+
+    def _process_vector_differential(vectdiff, condition, variable, ordinate,
+                                     frame):
+        """
+        Helper function for get_motion methods. Finds derivative of vectdiff
+        wrt variable, and its integral using the specified boundary condition
+        at value of variable = ordinate.
+        Returns a tuple of - (derivative, function and integral) wrt vectdiff
+
+        """
+
+        # Make sure boundary condition is independent of 'variable'
+        if condition != 0:
+            condition = express(condition, frame, variables=True)
+        # Special case of vectdiff == 0
+        if vectdiff == Vector(0):
+            return (0, 0, condition)
+        # Express vectdiff completely in condition's frame to give vectdiff1
+        vectdiff1 = express(vectdiff, frame)
+        # Find derivative of vectdiff
+        vectdiff2 = time_derivative(vectdiff, frame)
+        # Integrate and use boundary condition
+        vectdiff0 = Vector(0)
+        lims = (variable, ordinate, variable)
+        for dim in frame:
+            function1 = vectdiff1.dot(dim)
+            abscissa = dim.dot(condition).subs({variable: ordinate})
+            # Indefinite integral of 'function1' wrt 'variable', using
+            # the given initial condition (ordinate, abscissa).
+            vectdiff0 += (integrate(function1, lims) + abscissa) * dim
+        # Return tuple
+        return (vectdiff2, vectdiff, vectdiff0)
+
+    _check_frame(frame)
+    # Decide mode of operation based on user's input
+    if 'acceleration' in kwargs:
+        mode = 2
+    elif 'velocity' in kwargs:
+        mode = 1
+    else:
+        mode = 0
+    # All the possible parameters in kwargs
+    # Not all are required for every case
+    # If not specified, set to default values(may or may not be used in
+    # calculations)
+    conditions = ['acceleration', 'velocity', 'position',
+                  'timevalue', 'timevalue1', 'timevalue2']
+    for i, x in enumerate(conditions):
+        if x not in kwargs:
+            if i < 3:
+                kwargs[x] = Vector(0)
+            else:
+                kwargs[x] = S.Zero
+        elif i < 3:
+            _check_vector(kwargs[x])
+        else:
+            kwargs[x] = sympify(kwargs[x])
+    if mode == 2:
+        vel = _process_vector_differential(kwargs['acceleration'],
+                                           kwargs['velocity'],
+                                           dynamicsymbols._t,
+                                           kwargs['timevalue2'], frame)[2]
+        pos = _process_vector_differential(vel, kwargs['position'],
+                                           dynamicsymbols._t,
+                                           kwargs['timevalue1'], frame)[2]
+        return (kwargs['acceleration'], vel, pos)
+    elif mode == 1:
+        return _process_vector_differential(kwargs['velocity'],
+                                            kwargs['position'],
+                                            dynamicsymbols._t,
+                                            kwargs['timevalue1'], frame)
+    else:
+        vel = time_derivative(kwargs['position'], frame)
+        acc = time_derivative(vel, frame)
+        return (acc, vel, kwargs['position'])
+
+
+def partial_velocity(vel_vecs, gen_speeds, frame):
+    """Returns a list of partial velocities with respect to the provided
+    generalized speeds in the given reference frame for each of the supplied
+    velocity vectors.
+
+    The output is a list of lists. The outer list has a number of elements
+    equal to the number of supplied velocity vectors. The inner lists are, for
+    each velocity vector, the partial derivatives of that velocity vector with
+    respect to the generalized speeds supplied.
+
+    Parameters
+    ==========
+
+    vel_vecs : iterable
+        An iterable of velocity vectors (angular or linear).
+    gen_speeds : iterable
+        An iterable of generalized speeds.
+    frame : ReferenceFrame
+        The reference frame that the partial derivatives are going to be taken
+        in.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import Point, ReferenceFrame
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> from sympy.physics.vector import partial_velocity
+    >>> u = dynamicsymbols('u')
+    >>> N = ReferenceFrame('N')
+    >>> P = Point('P')
+    >>> P.set_vel(N, u * N.x)
+    >>> vel_vecs = [P.vel(N)]
+    >>> gen_speeds = [u]
+    >>> partial_velocity(vel_vecs, gen_speeds, N)
+    [[N.x]]
+
+    """
+
+    if not iterable(vel_vecs):
+        raise TypeError('Velocity vectors must be contained in an iterable.')
+
+    if not iterable(gen_speeds):
+        raise TypeError('Generalized speeds must be contained in an iterable')
+
+    vec_partials = []
+    gen_speeds = list(gen_speeds)
+    for vel in vel_vecs:
+        partials = [Vector(0) for _ in gen_speeds]
+        for components, ref in vel.args:
+            mat, _ = linear_eq_to_matrix(components, gen_speeds)
+            for i in range(len(gen_speeds)):
+                for dim, direction in enumerate(ref):
+                    if mat[dim, i] != 0:
+                        partials[i] += direction * mat[dim, i]
+
+        vec_partials.append(partials)
+
+    return vec_partials
+
+
+def dynamicsymbols(names, level=0, **assumptions):
+    """Uses symbols and Function for functions of time.
+
+    Creates a SymPy UndefinedFunction, which is then initialized as a function
+    of a variable, the default being Symbol('t').
+
+    Parameters
+    ==========
+
+    names : str
+        Names of the dynamic symbols you want to create; works the same way as
+        inputs to symbols
+    level : int
+        Level of differentiation of the returned function; d/dt once of t,
+        twice of t, etc.
+    assumptions :
+        - real(bool) : This is used to set the dynamicsymbol as real,
+                    by default is False.
+        - positive(bool) : This is used to set the dynamicsymbol as positive,
+                    by default is False.
+        - commutative(bool) : This is used to set the commutative property of
+                    a dynamicsymbol, by default is True.
+        - integer(bool) : This is used to set the dynamicsymbol as integer,
+                    by default is False.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import dynamicsymbols
+    >>> from sympy import diff, Symbol
+    >>> q1 = dynamicsymbols('q1')
+    >>> q1
+    q1(t)
+    >>> q2 = dynamicsymbols('q2', real=True)
+    >>> q2.is_real
+    True
+    >>> q3 = dynamicsymbols('q3', positive=True)
+    >>> q3.is_positive
+    True
+    >>> q4, q5 = dynamicsymbols('q4,q5', commutative=False)
+    >>> bool(q4*q5 != q5*q4)
+    True
+    >>> q6 = dynamicsymbols('q6', integer=True)
+    >>> q6.is_integer
+    True
+    >>> diff(q1, Symbol('t'))
+    Derivative(q1(t), t)
+
+    """
+    esses = symbols(names, cls=Function, **assumptions)
+    t = dynamicsymbols._t
+    if iterable(esses):
+        esses = [reduce(diff, [t] * level, e(t)) for e in esses]
+        return esses
+    else:
+        return reduce(diff, [t] * level, esses(t))
+
+
+dynamicsymbols._t = Symbol('t')  # type: ignore
+dynamicsymbols._str = '\''  # type: ignore

rl/Lib/site-packages/sympy/physics/vector/point.py

@@ -0,0 +1,635 @@
+from .vector import Vector, _check_vector
+from .frame import _check_frame
+from warnings import warn
+from sympy.utilities.misc import filldedent
+
+__all__ = ['Point']
+
+
+class Point:
+    """This object represents a point in a dynamic system.
+
+    It stores the: position, velocity, and acceleration of a point.
+    The position is a vector defined as the vector distance from a parent
+    point to this point.
+
+    Parameters
+    ==========
+
+    name : string
+        The display name of the Point
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> N = ReferenceFrame('N')
+    >>> O = Point('O')
+    >>> P = Point('P')
+    >>> u1, u2, u3 = dynamicsymbols('u1 u2 u3')
+    >>> O.set_vel(N, u1 * N.x + u2 * N.y + u3 * N.z)
+    >>> O.acc(N)
+    u1'*N.x + u2'*N.y + u3'*N.z
+
+    ``symbols()`` can be used to create multiple Points in a single step, for
+    example:
+
+    >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> from sympy import symbols
+    >>> N = ReferenceFrame('N')
+    >>> u1, u2 = dynamicsymbols('u1 u2')
+    >>> A, B = symbols('A B', cls=Point)
+    >>> type(A)
+    <class 'sympy.physics.vector.point.Point'>
+    >>> A.set_vel(N, u1 * N.x + u2 * N.y)
+    >>> B.set_vel(N, u2 * N.x + u1 * N.y)
+    >>> A.acc(N) - B.acc(N)
+    (u1' - u2')*N.x + (-u1' + u2')*N.y
+
+    """
+
+    def __init__(self, name):
+        """Initialization of a Point object. """
+        self.name = name
+        self._pos_dict = {}
+        self._vel_dict = {}
+        self._acc_dict = {}
+        self._pdlist = [self._pos_dict, self._vel_dict, self._acc_dict]
+
+    def __str__(self):
+        return self.name
+
+    __repr__ = __str__
+
+    def _check_point(self, other):
+        if not isinstance(other, Point):
+            raise TypeError('A Point must be supplied')
+
+    def _pdict_list(self, other, num):
+        """Returns a list of points that gives the shortest path with respect
+        to position, velocity, or acceleration from this point to the provided
+        point.
+
+        Parameters
+        ==========
+        other : Point
+            A point that may be related to this point by position, velocity, or
+            acceleration.
+        num : integer
+            0 for searching the position tree, 1 for searching the velocity
+            tree, and 2 for searching the acceleration tree.
+
+        Returns
+        =======
+        list of Points
+            A sequence of points from self to other.
+
+        Notes
+        =====
+
+        It is not clear if num = 1 or num = 2 actually works because the keys
+        to ``_vel_dict`` and ``_acc_dict`` are :class:`ReferenceFrame` objects
+        which do not have the ``_pdlist`` attribute.
+
+        """
+        outlist = [[self]]
+        oldlist = [[]]
+        while outlist != oldlist:
+            oldlist = outlist[:]
+            for v in outlist:
+                templist = v[-1]._pdlist[num].keys()
+                for v2 in templist:
+                    if not v.__contains__(v2):
+                        littletemplist = v + [v2]
+                        if not outlist.__contains__(littletemplist):
+                            outlist.append(littletemplist)
+        for v in oldlist:
+            if v[-1] != other:
+                outlist.remove(v)
+        outlist.sort(key=len)
+        if len(outlist) != 0:
+            return outlist[0]
+        raise ValueError('No Connecting Path found between ' + other.name +
+                         ' and ' + self.name)
+
+    def a1pt_theory(self, otherpoint, outframe, interframe):
+        """Sets the acceleration of this point with the 1-point theory.
+
+        The 1-point theory for point acceleration looks like this:
+
+        ^N a^P = ^B a^P + ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B
+        x r^OP) + 2 ^N omega^B x ^B v^P
+
+        where O is a point fixed in B, P is a point moving in B, and B is
+        rotating in frame N.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The first point of the 1-point theory (O)
+        outframe : ReferenceFrame
+            The frame we want this point's acceleration defined in (N)
+        fixedframe : ReferenceFrame
+            The intermediate frame in this calculation (B)
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> q = dynamicsymbols('q')
+        >>> q2 = dynamicsymbols('q2')
+        >>> qd = dynamicsymbols('q', 1)
+        >>> q2d = dynamicsymbols('q2', 1)
+        >>> N = ReferenceFrame('N')
+        >>> B = ReferenceFrame('B')
+        >>> B.set_ang_vel(N, 5 * B.y)
+        >>> O = Point('O')
+        >>> P = O.locatenew('P', q * B.x + q2 * B.y)
+        >>> P.set_vel(B, qd * B.x + q2d * B.y)
+        >>> O.set_vel(N, 0)
+        >>> P.a1pt_theory(O, N, B)
+        (-25*q + q'')*B.x + q2''*B.y - 10*q'*B.z
+
+        """
+
+        _check_frame(outframe)
+        _check_frame(interframe)
+        self._check_point(otherpoint)
+        dist = self.pos_from(otherpoint)
+        v = self.vel(interframe)
+        a1 = otherpoint.acc(outframe)
+        a2 = self.acc(interframe)
+        omega = interframe.ang_vel_in(outframe)
+        alpha = interframe.ang_acc_in(outframe)
+        self.set_acc(outframe, a2 + 2 * (omega.cross(v)) + a1 +
+                     (alpha.cross(dist)) + (omega.cross(omega.cross(dist))))
+        return self.acc(outframe)
+
+    def a2pt_theory(self, otherpoint, outframe, fixedframe):
+        """Sets the acceleration of this point with the 2-point theory.
+
+        The 2-point theory for point acceleration looks like this:
+
+        ^N a^P = ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B x r^OP)
+
+        where O and P are both points fixed in frame B, which is rotating in
+        frame N.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The first point of the 2-point theory (O)
+        outframe : ReferenceFrame
+            The frame we want this point's acceleration defined in (N)
+        fixedframe : ReferenceFrame
+            The frame in which both points are fixed (B)
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> q = dynamicsymbols('q')
+        >>> qd = dynamicsymbols('q', 1)
+        >>> N = ReferenceFrame('N')
+        >>> B = N.orientnew('B', 'Axis', [q, N.z])
+        >>> O = Point('O')
+        >>> P = O.locatenew('P', 10 * B.x)
+        >>> O.set_vel(N, 5 * N.x)
+        >>> P.a2pt_theory(O, N, B)
+        - 10*q'**2*B.x + 10*q''*B.y
+
+        """
+
+        _check_frame(outframe)
+        _check_frame(fixedframe)
+        self._check_point(otherpoint)
+        dist = self.pos_from(otherpoint)
+        a = otherpoint.acc(outframe)
+        omega = fixedframe.ang_vel_in(outframe)
+        alpha = fixedframe.ang_acc_in(outframe)
+        self.set_acc(outframe, a + (alpha.cross(dist)) +
+                     (omega.cross(omega.cross(dist))))
+        return self.acc(outframe)
+
+    def acc(self, frame):
+        """The acceleration Vector of this Point in a ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which the returned acceleration vector will be defined
+            in.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p1.set_acc(N, 10 * N.x)
+        >>> p1.acc(N)
+        10*N.x
+
+        """
+
+        _check_frame(frame)
+        if not (frame in self._acc_dict):
+            if self.vel(frame) != 0:
+                return (self._vel_dict[frame]).dt(frame)
+            else:
+                return Vector(0)
+        return self._acc_dict[frame]
+
+    def locatenew(self, name, value):
+        """Creates a new point with a position defined from this point.
+
+        Parameters
+        ==========
+
+        name : str
+            The name for the new point
+        value : Vector
+            The position of the new point relative to this point
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, Point
+        >>> N = ReferenceFrame('N')
+        >>> P1 = Point('P1')
+        >>> P2 = P1.locatenew('P2', 10 * N.x)
+
+        """
+
+        if not isinstance(name, str):
+            raise TypeError('Must supply a valid name')
+        if value == 0:
+            value = Vector(0)
+        value = _check_vector(value)
+        p = Point(name)
+        p.set_pos(self, value)
+        self.set_pos(p, -value)
+        return p
+
+    def pos_from(self, otherpoint):
+        """Returns a Vector distance between this Point and the other Point.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The otherpoint we are locating this one relative to
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p2 = Point('p2')
+        >>> p1.set_pos(p2, 10 * N.x)
+        >>> p1.pos_from(p2)
+        10*N.x
+
+        """
+
+        outvec = Vector(0)
+        plist = self._pdict_list(otherpoint, 0)
+        for i in range(len(plist) - 1):
+            outvec += plist[i]._pos_dict[plist[i + 1]]
+        return outvec
+
+    def set_acc(self, frame, value):
+        """Used to set the acceleration of this Point in a ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which this point's acceleration is defined
+        value : Vector
+            The vector value of this point's acceleration in the frame
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p1.set_acc(N, 10 * N.x)
+        >>> p1.acc(N)
+        10*N.x
+
+        """
+
+        if value == 0:
+            value = Vector(0)
+        value = _check_vector(value)
+        _check_frame(frame)
+        self._acc_dict.update({frame: value})
+
+    def set_pos(self, otherpoint, value):
+        """Used to set the position of this point w.r.t. another point.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The other point which this point's location is defined relative to
+        value : Vector
+            The vector which defines the location of this point
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p2 = Point('p2')
+        >>> p1.set_pos(p2, 10 * N.x)
+        >>> p1.pos_from(p2)
+        10*N.x
+
+        """
+
+        if value == 0:
+            value = Vector(0)
+        value = _check_vector(value)
+        self._check_point(otherpoint)
+        self._pos_dict.update({otherpoint: value})
+        otherpoint._pos_dict.update({self: -value})
+
+    def set_vel(self, frame, value):
+        """Sets the velocity Vector of this Point in a ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which this point's velocity is defined
+        value : Vector
+            The vector value of this point's velocity in the frame
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p1.set_vel(N, 10 * N.x)
+        >>> p1.vel(N)
+        10*N.x
+
+        """
+
+        if value == 0:
+            value = Vector(0)
+        value = _check_vector(value)
+        _check_frame(frame)
+        self._vel_dict.update({frame: value})
+
+    def v1pt_theory(self, otherpoint, outframe, interframe):
+        """Sets the velocity of this point with the 1-point theory.
+
+        The 1-point theory for point velocity looks like this:
+
+        ^N v^P = ^B v^P + ^N v^O + ^N omega^B x r^OP
+
+        where O is a point fixed in B, P is a point moving in B, and B is
+        rotating in frame N.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The first point of the 1-point theory (O)
+        outframe : ReferenceFrame
+            The frame we want this point's velocity defined in (N)
+        interframe : ReferenceFrame
+            The intermediate frame in this calculation (B)
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> q = dynamicsymbols('q')
+        >>> q2 = dynamicsymbols('q2')
+        >>> qd = dynamicsymbols('q', 1)
+        >>> q2d = dynamicsymbols('q2', 1)
+        >>> N = ReferenceFrame('N')
+        >>> B = ReferenceFrame('B')
+        >>> B.set_ang_vel(N, 5 * B.y)
+        >>> O = Point('O')
+        >>> P = O.locatenew('P', q * B.x + q2 * B.y)
+        >>> P.set_vel(B, qd * B.x + q2d * B.y)
+        >>> O.set_vel(N, 0)
+        >>> P.v1pt_theory(O, N, B)
+        q'*B.x + q2'*B.y - 5*q*B.z
+
+        """
+
+        _check_frame(outframe)
+        _check_frame(interframe)
+        self._check_point(otherpoint)
+        dist = self.pos_from(otherpoint)
+        v1 = self.vel(interframe)
+        v2 = otherpoint.vel(outframe)
+        omega = interframe.ang_vel_in(outframe)
+        self.set_vel(outframe, v1 + v2 + (omega.cross(dist)))
+        return self.vel(outframe)
+
+    def v2pt_theory(self, otherpoint, outframe, fixedframe):
+        """Sets the velocity of this point with the 2-point theory.
+
+        The 2-point theory for point velocity looks like this:
+
+        ^N v^P = ^N v^O + ^N omega^B x r^OP
+
+        where O and P are both points fixed in frame B, which is rotating in
+        frame N.
+
+        Parameters
+        ==========
+
+        otherpoint : Point
+            The first point of the 2-point theory (O)
+        outframe : ReferenceFrame
+            The frame we want this point's velocity defined in (N)
+        fixedframe : ReferenceFrame
+            The frame in which both points are fixed (B)
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> q = dynamicsymbols('q')
+        >>> qd = dynamicsymbols('q', 1)
+        >>> N = ReferenceFrame('N')
+        >>> B = N.orientnew('B', 'Axis', [q, N.z])
+        >>> O = Point('O')
+        >>> P = O.locatenew('P', 10 * B.x)
+        >>> O.set_vel(N, 5 * N.x)
+        >>> P.v2pt_theory(O, N, B)
+        5*N.x + 10*q'*B.y
+
+        """
+
+        _check_frame(outframe)
+        _check_frame(fixedframe)
+        self._check_point(otherpoint)
+        dist = self.pos_from(otherpoint)
+        v = otherpoint.vel(outframe)
+        omega = fixedframe.ang_vel_in(outframe)
+        self.set_vel(outframe, v + (omega.cross(dist)))
+        return self.vel(outframe)
+
+    def vel(self, frame):
+        """The velocity Vector of this Point in the ReferenceFrame.
+
+        Parameters
+        ==========
+
+        frame : ReferenceFrame
+            The frame in which the returned velocity vector will be defined in
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
+        >>> N = ReferenceFrame('N')
+        >>> p1 = Point('p1')
+        >>> p1.set_vel(N, 10 * N.x)
+        >>> p1.vel(N)
+        10*N.x
+
+        Velocities will be automatically calculated if possible, otherwise a
+        ``ValueError`` will be returned. If it is possible to calculate
+        multiple different velocities from the relative points, the points
+        defined most directly relative to this point will be used. In the case
+        of inconsistent relative positions of points, incorrect velocities may
+        be returned. It is up to the user to define prior relative positions
+        and velocities of points in a self-consistent way.
+
+        >>> p = Point('p')
+        >>> q = dynamicsymbols('q')
+        >>> p.set_vel(N, 10 * N.x)
+        >>> p2 = Point('p2')
+        >>> p2.set_pos(p, q*N.x)
+        >>> p2.vel(N)
+        (Derivative(q(t), t) + 10)*N.x
+
+        """
+
+        _check_frame(frame)
+        if not (frame in self._vel_dict):
+            valid_neighbor_found = False
+            is_cyclic = False
+            visited = []
+            queue = [self]
+            candidate_neighbor = []
+            while queue:  # BFS to find nearest point
+                node = queue.pop(0)
+                if node not in visited:
+                    visited.append(node)
+                    for neighbor, neighbor_pos in node._pos_dict.items():
+                        if neighbor in visited:
+                            continue
+                        try:
+                            # Checks if pos vector is valid
+                            neighbor_pos.express(frame)
+                        except ValueError:
+                            continue
+                        if neighbor in queue:
+                            is_cyclic = True
+                        try:
+                            # Checks if point has its vel defined in req frame
+                            neighbor_velocity = neighbor._vel_dict[frame]
+                        except KeyError:
+                            queue.append(neighbor)
+                            continue
+                        candidate_neighbor.append(neighbor)
+                        if not valid_neighbor_found:
+                            self.set_vel(frame, self.pos_from(neighbor).dt(frame) + neighbor_velocity)
+                            valid_neighbor_found = True
+            if is_cyclic:
+                warn(filldedent("""
+                Kinematic loops are defined among the positions of points. This
+                is likely not desired and may cause errors in your calculations.
+                """))
+            if len(candidate_neighbor) > 1:
+                warn(filldedent(f"""
+                Velocity of {self.name} automatically calculated based on point
+                {candidate_neighbor[0].name} but it is also possible from
+                points(s): {str(candidate_neighbor[1:])}. Velocities from these
+                points are not necessarily the same. This may cause errors in
+                your calculations."""))
+            if valid_neighbor_found:
+                return self._vel_dict[frame]
+            else:
+                raise ValueError(filldedent(f"""
+                Velocity of point {self.name} has not been defined in
+                ReferenceFrame {frame.name}."""))
+
+        return self._vel_dict[frame]
+
+    def partial_velocity(self, frame, *gen_speeds):
+        """Returns the partial velocities of the linear velocity vector of this
+        point in the given frame with respect to one or more provided
+        generalized speeds.
+
+        Parameters
+        ==========
+        frame : ReferenceFrame
+            The frame with which the velocity is defined in.
+        gen_speeds : functions of time
+            The generalized speeds.
+
+        Returns
+        =======
+        partial_velocities : tuple of Vector
+            The partial velocity vectors corresponding to the provided
+            generalized speeds.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, Point
+        >>> from sympy.physics.vector import dynamicsymbols
+        >>> N = ReferenceFrame('N')
+        >>> A = ReferenceFrame('A')
+        >>> p = Point('p')
+        >>> u1, u2 = dynamicsymbols('u1, u2')
+        >>> p.set_vel(N, u1 * N.x + u2 * A.y)
+        >>> p.partial_velocity(N, u1)
+        N.x
+        >>> p.partial_velocity(N, u1, u2)
+        (N.x, A.y)
+
+        """
+
+        from sympy.physics.vector.functions import partial_velocity
+
+        vel = self.vel(frame)
+        partials = partial_velocity([vel], gen_speeds, frame)[0]
+
+        if len(partials) == 1:
+            return partials[0]
+        else:
+            return tuple(partials)

rl/Lib/site-packages/sympy/physics/vector/printing.py

@@ -0,0 +1,371 @@
+from sympy.core.function import Derivative
+from sympy.core.function import UndefinedFunction, AppliedUndef
+from sympy.core.symbol import Symbol
+from sympy.interactive.printing import init_printing
+from sympy.printing.latex import LatexPrinter
+from sympy.printing.pretty.pretty import PrettyPrinter
+from sympy.printing.pretty.pretty_symbology import center_accent
+from sympy.printing.str import StrPrinter
+from sympy.printing.precedence import PRECEDENCE
+
+__all__ = ['vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex',
+           'init_vprinting']
+
+
+class VectorStrPrinter(StrPrinter):
+    """String Printer for vector expressions. """
+
+    def _print_Derivative(self, e):
+        from sympy.physics.vector.functions import dynamicsymbols
+        t = dynamicsymbols._t
+        if (bool(sum(i == t for i in e.variables)) &
+                isinstance(type(e.args[0]), UndefinedFunction)):
+            ol = str(e.args[0].func)
+            for i, v in enumerate(e.variables):
+                ol += dynamicsymbols._str
+            return ol
+        else:
+            return StrPrinter().doprint(e)
+
+    def _print_Function(self, e):
+        from sympy.physics.vector.functions import dynamicsymbols
+        t = dynamicsymbols._t
+        if isinstance(type(e), UndefinedFunction):
+            return StrPrinter().doprint(e).replace("(%s)" % t, '')
+        return e.func.__name__ + "(%s)" % self.stringify(e.args, ", ")
+
+
+class VectorStrReprPrinter(VectorStrPrinter):
+    """String repr printer for vector expressions."""
+    def _print_str(self, s):
+        return repr(s)
+
+
+class VectorLatexPrinter(LatexPrinter):
+    """Latex Printer for vector expressions. """
+
+    def _print_Function(self, expr, exp=None):
+        from sympy.physics.vector.functions import dynamicsymbols
+        func = expr.func.__name__
+        t = dynamicsymbols._t
+
+        if (hasattr(self, '_print_' + func) and not
+            isinstance(type(expr), UndefinedFunction)):
+            return getattr(self, '_print_' + func)(expr, exp)
+        elif isinstance(type(expr), UndefinedFunction) and (expr.args == (t,)):
+            # treat this function like a symbol
+            expr = Symbol(func)
+            if exp is not None:
+                # copied from LatexPrinter._helper_print_standard_power, which
+                # we can't call because we only have exp as a string.
+                base = self.parenthesize(expr, PRECEDENCE['Pow'])
+                base = self.parenthesize_super(base)
+                return r"%s^{%s}" % (base, exp)
+            else:
+                return super()._print(expr)
+        else:
+            return super()._print_Function(expr, exp)
+
+    def _print_Derivative(self, der_expr):
+        from sympy.physics.vector.functions import dynamicsymbols
+        # make sure it is in the right form
+        der_expr = der_expr.doit()
+        if not isinstance(der_expr, Derivative):
+            return r"\left(%s\right)" % self.doprint(der_expr)
+
+        # check if expr is a dynamicsymbol
+        t = dynamicsymbols._t
+        expr = der_expr.expr
+        red = expr.atoms(AppliedUndef)
+        syms = der_expr.variables
+        test1 = not all(True for i in red if i.free_symbols == {t})
+        test2 = not all(t == i for i in syms)
+        if test1 or test2:
+            return super()._print_Derivative(der_expr)
+
+        # done checking
+        dots = len(syms)
+        base = self._print_Function(expr)
+        base_split = base.split('_', 1)
+        base = base_split[0]
+        if dots == 1:
+            base = r"\dot{%s}" % base
+        elif dots == 2:
+            base = r"\ddot{%s}" % base
+        elif dots == 3:
+            base = r"\dddot{%s}" % base
+        elif dots == 4:
+            base = r"\ddddot{%s}" % base
+        else:  # Fallback to standard printing
+            return super()._print_Derivative(der_expr)
+        if len(base_split) != 1:
+            base += '_' + base_split[1]
+        return base
+
+
+class VectorPrettyPrinter(PrettyPrinter):
+    """Pretty Printer for vectorialexpressions. """
+
+    def _print_Derivative(self, deriv):
+        from sympy.physics.vector.functions import dynamicsymbols
+        # XXX use U('PARTIAL DIFFERENTIAL') here ?
+        t = dynamicsymbols._t
+        dot_i = 0
+        syms = list(reversed(deriv.variables))
+
+        while len(syms) > 0:
+            if syms[-1] == t:
+                syms.pop()
+                dot_i += 1
+            else:
+                return super()._print_Derivative(deriv)
+
+        if not (isinstance(type(deriv.expr), UndefinedFunction) and
+                (deriv.expr.args == (t,))):
+            return super()._print_Derivative(deriv)
+        else:
+            pform = self._print_Function(deriv.expr)
+
+        # the following condition would happen with some sort of non-standard
+        # dynamic symbol I guess, so we'll just print the SymPy way
+        if len(pform.picture) > 1:
+            return super()._print_Derivative(deriv)
+
+        # There are only special symbols up to fourth-order derivatives
+        if dot_i >= 5:
+            return super()._print_Derivative(deriv)
+
+        # Deal with special symbols
+        dots = {0: "",
+                1: "\N{COMBINING DOT ABOVE}",
+                2: "\N{COMBINING DIAERESIS}",
+                3: "\N{COMBINING THREE DOTS ABOVE}",
+                4: "\N{COMBINING FOUR DOTS ABOVE}"}
+
+        d = pform.__dict__
+        # if unicode is false then calculate number of apostrophes needed and
+        # add to output
+        if not self._use_unicode:
+            apostrophes = ""
+            for i in range(0, dot_i):
+                apostrophes += "'"
+            d['picture'][0] += apostrophes + "(t)"
+        else:
+            d['picture'] = [center_accent(d['picture'][0], dots[dot_i])]
+        return pform
+
+    def _print_Function(self, e):
+        from sympy.physics.vector.functions import dynamicsymbols
+        t = dynamicsymbols._t
+        # XXX works only for applied functions
+        func = e.func
+        args = e.args
+        func_name = func.__name__
+        pform = self._print_Symbol(Symbol(func_name))
+        # If this function is an Undefined function of t, it is probably a
+        # dynamic symbol, so we'll skip the (t). The rest of the code is
+        # identical to the normal PrettyPrinter code
+        if not (isinstance(func, UndefinedFunction) and (args == (t,))):
+            return super()._print_Function(e)
+        return pform
+
+
+def vprint(expr, **settings):
+    r"""Function for printing of expressions generated in the
+    sympy.physics vector package.
+
+    Extends SymPy's StrPrinter, takes the same setting accepted by SymPy's
+    :func:`~.sstr`, and is equivalent to ``print(sstr(foo))``.
+
+    Parameters
+    ==========
+
+    expr : valid SymPy object
+        SymPy expression to print.
+    settings : args
+        Same as the settings accepted by SymPy's sstr().
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import vprint, dynamicsymbols
+    >>> u1 = dynamicsymbols('u1')
+    >>> print(u1)
+    u1(t)
+    >>> vprint(u1)
+    u1
+
+    """
+
+    outstr = vsprint(expr, **settings)
+
+    import builtins
+    if (outstr != 'None'):
+        builtins._ = outstr
+        print(outstr)
+
+
+def vsstrrepr(expr, **settings):
+    """Function for displaying expression representation's with vector
+    printing enabled.
+
+    Parameters
+    ==========
+
+    expr : valid SymPy object
+        SymPy expression to print.
+    settings : args
+        Same as the settings accepted by SymPy's sstrrepr().
+
+    """
+    p = VectorStrReprPrinter(settings)
+    return p.doprint(expr)
+
+
+def vsprint(expr, **settings):
+    r"""Function for displaying expressions generated in the
+    sympy.physics vector package.
+
+    Returns the output of vprint() as a string.
+
+    Parameters
+    ==========
+
+    expr : valid SymPy object
+        SymPy expression to print
+    settings : args
+        Same as the settings accepted by SymPy's sstr().
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import vsprint, dynamicsymbols
+    >>> u1, u2 = dynamicsymbols('u1 u2')
+    >>> u2d = dynamicsymbols('u2', level=1)
+    >>> print("%s = %s" % (u1, u2 + u2d))
+    u1(t) = u2(t) + Derivative(u2(t), t)
+    >>> print("%s = %s" % (vsprint(u1), vsprint(u2 + u2d)))
+    u1 = u2 + u2'
+
+    """
+
+    string_printer = VectorStrPrinter(settings)
+    return string_printer.doprint(expr)
+
+
+def vpprint(expr, **settings):
+    r"""Function for pretty printing of expressions generated in the
+    sympy.physics vector package.
+
+    Mainly used for expressions not inside a vector; the output of running
+    scripts and generating equations of motion. Takes the same options as
+    SymPy's :func:`~.pretty_print`; see that function for more information.
+
+    Parameters
+    ==========
+
+    expr : valid SymPy object
+        SymPy expression to pretty print
+    settings : args
+        Same as those accepted by SymPy's pretty_print.
+
+
+    """
+
+    pp = VectorPrettyPrinter(settings)
+
+    # Note that this is copied from sympy.printing.pretty.pretty_print:
+
+    # XXX: this is an ugly hack, but at least it works
+    use_unicode = pp._settings['use_unicode']
+    from sympy.printing.pretty.pretty_symbology import pretty_use_unicode
+    uflag = pretty_use_unicode(use_unicode)
+
+    try:
+        return pp.doprint(expr)
+    finally:
+        pretty_use_unicode(uflag)
+
+
+def vlatex(expr, **settings):
+    r"""Function for printing latex representation of sympy.physics.vector
+    objects.
+
+    For latex representation of Vectors, Dyadics, and dynamicsymbols. Takes the
+    same options as SymPy's :func:`~.latex`; see that function for more
+    information;
+
+    Parameters
+    ==========
+
+    expr : valid SymPy object
+        SymPy expression to represent in LaTeX form
+    settings : args
+        Same as latex()
+
+    Examples
+    ========
+
+    >>> from sympy.physics.vector import vlatex, ReferenceFrame, dynamicsymbols
+    >>> N = ReferenceFrame('N')
+    >>> q1, q2 = dynamicsymbols('q1 q2')
+    >>> q1d, q2d = dynamicsymbols('q1 q2', 1)
+    >>> q1dd, q2dd = dynamicsymbols('q1 q2', 2)
+    >>> vlatex(N.x + N.y)
+    '\\mathbf{\\hat{n}_x} + \\mathbf{\\hat{n}_y}'
+    >>> vlatex(q1 + q2)
+    'q_{1} + q_{2}'
+    >>> vlatex(q1d)
+    '\\dot{q}_{1}'
+    >>> vlatex(q1 * q2d)
+    'q_{1} \\dot{q}_{2}'
+    >>> vlatex(q1dd * q1 / q1d)
+    '\\frac{q_{1} \\ddot{q}_{1}}{\\dot{q}_{1}}'
+
+    """
+    latex_printer = VectorLatexPrinter(settings)
+
+    return latex_printer.doprint(expr)
+
+
+def init_vprinting(**kwargs):
+    """Initializes time derivative printing for all SymPy objects, i.e. any
+    functions of time will be displayed in a more compact notation. The main
+    benefit of this is for printing of time derivatives; instead of
+    displaying as ``Derivative(f(t),t)``, it will display ``f'``. This is
+    only actually needed for when derivatives are present and are not in a
+    physics.vector.Vector or physics.vector.Dyadic object. This function is a
+    light wrapper to :func:`~.init_printing`. Any keyword
+    arguments for it are valid here.
+
+    {0}
+
+    Examples
+    ========
+
+    >>> from sympy import Function, symbols
+    >>> t, x = symbols('t, x')
+    >>> omega = Function('omega')
+    >>> omega(x).diff()
+    Derivative(omega(x), x)
+    >>> omega(t).diff()
+    Derivative(omega(t), t)
+
+    Now use the string printer:
+
+    >>> from sympy.physics.vector import init_vprinting
+    >>> init_vprinting(pretty_print=False)
+    >>> omega(x).diff()
+    Derivative(omega(x), x)
+    >>> omega(t).diff()
+    omega'
+
+    """
+    kwargs['str_printer'] = vsstrrepr
+    kwargs['pretty_printer'] = vpprint
+    kwargs['latex_printer'] = vlatex
+    init_printing(**kwargs)
+
+
+params = init_printing.__doc__.split('Examples\n    ========')[0]  # type: ignore
+init_vprinting.__doc__ = init_vprinting.__doc__.format(params)  # type: ignore

rl/Lib/site-packages/sympy/physics/vector/tests/test_dyadic.py

@@ -0,0 +1,123 @@
+from sympy.core.numbers import (Float, pi)
+from sympy.core.symbol import symbols
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix
+from sympy.physics.vector import ReferenceFrame, dynamicsymbols, outer
+from sympy.physics.vector.dyadic import _check_dyadic
+from sympy.testing.pytest import raises
+
+A = ReferenceFrame('A')
+
+
+def test_dyadic():
+    d1 = A.x | A.x
+    d2 = A.y | A.y
+    d3 = A.x | A.y
+    assert d1 * 0 == 0
+    assert d1 != 0
+    assert d1 * 2 == 2 * A.x | A.x
+    assert d1 / 2. == 0.5 * d1
+    assert d1 & (0 * d1) == 0
+    assert d1 & d2 == 0
+    assert d1 & A.x == A.x
+    assert d1 ^ A.x == 0
+    assert d1 ^ A.y == A.x | A.z
+    assert d1 ^ A.z == - A.x | A.y
+    assert d2 ^ A.x == - A.y | A.z
+    assert A.x ^ d1 == 0
+    assert A.y ^ d1 == - A.z | A.x
+    assert A.z ^ d1 == A.y | A.x
+    assert A.x & d1 == A.x
+    assert A.y & d1 == 0
+    assert A.y & d2 == A.y
+    assert d1 & d3 == A.x | A.y
+    assert d3 & d1 == 0
+    assert d1.dt(A) == 0
+    q = dynamicsymbols('q')
+    qd = dynamicsymbols('q', 1)
+    B = A.orientnew('B', 'Axis', [q, A.z])
+    assert d1.express(B) == d1.express(B, B)
+    assert d1.express(B) == ((cos(q)**2) * (B.x | B.x) + (-sin(q) * cos(q)) *
+            (B.x | B.y) + (-sin(q) * cos(q)) * (B.y | B.x) + (sin(q)**2) *
+            (B.y | B.y))
+    assert d1.express(B, A) == (cos(q)) * (B.x | A.x) + (-sin(q)) * (B.y | A.x)
+    assert d1.express(A, B) == (cos(q)) * (A.x | B.x) + (-sin(q)) * (A.x | B.y)
+    assert d1.dt(B) == (-qd) * (A.y | A.x) + (-qd) * (A.x | A.y)
+
+    assert d1.to_matrix(A) == Matrix([[1, 0, 0], [0, 0, 0], [0, 0, 0]])
+    assert d1.to_matrix(A, B) == Matrix([[cos(q), -sin(q), 0],
+                                         [0, 0, 0],
+                                         [0, 0, 0]])
+    assert d3.to_matrix(A) == Matrix([[0, 1, 0], [0, 0, 0], [0, 0, 0]])
+    a, b, c, d, e, f = symbols('a, b, c, d, e, f')
+    v1 = a * A.x + b * A.y + c * A.z
+    v2 = d * A.x + e * A.y + f * A.z
+    d4 = v1.outer(v2)
+    assert d4.to_matrix(A) == Matrix([[a * d, a * e, a * f],
+                                      [b * d, b * e, b * f],
+                                      [c * d, c * e, c * f]])
+    d5 = v1.outer(v1)
+    C = A.orientnew('C', 'Axis', [q, A.x])
+    for expected, actual in zip(C.dcm(A) * d5.to_matrix(A) * C.dcm(A).T,
+                                d5.to_matrix(C)):
+        assert (expected - actual).simplify() == 0
+
+    raises(TypeError, lambda: d1.applyfunc(0))
+
+
+def test_dyadic_simplify():
+    x, y, z, k, n, m, w, f, s, A = symbols('x, y, z, k, n, m, w, f, s, A')
+    N = ReferenceFrame('N')
+
+    dy = N.x | N.x
+    test1 = (1 / x + 1 / y) * dy
+    assert (N.x & test1 & N.x) != (x + y) / (x * y)
+    test1 = test1.simplify()
+    assert (N.x & test1 & N.x) == (x + y) / (x * y)
+
+    test2 = (A**2 * s**4 / (4 * pi * k * m**3)) * dy
+    test2 = test2.simplify()
+    assert (N.x & test2 & N.x) == (A**2 * s**4 / (4 * pi * k * m**3))
+
+    test3 = ((4 + 4 * x - 2 * (2 + 2 * x)) / (2 + 2 * x)) * dy
+    test3 = test3.simplify()
+    assert (N.x & test3 & N.x) == 0
+
+    test4 = ((-4 * x * y**2 - 2 * y**3 - 2 * x**2 * y) / (x + y)**2) * dy
+    test4 = test4.simplify()
+    assert (N.x & test4 & N.x) == -2 * y
+
+
+def test_dyadic_subs():
+    N = ReferenceFrame('N')
+    s = symbols('s')
+    a = s*(N.x | N.x)
+    assert a.subs({s: 2}) == 2*(N.x | N.x)
+
+
+def test_check_dyadic():
+    raises(TypeError, lambda: _check_dyadic(0))
+
+
+def test_dyadic_evalf():
+    N = ReferenceFrame('N')
+    a = pi * (N.x | N.x)
+    assert a.evalf(3) == Float('3.1416', 3) * (N.x | N.x)
+    s = symbols('s')
+    a = 5 * s * pi* (N.x | N.x)
+    assert a.evalf(2) == Float('5', 2) * Float('3.1416', 2) * s * (N.x | N.x)
+    assert a.evalf(9, subs={s: 5.124}) == Float('80.48760378', 9) * (N.x | N.x)
+
+
+def test_dyadic_xreplace():
+    x, y, z = symbols('x y z')
+    N = ReferenceFrame('N')
+    D = outer(N.x, N.x)
+    v = x*y * D
+    assert v.xreplace({x : cos(x)}) == cos(x)*y * D
+    assert v.xreplace({x*y : pi}) == pi * D
+    v = (x*y)**z * D
+    assert v.xreplace({(x*y)**z : 1}) == D
+    assert v.xreplace({x:1, z:0}) == D
+    raises(TypeError, lambda: v.xreplace())
+    raises(TypeError, lambda: v.xreplace([x, y]))

rl/Lib/site-packages/sympy/physics/vector/tests/test_fieldfunctions.py

@@ -0,0 +1,133 @@
+from sympy.core.singleton import S
+from sympy.core.symbol import Symbol
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.physics.vector import ReferenceFrame, Vector, Point, \
+     dynamicsymbols
+from sympy.physics.vector.fieldfunctions import divergence, \
+     gradient, curl, is_conservative, is_solenoidal, \
+     scalar_potential, scalar_potential_difference
+from sympy.testing.pytest import raises
+
+R = ReferenceFrame('R')
+q = dynamicsymbols('q')
+P = R.orientnew('P', 'Axis', [q, R.z])
+
+
+def test_curl():
+    assert curl(Vector(0), R) == Vector(0)
+    assert curl(R.x, R) == Vector(0)
+    assert curl(2*R[1]**2*R.y, R) == Vector(0)
+    assert curl(R[0]*R[1]*R.z, R) == R[0]*R.x - R[1]*R.y
+    assert curl(R[0]*R[1]*R[2] * (R.x+R.y+R.z), R) == \
+           (-R[0]*R[1] + R[0]*R[2])*R.x + (R[0]*R[1] - R[1]*R[2])*R.y + \
+           (-R[0]*R[2] + R[1]*R[2])*R.z
+    assert curl(2*R[0]**2*R.y, R) == 4*R[0]*R.z
+    assert curl(P[0]**2*R.x + P.y, R) == \
+           - 2*(R[0]*cos(q) + R[1]*sin(q))*sin(q)*R.z
+    assert curl(P[0]*R.y, P) == cos(q)*P.z
+
+
+def test_divergence():
+    assert divergence(Vector(0), R) is S.Zero
+    assert divergence(R.x, R) is S.Zero
+    assert divergence(R[0]**2*R.x, R) == 2*R[0]
+    assert divergence(R[0]*R[1]*R[2] * (R.x+R.y+R.z), R) == \
+           R[0]*R[1] + R[0]*R[2] + R[1]*R[2]
+    assert divergence((1/(R[0]*R[1]*R[2])) * (R.x+R.y+R.z), R) == \
+           -1/(R[0]*R[1]*R[2]**2) - 1/(R[0]*R[1]**2*R[2]) - \
+           1/(R[0]**2*R[1]*R[2])
+    v = P[0]*P.x + P[1]*P.y + P[2]*P.z
+    assert divergence(v, P) == 3
+    assert divergence(v, R).simplify() == 3
+    assert divergence(P[0]*R.x + R[0]*P.x, R) == 2*cos(q)
+
+
+def test_gradient():
+    a = Symbol('a')
+    assert gradient(0, R) == Vector(0)
+    assert gradient(R[0], R) == R.x
+    assert gradient(R[0]*R[1]*R[2], R) == \
+           R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z
+    assert gradient(2*R[0]**2, R) == 4*R[0]*R.x
+    assert gradient(a*sin(R[1])/R[0], R) == \
+           - a*sin(R[1])/R[0]**2*R.x + a*cos(R[1])/R[0]*R.y
+    assert gradient(P[0]*P[1], R) == \
+           ((-R[0]*sin(q) + R[1]*cos(q))*cos(q) - (R[0]*cos(q) + R[1]*sin(q))*sin(q))*R.x + \
+           ((-R[0]*sin(q) + R[1]*cos(q))*sin(q) + (R[0]*cos(q) + R[1]*sin(q))*cos(q))*R.y
+    assert gradient(P[0]*R[2], P) == P[2]*P.x + P[0]*P.z
+
+
+scalar_field = 2*R[0]**2*R[1]*R[2]
+grad_field = gradient(scalar_field, R)
+vector_field = R[1]**2*R.x + 3*R[0]*R.y + 5*R[1]*R[2]*R.z
+curl_field = curl(vector_field, R)
+
+
+def test_conservative():
+    assert is_conservative(0) is True
+    assert is_conservative(R.x) is True
+    assert is_conservative(2 * R.x + 3 * R.y + 4 * R.z) is True
+    assert is_conservative(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) is \
+           True
+    assert is_conservative(R[0] * R.y) is False
+    assert is_conservative(grad_field) is True
+    assert is_conservative(curl_field) is False
+    assert is_conservative(4*R[0]*R[1]*R[2]*R.x + 2*R[0]**2*R[2]*R.y) is \
+                           False
+    assert is_conservative(R[2]*P.x + P[0]*R.z) is True
+
+
+def test_solenoidal():
+    assert is_solenoidal(0) is True
+    assert is_solenoidal(R.x) is True
+    assert is_solenoidal(2 * R.x + 3 * R.y + 4 * R.z) is True
+    assert is_solenoidal(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) is \
+           True
+    assert is_solenoidal(R[1] * R.y) is False
+    assert is_solenoidal(grad_field) is False
+    assert is_solenoidal(curl_field) is True
+    assert is_solenoidal((-2*R[1] + 3)*R.z) is True
+    assert is_solenoidal(cos(q)*R.x + sin(q)*R.y + cos(q)*P.z) is True
+    assert is_solenoidal(R[2]*P.x + P[0]*R.z) is True
+
+
+def test_scalar_potential():
+    assert scalar_potential(0, R) == 0
+    assert scalar_potential(R.x, R) == R[0]
+    assert scalar_potential(R.y, R) == R[1]
+    assert scalar_potential(R.z, R) == R[2]
+    assert scalar_potential(R[1]*R[2]*R.x + R[0]*R[2]*R.y + \
+                            R[0]*R[1]*R.z, R) == R[0]*R[1]*R[2]
+    assert scalar_potential(grad_field, R) == scalar_field
+    assert scalar_potential(R[2]*P.x + P[0]*R.z, R) == \
+           R[0]*R[2]*cos(q) + R[1]*R[2]*sin(q)
+    assert scalar_potential(R[2]*P.x + P[0]*R.z, P) == P[0]*P[2]
+    raises(ValueError, lambda: scalar_potential(R[0] * R.y, R))
+
+
+def test_scalar_potential_difference():
+    origin = Point('O')
+    point1 = origin.locatenew('P1', 1*R.x + 2*R.y + 3*R.z)
+    point2 = origin.locatenew('P2', 4*R.x + 5*R.y + 6*R.z)
+    genericpointR = origin.locatenew('RP', R[0]*R.x + R[1]*R.y + R[2]*R.z)
+    genericpointP = origin.locatenew('PP', P[0]*P.x + P[1]*P.y + P[2]*P.z)
+    assert scalar_potential_difference(S.Zero, R, point1, point2, \
+                                       origin) == 0
+    assert scalar_potential_difference(scalar_field, R, origin, \
+                                       genericpointR, origin) == \
+                                       scalar_field
+    assert scalar_potential_difference(grad_field, R, origin, \
+                                       genericpointR, origin) == \
+                                       scalar_field
+    assert scalar_potential_difference(grad_field, R, point1, point2,
+                                       origin) == 948
+    assert scalar_potential_difference(R[1]*R[2]*R.x + R[0]*R[2]*R.y + \
+                                       R[0]*R[1]*R.z, R, point1,
+                                       genericpointR, origin) == \
+                                       R[0]*R[1]*R[2] - 6
+    potential_diff_P = 2*P[2]*(P[0]*sin(q) + P[1]*cos(q))*\
+                       (P[0]*cos(q) - P[1]*sin(q))**2
+    assert scalar_potential_difference(grad_field, P, origin, \
+                                       genericpointP, \
+                                       origin).simplify() == \
+                                       potential_diff_P

rl/Lib/site-packages/sympy/physics/vector/tests/test_frame.py

@@ -0,0 +1,761 @@
+from sympy.core.numbers import pi
+from sympy.core.symbol import symbols
+from sympy.simplify import trigsimp
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.matrices.dense import (eye, zeros)
+from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix
+from sympy.simplify.simplify import simplify
+from sympy.physics.vector import (ReferenceFrame, Vector, CoordinateSym,
+                                  dynamicsymbols, time_derivative, express,
+                                  dot)
+from sympy.physics.vector.frame import _check_frame
+from sympy.physics.vector.vector import VectorTypeError
+from sympy.testing.pytest import raises
+import warnings
+import pickle
+
+
+def test_dict_list():
+
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+    D = ReferenceFrame('D')
+    E = ReferenceFrame('E')
+    F = ReferenceFrame('F')
+
+    B.orient_axis(A, A.x, 1.0)
+    C.orient_axis(B, B.x, 1.0)
+    D.orient_axis(C, C.x, 1.0)
+
+    assert D._dict_list(A, 0) == [D, C, B, A]
+
+    E.orient_axis(D, D.x, 1.0)
+
+    assert C._dict_list(A, 0) == [C, B, A]
+    assert C._dict_list(E, 0) == [C, D, E]
+
+    # only 0, 1, 2 permitted for second argument
+    raises(ValueError, lambda: C._dict_list(E, 5))
+    # no connecting path
+    raises(ValueError, lambda: F._dict_list(A, 0))
+
+
+def test_coordinate_vars():
+    """Tests the coordinate variables functionality"""
+    A = ReferenceFrame('A')
+    assert CoordinateSym('Ax', A, 0) == A[0]
+    assert CoordinateSym('Ax', A, 1) == A[1]
+    assert CoordinateSym('Ax', A, 2) == A[2]
+    raises(ValueError, lambda: CoordinateSym('Ax', A, 3))
+    q = dynamicsymbols('q')
+    qd = dynamicsymbols('q', 1)
+    assert isinstance(A[0], CoordinateSym) and \
+           isinstance(A[0], CoordinateSym) and \
+           isinstance(A[0], CoordinateSym)
+    assert A.variable_map(A) == {A[0]:A[0], A[1]:A[1], A[2]:A[2]}
+    assert A[0].frame == A
+    B = A.orientnew('B', 'Axis', [q, A.z])
+    assert B.variable_map(A) == {B[2]: A[2], B[1]: -A[0]*sin(q) + A[1]*cos(q),
+                                 B[0]: A[0]*cos(q) + A[1]*sin(q)}
+    assert A.variable_map(B) == {A[0]: B[0]*cos(q) - B[1]*sin(q),
+                                 A[1]: B[0]*sin(q) + B[1]*cos(q), A[2]: B[2]}
+    assert time_derivative(B[0], A) == -A[0]*sin(q)*qd + A[1]*cos(q)*qd
+    assert time_derivative(B[1], A) == -A[0]*cos(q)*qd - A[1]*sin(q)*qd
+    assert time_derivative(B[2], A) == 0
+    assert express(B[0], A, variables=True) == A[0]*cos(q) + A[1]*sin(q)
+    assert express(B[1], A, variables=True) == -A[0]*sin(q) + A[1]*cos(q)
+    assert express(B[2], A, variables=True) == A[2]
+    assert time_derivative(A[0]*A.x + A[1]*A.y + A[2]*A.z, B) == A[1]*qd*A.x - A[0]*qd*A.y
+    assert time_derivative(B[0]*B.x + B[1]*B.y + B[2]*B.z, A) == - B[1]*qd*B.x + B[0]*qd*B.y
+    assert express(B[0]*B[1]*B[2], A, variables=True) == \
+           A[2]*(-A[0]*sin(q) + A[1]*cos(q))*(A[0]*cos(q) + A[1]*sin(q))
+    assert (time_derivative(B[0]*B[1]*B[2], A) -
+            (A[2]*(-A[0]**2*cos(2*q) -
+             2*A[0]*A[1]*sin(2*q) +
+             A[1]**2*cos(2*q))*qd)).trigsimp() == 0
+    assert express(B[0]*B.x + B[1]*B.y + B[2]*B.z, A) == \
+           (B[0]*cos(q) - B[1]*sin(q))*A.x + (B[0]*sin(q) + \
+           B[1]*cos(q))*A.y + B[2]*A.z
+    assert express(B[0]*B.x + B[1]*B.y + B[2]*B.z, A,
+                   variables=True).simplify() == A[0]*A.x + A[1]*A.y + A[2]*A.z
+    assert express(A[0]*A.x + A[1]*A.y + A[2]*A.z, B) == \
+           (A[0]*cos(q) + A[1]*sin(q))*B.x + \
+           (-A[0]*sin(q) + A[1]*cos(q))*B.y + A[2]*B.z
+    assert express(A[0]*A.x + A[1]*A.y + A[2]*A.z, B,
+                   variables=True).simplify() == B[0]*B.x + B[1]*B.y + B[2]*B.z
+    N = B.orientnew('N', 'Axis', [-q, B.z])
+    assert ({k: v.simplify() for k, v in N.variable_map(A).items()} ==
+            {N[0]: A[0], N[2]: A[2], N[1]: A[1]})
+    C = A.orientnew('C', 'Axis', [q, A.x + A.y + A.z])
+    mapping = A.variable_map(C)
+    assert trigsimp(mapping[A[0]]) == (2*C[0]*cos(q)/3 + C[0]/3 -
+                                       2*C[1]*sin(q + pi/6)/3 +
+                                       C[1]/3 - 2*C[2]*cos(q + pi/3)/3 +
+                                       C[2]/3)
+    assert trigsimp(mapping[A[1]]) == -2*C[0]*cos(q + pi/3)/3 + \
+           C[0]/3 + 2*C[1]*cos(q)/3 + C[1]/3 - 2*C[2]*sin(q + pi/6)/3 + C[2]/3
+    assert trigsimp(mapping[A[2]]) == -2*C[0]*sin(q + pi/6)/3 + C[0]/3 - \
+           2*C[1]*cos(q + pi/3)/3 + C[1]/3 + 2*C[2]*cos(q)/3 + C[2]/3
+
+
+def test_ang_vel():
+    q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4')
+    q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1)
+    N = ReferenceFrame('N')
+    A = N.orientnew('A', 'Axis', [q1, N.z])
+    B = A.orientnew('B', 'Axis', [q2, A.x])
+    C = B.orientnew('C', 'Axis', [q3, B.y])
+    D = N.orientnew('D', 'Axis', [q4, N.y])
+    u1, u2, u3 = dynamicsymbols('u1 u2 u3')
+    assert A.ang_vel_in(N) == (q1d)*A.z
+    assert B.ang_vel_in(N) == (q2d)*B.x + (q1d)*A.z
+    assert C.ang_vel_in(N) == (q3d)*C.y + (q2d)*B.x + (q1d)*A.z
+
+    A2 = N.orientnew('A2', 'Axis', [q4, N.y])
+    assert N.ang_vel_in(N) == 0
+    assert N.ang_vel_in(A) == -q1d*N.z
+    assert N.ang_vel_in(B) == -q1d*A.z - q2d*B.x
+    assert N.ang_vel_in(C) == -q1d*A.z - q2d*B.x - q3d*B.y
+    assert N.ang_vel_in(A2) == -q4d*N.y
+
+    assert A.ang_vel_in(N) == q1d*N.z
+    assert A.ang_vel_in(A) == 0
+    assert A.ang_vel_in(B) == - q2d*B.x
+    assert A.ang_vel_in(C) == - q2d*B.x - q3d*B.y
+    assert A.ang_vel_in(A2) == q1d*N.z - q4d*N.y
+
+    assert B.ang_vel_in(N) == q1d*A.z + q2d*A.x
+    assert B.ang_vel_in(A) == q2d*A.x
+    assert B.ang_vel_in(B) == 0
+    assert B.ang_vel_in(C) == -q3d*B.y
+    assert B.ang_vel_in(A2) == q1d*A.z + q2d*A.x - q4d*N.y
+
+    assert C.ang_vel_in(N) == q1d*A.z + q2d*A.x + q3d*B.y
+    assert C.ang_vel_in(A) == q2d*A.x + q3d*C.y
+    assert C.ang_vel_in(B) == q3d*B.y
+    assert C.ang_vel_in(C) == 0
+    assert C.ang_vel_in(A2) == q1d*A.z + q2d*A.x + q3d*B.y - q4d*N.y
+
+    assert A2.ang_vel_in(N) == q4d*A2.y
+    assert A2.ang_vel_in(A) == q4d*A2.y - q1d*N.z
+    assert A2.ang_vel_in(B) == q4d*N.y - q1d*A.z - q2d*A.x
+    assert A2.ang_vel_in(C) == q4d*N.y - q1d*A.z - q2d*A.x - q3d*B.y
+    assert A2.ang_vel_in(A2) == 0
+
+    C.set_ang_vel(N, u1*C.x + u2*C.y + u3*C.z)
+    assert C.ang_vel_in(N) == (u1)*C.x + (u2)*C.y + (u3)*C.z
+    assert N.ang_vel_in(C) == (-u1)*C.x + (-u2)*C.y + (-u3)*C.z
+    assert C.ang_vel_in(D) == (u1)*C.x + (u2)*C.y + (u3)*C.z + (-q4d)*D.y
+    assert D.ang_vel_in(C) == (-u1)*C.x + (-u2)*C.y + (-u3)*C.z + (q4d)*D.y
+
+    q0 = dynamicsymbols('q0')
+    q0d = dynamicsymbols('q0', 1)
+    E = N.orientnew('E', 'Quaternion', (q0, q1, q2, q3))
+    assert E.ang_vel_in(N) == (
+        2 * (q1d * q0 + q2d * q3 - q3d * q2 - q0d * q1) * E.x +
+        2 * (q2d * q0 + q3d * q1 - q1d * q3 - q0d * q2) * E.y +
+        2 * (q3d * q0 + q1d * q2 - q2d * q1 - q0d * q3) * E.z)
+
+    F = N.orientnew('F', 'Body', (q1, q2, q3), 313)
+    assert F.ang_vel_in(N) == ((sin(q2)*sin(q3)*q1d + cos(q3)*q2d)*F.x +
+        (sin(q2)*cos(q3)*q1d - sin(q3)*q2d)*F.y + (cos(q2)*q1d + q3d)*F.z)
+    G = N.orientnew('G', 'Axis', (q1, N.x + N.y))
+    assert G.ang_vel_in(N) == q1d * (N.x + N.y).normalize()
+    assert N.ang_vel_in(G) == -q1d * (N.x + N.y).normalize()
+
+
+def test_dcm():
+    q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4')
+    N = ReferenceFrame('N')
+    A = N.orientnew('A', 'Axis', [q1, N.z])
+    B = A.orientnew('B', 'Axis', [q2, A.x])
+    C = B.orientnew('C', 'Axis', [q3, B.y])
+    D = N.orientnew('D', 'Axis', [q4, N.y])
+    E = N.orientnew('E', 'Space', [q1, q2, q3], '123')
+    assert N.dcm(C) == Matrix([
+        [- sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), - sin(q1) *
+        cos(q2), sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)], [sin(q1) *
+        cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), sin(q1) *
+            sin(q3) - sin(q2) * cos(q1) * cos(q3)], [- sin(q3) * cos(q2), sin(q2),
+        cos(q2) * cos(q3)]])
+    # This is a little touchy.  Is it ok to use simplify in assert?
+    test_mat = D.dcm(C) - Matrix(
+        [[cos(q1) * cos(q3) * cos(q4) - sin(q3) * (- sin(q4) * cos(q2) +
+        sin(q1) * sin(q2) * cos(q4)), - sin(q2) * sin(q4) - sin(q1) *
+            cos(q2) * cos(q4), sin(q3) * cos(q1) * cos(q4) + cos(q3) * (- sin(q4) *
+        cos(q2) + sin(q1) * sin(q2) * cos(q4))], [sin(q1) * cos(q3) +
+        sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), sin(q1) * sin(q3) -
+            sin(q2) * cos(q1) * cos(q3)], [sin(q4) * cos(q1) * cos(q3) -
+        sin(q3) * (cos(q2) * cos(q4) + sin(q1) * sin(q2) * sin(q4)), sin(q2) *
+                cos(q4) - sin(q1) * sin(q4) * cos(q2), sin(q3) * sin(q4) * cos(q1) +
+                cos(q3) * (cos(q2) * cos(q4) + sin(q1) * sin(q2) * sin(q4))]])
+    assert test_mat.expand() == zeros(3, 3)
+    assert E.dcm(N) == Matrix(
+        [[cos(q2)*cos(q3), sin(q3)*cos(q2), -sin(q2)],
+        [sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) +
+        cos(q1)*cos(q3), sin(q1)*cos(q2)], [sin(q1)*sin(q3) +
+        sin(q2)*cos(q1)*cos(q3), - sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1),
+         cos(q1)*cos(q2)]])
+
+def test_w_diff_dcm1():
+    # Ref:
+    # Dynamics Theory and Applications, Kane 1985
+    # Sec. 2.1 ANGULAR VELOCITY
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+
+    c11, c12, c13 = dynamicsymbols('C11 C12 C13')
+    c21, c22, c23 = dynamicsymbols('C21 C22 C23')
+    c31, c32, c33 = dynamicsymbols('C31 C32 C33')
+
+    c11d, c12d, c13d = dynamicsymbols('C11 C12 C13', level=1)
+    c21d, c22d, c23d = dynamicsymbols('C21 C22 C23', level=1)
+    c31d, c32d, c33d = dynamicsymbols('C31 C32 C33', level=1)
+
+    DCM = Matrix([
+        [c11, c12, c13],
+        [c21, c22, c23],
+        [c31, c32, c33]
+    ])
+
+    B.orient(A, 'DCM', DCM)
+    b1a = (B.x).express(A)
+    b2a = (B.y).express(A)
+    b3a = (B.z).express(A)
+
+    # Equation (2.1.1)
+    B.set_ang_vel(A, B.x*(dot((b3a).dt(A), B.y))
+                   + B.y*(dot((b1a).dt(A), B.z))
+                   + B.z*(dot((b2a).dt(A), B.x)))
+
+    # Equation (2.1.21)
+    expr = (  (c12*c13d + c22*c23d + c32*c33d)*B.x
+            + (c13*c11d + c23*c21d + c33*c31d)*B.y
+            + (c11*c12d + c21*c22d + c31*c32d)*B.z)
+    assert B.ang_vel_in(A) - expr == 0
+
+def test_w_diff_dcm2():
+    q1, q2, q3 = dynamicsymbols('q1:4')
+    N = ReferenceFrame('N')
+    A = N.orientnew('A', 'axis', [q1, N.x])
+    B = A.orientnew('B', 'axis', [q2, A.y])
+    C = B.orientnew('C', 'axis', [q3, B.z])
+
+    DCM = C.dcm(N).T
+    D = N.orientnew('D', 'DCM', DCM)
+
+    # Frames D and C are the same ReferenceFrame,
+    # since they have equal DCM respect to frame N.
+    # Therefore, D and C should have same angle velocity in N.
+    assert D.dcm(N) == C.dcm(N) == Matrix([
+        [cos(q2)*cos(q3), sin(q1)*sin(q2)*cos(q3) +
+        sin(q3)*cos(q1), sin(q1)*sin(q3) -
+        sin(q2)*cos(q1)*cos(q3)], [-sin(q3)*cos(q2),
+        -sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3),
+        sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)],
+        [sin(q2), -sin(q1)*cos(q2), cos(q1)*cos(q2)]])
+    assert (D.ang_vel_in(N) - C.ang_vel_in(N)).express(N).simplify() == 0
+
+def test_orientnew_respects_parent_class():
+    class MyReferenceFrame(ReferenceFrame):
+        pass
+    B = MyReferenceFrame('B')
+    C = B.orientnew('C', 'Axis', [0, B.x])
+    assert isinstance(C, MyReferenceFrame)
+
+
+def test_orientnew_respects_input_indices():
+    N = ReferenceFrame('N')
+    q1 = dynamicsymbols('q1')
+    A = N.orientnew('a', 'Axis', [q1, N.z])
+    #modify default indices:
+    minds = [x+'1' for x in N.indices]
+    B = N.orientnew('b', 'Axis', [q1, N.z], indices=minds)
+
+    assert N.indices == A.indices
+    assert B.indices == minds
+
+def test_orientnew_respects_input_latexs():
+    N = ReferenceFrame('N')
+    q1 = dynamicsymbols('q1')
+    A = N.orientnew('a', 'Axis', [q1, N.z])
+
+    #build default and alternate latex_vecs:
+    def_latex_vecs = [(r"\mathbf{\hat{%s}_%s}" % (A.name.lower(),
+                      A.indices[0])), (r"\mathbf{\hat{%s}_%s}" %
+                      (A.name.lower(), A.indices[1])),
+                      (r"\mathbf{\hat{%s}_%s}" % (A.name.lower(),
+                      A.indices[2]))]
+
+    name = 'b'
+    indices = [x+'1' for x in N.indices]
+    new_latex_vecs = [(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(),
+                      indices[0])), (r"\mathbf{\hat{%s}_{%s}}" %
+                      (name.lower(), indices[1])),
+                      (r"\mathbf{\hat{%s}_{%s}}" % (name.lower(),
+                      indices[2]))]
+
+    B = N.orientnew(name, 'Axis', [q1, N.z], latexs=new_latex_vecs)
+
+    assert A.latex_vecs == def_latex_vecs
+    assert B.latex_vecs == new_latex_vecs
+    assert B.indices != indices
+
+def test_orientnew_respects_input_variables():
+    N = ReferenceFrame('N')
+    q1 = dynamicsymbols('q1')
+    A = N.orientnew('a', 'Axis', [q1, N.z])
+
+    #build non-standard variable names
+    name = 'b'
+    new_variables = ['notb_'+x+'1' for x in N.indices]
+    B = N.orientnew(name, 'Axis', [q1, N.z], variables=new_variables)
+
+    for j,var in enumerate(A.varlist):
+        assert var.name == A.name + '_' + A.indices[j]
+
+    for j,var in enumerate(B.varlist):
+        assert var.name == new_variables[j]
+
+def test_issue_10348():
+    u = dynamicsymbols('u:3')
+    I = ReferenceFrame('I')
+    I.orientnew('A', 'space', u, 'XYZ')
+
+
+def test_issue_11503():
+    A = ReferenceFrame("A")
+    A.orientnew("B", "Axis", [35, A.y])
+    C = ReferenceFrame("C")
+    A.orient(C, "Axis", [70, C.z])
+
+
+def test_partial_velocity():
+
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+
+    u1, u2 = dynamicsymbols('u1, u2')
+
+    A.set_ang_vel(N, u1 * A.x + u2 * N.y)
+
+    assert N.partial_velocity(A, u1) == -A.x
+    assert N.partial_velocity(A, u1, u2) == (-A.x, -N.y)
+
+    assert A.partial_velocity(N, u1) == A.x
+    assert A.partial_velocity(N, u1, u2) == (A.x, N.y)
+
+    assert N.partial_velocity(N, u1) == 0
+    assert A.partial_velocity(A, u1) == 0
+
+
+def test_issue_11498():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+
+    # Identity transformation
+    A.orient(B, 'DCM', eye(3))
+    assert A.dcm(B) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
+    assert B.dcm(A) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
+
+    # x -> y
+    # y -> -z
+    # z -> -x
+    A.orient(B, 'DCM', Matrix([[0, 1, 0], [0, 0, -1], [-1, 0, 0]]))
+    assert B.dcm(A) == Matrix([[0, 1, 0], [0, 0, -1], [-1, 0, 0]])
+    assert A.dcm(B) == Matrix([[0, 0, -1], [1, 0, 0], [0, -1, 0]])
+    assert B.dcm(A).T == A.dcm(B)
+
+
+def test_reference_frame():
+    raises(TypeError, lambda: ReferenceFrame(0))
+    raises(TypeError, lambda: ReferenceFrame('N', 0))
+    raises(ValueError, lambda: ReferenceFrame('N', [0, 1]))
+    raises(TypeError, lambda: ReferenceFrame('N', [0, 1, 2]))
+    raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], 0))
+    raises(ValueError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], [0, 1]))
+    raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], [0, 1, 2]))
+    raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'],
+                                                 ['a', 'b', 'c'], 0))
+    raises(ValueError, lambda: ReferenceFrame('N', ['a', 'b', 'c'],
+                                              ['a', 'b', 'c'], [0, 1]))
+    raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'],
+                                             ['a', 'b', 'c'], [0, 1, 2]))
+    N = ReferenceFrame('N')
+    assert N[0] == CoordinateSym('N_x', N, 0)
+    assert N[1] == CoordinateSym('N_y', N, 1)
+    assert N[2] == CoordinateSym('N_z', N, 2)
+    raises(ValueError, lambda: N[3])
+    N = ReferenceFrame('N', ['a', 'b', 'c'])
+    assert N['a'] == N.x
+    assert N['b'] == N.y
+    assert N['c'] == N.z
+    raises(ValueError, lambda: N['d'])
+    assert str(N) == 'N'
+
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    q0, q1, q2, q3 = symbols('q0 q1 q2 q3')
+    raises(TypeError, lambda: A.orient(B, 'DCM', 0))
+    raises(TypeError, lambda: B.orient(N, 'Space', [q1, q2, q3], '222'))
+    raises(TypeError, lambda: B.orient(N, 'Axis', [q1, N.x + 2 * N.y], '222'))
+    raises(TypeError, lambda: B.orient(N, 'Axis', q1))
+    raises(IndexError, lambda: B.orient(N, 'Axis', [q1]))
+    raises(TypeError, lambda: B.orient(N, 'Quaternion', [q0, q1, q2, q3], '222'))
+    raises(TypeError, lambda: B.orient(N, 'Quaternion', q0))
+    raises(TypeError, lambda: B.orient(N, 'Quaternion', [q0, q1, q2]))
+    raises(NotImplementedError, lambda: B.orient(N, 'Foo', [q0, q1, q2]))
+    raises(TypeError, lambda: B.orient(N, 'Body', [q1, q2], '232'))
+    raises(TypeError, lambda: B.orient(N, 'Space', [q1, q2], '232'))
+
+    N.set_ang_acc(B, 0)
+    assert N.ang_acc_in(B) == Vector(0)
+    N.set_ang_vel(B, 0)
+    assert N.ang_vel_in(B) == Vector(0)
+
+
+def test_check_frame():
+    raises(VectorTypeError, lambda: _check_frame(0))
+
+
+def test_dcm_diff_16824():
+    # NOTE : This is a regression test for the bug introduced in PR 14758,
+    # identified in 16824, and solved by PR 16828.
+
+    # This is the solution to Problem 2.2 on page 264 in Kane & Lenvinson's
+    # 1985 book.
+
+    q1, q2, q3 = dynamicsymbols('q1:4')
+
+    s1 = sin(q1)
+    c1 = cos(q1)
+    s2 = sin(q2)
+    c2 = cos(q2)
+    s3 = sin(q3)
+    c3 = cos(q3)
+
+    dcm = Matrix([[c2*c3, s1*s2*c3 - s3*c1, c1*s2*c3 + s3*s1],
+                  [c2*s3, s1*s2*s3 + c3*c1, c1*s2*s3 - c3*s1],
+                  [-s2,   s1*c2,            c1*c2]])
+
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient(A, 'DCM', dcm)
+
+    AwB = B.ang_vel_in(A)
+
+    alpha2 = s3*c2*q1.diff() + c3*q2.diff()
+    beta2 = s1*c2*q3.diff() + c1*q2.diff()
+
+    assert simplify(AwB.dot(A.y) - alpha2) == 0
+    assert simplify(AwB.dot(B.y) - beta2) == 0
+
+def test_orient_explicit():
+    cxx, cyy, czz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}')
+    cxy, cxz, cyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}')
+    cyz, czx, czy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}')
+    dcxx, dcyy, dczz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}', 1)
+    dcxy, dcxz, dcyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}', 1)
+    dcyz, dczx, dczy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}', 1)
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B_C_A = Matrix([[cxx, cxy, cxz],
+                    [cyx, cyy, cyz],
+                    [czx, czy, czz]])
+    B_w_A = ((cyx*dczx + cyy*dczy + cyz*dczz)*B.x +
+            (czx*dcxx + czy*dcxy + czz*dcxz)*B.y +
+            (cxx*dcyx + cxy*dcyy + cxz*dcyz)*B.z)
+    A.orient_explicit(B, B_C_A)
+    assert B.dcm(A) == B_C_A
+    assert A.ang_vel_in(B) == B_w_A
+    assert B.ang_vel_in(A) == -B_w_A
+
+def test_orient_dcm():
+    cxx, cyy, czz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}')
+    cxy, cxz, cyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}')
+    cyz, czx, czy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}')
+    B_C_A = Matrix([[cxx, cxy, cxz],
+                    [cyx, cyy, cyz],
+                    [czx, czy, czz]])
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient_dcm(A, B_C_A)
+    assert B.dcm(A) == Matrix([[cxx, cxy, cxz],
+                               [cyx, cyy, cyz],
+                               [czx, czy, czz]])
+
+def test_orient_axis():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    A.orient_axis(B,-B.x, 1)
+    A1 = A.dcm(B)
+    A.orient_axis(B, B.x, -1)
+    A2 = A.dcm(B)
+    A.orient_axis(B, 1, -B.x)
+    A3 = A.dcm(B)
+    assert A1 == A2
+    assert A2 == A3
+    raises(TypeError, lambda: A.orient_axis(B, 1, 1))
+
+def test_orient_body():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient_body_fixed(A, (1,1,0), 'XYX')
+    assert B.dcm(A) == Matrix([[cos(1), sin(1)**2, -sin(1)*cos(1)], [0, cos(1), sin(1)], [sin(1), -sin(1)*cos(1), cos(1)**2]])
+
+
+def test_orient_body_advanced():
+    q1, q2, q3 = dynamicsymbols('q1:4')
+    c1, c2, c3 = symbols('c1:4')
+    u1, u2, u3 = dynamicsymbols('q1:4', 1)
+
+    # Test with everything as dynamicsymbols
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_body_fixed(A, (q1, q2, q3), 'zxy')
+    assert A.dcm(B) == Matrix([
+        [-sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), -sin(q1) * cos(q2),
+         sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)],
+        [sin(q1) * cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2),
+         sin(q1) * sin(q3) - sin(q2) * cos(q1) * cos(q3)],
+        [-sin(q3) * cos(q2), sin(q2), cos(q2) * cos(q3)]])
+    assert B.ang_vel_in(A).to_matrix(B) == Matrix([
+        [-sin(q3) * cos(q2) * u1 + cos(q3) * u2],
+        [sin(q2) * u1 + u3],
+        [sin(q3) * u2 + cos(q2) * cos(q3) * u1]])
+
+    # Test with constant symbol
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_body_fixed(A, (q1, c2, q3), 131)
+    assert A.dcm(B) == Matrix([
+        [cos(c2), -sin(c2) * cos(q3), sin(c2) * sin(q3)],
+        [sin(c2) * cos(q1), -sin(q1) * sin(q3) + cos(c2) * cos(q1) * cos(q3),
+         -sin(q1) * cos(q3) - sin(q3) * cos(c2) * cos(q1)],
+        [sin(c2) * sin(q1), sin(q1) * cos(c2) * cos(q3) + sin(q3) * cos(q1),
+         -sin(q1) * sin(q3) * cos(c2) + cos(q1) * cos(q3)]])
+    assert B.ang_vel_in(A).to_matrix(B) == Matrix([
+        [cos(c2) * u1 + u3],
+        [-sin(c2) * cos(q3) * u1],
+        [sin(c2) * sin(q3) * u1]])
+
+    # Test all symbols not time dependent
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_body_fixed(A, (c1, c2, c3), 123)
+    assert B.ang_vel_in(A) == Vector(0)
+
+
+def test_orient_space_advanced():
+    # space fixed is in the end like body fixed only in opposite order
+    q1, q2, q3 = dynamicsymbols('q1:4')
+    c1, c2, c3 = symbols('c1:4')
+    u1, u2, u3 = dynamicsymbols('q1:4', 1)
+
+    # Test with everything as dynamicsymbols
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_space_fixed(A, (q3, q2, q1), 'yxz')
+    assert A.dcm(B) == Matrix([
+        [-sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), -sin(q1) * cos(q2),
+         sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)],
+        [sin(q1) * cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2),
+         sin(q1) * sin(q3) - sin(q2) * cos(q1) * cos(q3)],
+        [-sin(q3) * cos(q2), sin(q2), cos(q2) * cos(q3)]])
+    assert B.ang_vel_in(A).to_matrix(B) == Matrix([
+        [-sin(q3) * cos(q2) * u1 + cos(q3) * u2],
+        [sin(q2) * u1 + u3],
+        [sin(q3) * u2 + cos(q2) * cos(q3) * u1]])
+
+    # Test with constant symbol
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_space_fixed(A, (q3, c2, q1), 131)
+    assert A.dcm(B) == Matrix([
+        [cos(c2), -sin(c2) * cos(q3), sin(c2) * sin(q3)],
+        [sin(c2) * cos(q1), -sin(q1) * sin(q3) + cos(c2) * cos(q1) * cos(q3),
+         -sin(q1) * cos(q3) - sin(q3) * cos(c2) * cos(q1)],
+        [sin(c2) * sin(q1), sin(q1) * cos(c2) * cos(q3) + sin(q3) * cos(q1),
+         -sin(q1) * sin(q3) * cos(c2) + cos(q1) * cos(q3)]])
+    assert B.ang_vel_in(A).to_matrix(B) == Matrix([
+        [cos(c2) * u1 + u3],
+        [-sin(c2) * cos(q3) * u1],
+        [sin(c2) * sin(q3) * u1]])
+
+    # Test all symbols not time dependent
+    A, B = ReferenceFrame('A'), ReferenceFrame('B')
+    B.orient_space_fixed(A, (c1, c2, c3), 123)
+    assert B.ang_vel_in(A) == Vector(0)
+
+
+def test_orient_body_simple_ang_vel():
+    """This test ensures that the simplest form of that linear system solution
+    is returned, thus the == for the expression comparison."""
+
+    psi, theta, phi = dynamicsymbols('psi, theta, varphi')
+    t = dynamicsymbols._t
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient_body_fixed(A, (psi, theta, phi), 'ZXZ')
+    A_w_B = B.ang_vel_in(A)
+    assert A_w_B.args[0][1] == B
+    assert A_w_B.args[0][0][0] == (sin(theta)*sin(phi)*psi.diff(t) +
+                                   cos(phi)*theta.diff(t))
+    assert A_w_B.args[0][0][1] == (sin(theta)*cos(phi)*psi.diff(t) -
+                                   sin(phi)*theta.diff(t))
+    assert A_w_B.args[0][0][2] == cos(theta)*psi.diff(t) + phi.diff(t)
+
+
+def test_orient_space():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient_space_fixed(A, (0,0,0), '123')
+    assert B.dcm(A) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
+
+def test_orient_quaternion():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    B.orient_quaternion(A, (0,0,0,0))
+    assert B.dcm(A) == Matrix([[0, 0, 0], [0, 0, 0], [0, 0, 0]])
+
+def test_looped_frame_warning():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+
+    a, b, c = symbols('a b c')
+    B.orient_axis(A, A.x, a)
+    C.orient_axis(B, B.x, b)
+
+    with warnings.catch_warnings(record = True) as w:
+        warnings.simplefilter("always")
+        A.orient_axis(C, C.x, c)
+        assert issubclass(w[-1].category, UserWarning)
+        assert 'Loops are defined among the orientation of frames. ' + \
+            'This is likely not desired and may cause errors in your calculations.' in str(w[-1].message)
+
+def test_frame_dict():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+
+    a, b, c = symbols('a b c')
+
+    B.orient_axis(A, A.x, a)
+    assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a),  cos(a)]])}
+    assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0,  cos(a), sin(a)],[0, -sin(a), cos(a)]])}
+    assert C._dcm_dict == {}
+
+    B.orient_axis(C, C.x, b)
+    # Previous relation is not wiped
+    assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a),  cos(a)]])}
+    assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0,  cos(a), sin(a)],[0, -sin(a), cos(a)]]), \
+        C: Matrix([[1, 0, 0],[0,  cos(b), sin(b)],[0, -sin(b), cos(b)]])}
+    assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b),  cos(b)]])}
+
+    A.orient_axis(B, B.x, c)
+    # Previous relation is updated
+    assert B._dcm_dict == {C: Matrix([[1, 0, 0],[0,  cos(b), sin(b)],[0, -sin(b), cos(b)]]),\
+        A: Matrix([[1, 0, 0],[0, cos(c), -sin(c)],[0, sin(c),  cos(c)]])}
+    assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0,  cos(c), sin(c)],[0, -sin(c), cos(c)]])}
+    assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b),  cos(b)]])}
+
+def test_dcm_cache_dict():
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+    D = ReferenceFrame('D')
+
+    a, b, c = symbols('a b c')
+
+    B.orient_axis(A, A.x, a)
+    C.orient_axis(B, B.x, b)
+    D.orient_axis(C, C.x, c)
+
+    assert D._dcm_dict == {C: Matrix([[1, 0, 0],[0,  cos(c), sin(c)],[0, -sin(c), cos(c)]])}
+    assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0,  cos(b), sin(b)],[0, -sin(b), cos(b)]]), \
+        D: Matrix([[1, 0, 0],[0, cos(c), -sin(c)],[0, sin(c),  cos(c)]])}
+    assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0,  cos(a), sin(a)],[0, -sin(a), cos(a)]]), \
+        C: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b),  cos(b)]])}
+    assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a),  cos(a)]])}
+
+    assert D._dcm_dict == D._dcm_cache
+
+    D.dcm(A) # Check calculated dcm relation is stored in _dcm_cache and not in _dcm_dict
+    assert list(A._dcm_cache.keys()) == [A, B, D]
+    assert list(D._dcm_cache.keys()) == [C, A]
+    assert list(A._dcm_dict.keys()) == [B]
+    assert list(D._dcm_dict.keys()) == [C]
+    assert A._dcm_dict != A._dcm_cache
+
+    A.orient_axis(B, B.x, b) # _dcm_cache of A is wiped out and new relation is stored.
+    assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0,  cos(b), sin(b)],[0, -sin(b), cos(b)]])}
+    assert A._dcm_dict == A._dcm_cache
+    assert B._dcm_dict == {C: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b),  cos(b)]]), \
+        A: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b),  cos(b)]])}
+
+def test_xx_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.xx == Vector.outer(N.x, N.x)
+    assert F.xx == Vector.outer(F.x, F.x)
+
+def test_xy_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.xy == Vector.outer(N.x, N.y)
+    assert F.xy == Vector.outer(F.x, F.y)
+
+def test_xz_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.xz == Vector.outer(N.x, N.z)
+    assert F.xz == Vector.outer(F.x, F.z)
+
+def test_yx_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.yx == Vector.outer(N.y, N.x)
+    assert F.yx == Vector.outer(F.y, F.x)
+
+def test_yy_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.yy == Vector.outer(N.y, N.y)
+    assert F.yy == Vector.outer(F.y, F.y)
+
+def test_yz_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.yz == Vector.outer(N.y, N.z)
+    assert F.yz == Vector.outer(F.y, F.z)
+
+def test_zx_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.zx == Vector.outer(N.z, N.x)
+    assert F.zx == Vector.outer(F.z, F.x)
+
+def test_zy_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.zy == Vector.outer(N.z, N.y)
+    assert F.zy == Vector.outer(F.z, F.y)
+
+def test_zz_dyad():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.zz == Vector.outer(N.z, N.z)
+    assert F.zz == Vector.outer(F.z, F.z)
+
+def test_unit_dyadic():
+    N = ReferenceFrame('N')
+    F = ReferenceFrame('F', indices=['1', '2', '3'])
+    assert N.u == N.xx + N.yy + N.zz
+    assert F.u == F.xx + F.yy + F.zz
+
+
+def test_pickle_frame():
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+    A.orient_axis(N, N.x, 1)
+    A_C_N = A.dcm(N)
+    N1 = pickle.loads(pickle.dumps(N))
+    A1 = tuple(N1._dcm_dict.keys())[0]
+    assert A1.dcm(N1) == A_C_N

rl/Lib/site-packages/sympy/physics/vector/tests/test_functions.py

@@ -0,0 +1,509 @@
+from sympy.core.numbers import pi
+from sympy.core.singleton import S
+from sympy.core.symbol import symbols
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.integrals.integrals import Integral
+from sympy.physics.vector import Dyadic, Point, ReferenceFrame, Vector
+from sympy.physics.vector.functions import (cross, dot, express,
+                                            time_derivative,
+                                            kinematic_equations, outer,
+                                            partial_velocity,
+                                            get_motion_params, dynamicsymbols)
+from sympy.simplify import trigsimp
+from sympy.testing.pytest import raises
+
+q1, q2, q3, q4, q5 = symbols('q1 q2 q3 q4 q5')
+N = ReferenceFrame('N')
+A = N.orientnew('A', 'Axis', [q1, N.z])
+B = A.orientnew('B', 'Axis', [q2, A.x])
+C = B.orientnew('C', 'Axis', [q3, B.y])
+
+
+def test_dot():
+    assert dot(A.x, A.x) == 1
+    assert dot(A.x, A.y) == 0
+    assert dot(A.x, A.z) == 0
+
+    assert dot(A.y, A.x) == 0
+    assert dot(A.y, A.y) == 1
+    assert dot(A.y, A.z) == 0
+
+    assert dot(A.z, A.x) == 0
+    assert dot(A.z, A.y) == 0
+    assert dot(A.z, A.z) == 1
+
+
+def test_dot_different_frames():
+    assert dot(N.x, A.x) == cos(q1)
+    assert dot(N.x, A.y) == -sin(q1)
+    assert dot(N.x, A.z) == 0
+    assert dot(N.y, A.x) == sin(q1)
+    assert dot(N.y, A.y) == cos(q1)
+    assert dot(N.y, A.z) == 0
+    assert dot(N.z, A.x) == 0
+    assert dot(N.z, A.y) == 0
+    assert dot(N.z, A.z) == 1
+
+    assert trigsimp(dot(N.x, A.x + A.y)) == sqrt(2)*cos(q1 + pi/4)
+    assert trigsimp(dot(N.x, A.x + A.y)) == trigsimp(dot(A.x + A.y, N.x))
+
+    assert dot(A.x, C.x) == cos(q3)
+    assert dot(A.x, C.y) == 0
+    assert dot(A.x, C.z) == sin(q3)
+    assert dot(A.y, C.x) == sin(q2)*sin(q3)
+    assert dot(A.y, C.y) == cos(q2)
+    assert dot(A.y, C.z) == -sin(q2)*cos(q3)
+    assert dot(A.z, C.x) == -cos(q2)*sin(q3)
+    assert dot(A.z, C.y) == sin(q2)
+    assert dot(A.z, C.z) == cos(q2)*cos(q3)
+
+
+def test_cross():
+    assert cross(A.x, A.x) == 0
+    assert cross(A.x, A.y) == A.z
+    assert cross(A.x, A.z) == -A.y
+
+    assert cross(A.y, A.x) == -A.z
+    assert cross(A.y, A.y) == 0
+    assert cross(A.y, A.z) == A.x
+
+    assert cross(A.z, A.x) == A.y
+    assert cross(A.z, A.y) == -A.x
+    assert cross(A.z, A.z) == 0
+
+
+def test_cross_different_frames():
+    assert cross(N.x, A.x) == sin(q1)*A.z
+    assert cross(N.x, A.y) == cos(q1)*A.z
+    assert cross(N.x, A.z) == -sin(q1)*A.x - cos(q1)*A.y
+    assert cross(N.y, A.x) == -cos(q1)*A.z
+    assert cross(N.y, A.y) == sin(q1)*A.z
+    assert cross(N.y, A.z) == cos(q1)*A.x - sin(q1)*A.y
+    assert cross(N.z, A.x) == A.y
+    assert cross(N.z, A.y) == -A.x
+    assert cross(N.z, A.z) == 0
+
+    assert cross(N.x, A.x) == sin(q1)*A.z
+    assert cross(N.x, A.y) == cos(q1)*A.z
+    assert cross(N.x, A.x + A.y) == sin(q1)*A.z + cos(q1)*A.z
+    assert cross(A.x + A.y, N.x) == -sin(q1)*A.z - cos(q1)*A.z
+
+    assert cross(A.x, C.x) == sin(q3)*C.y
+    assert cross(A.x, C.y) == -sin(q3)*C.x + cos(q3)*C.z
+    assert cross(A.x, C.z) == -cos(q3)*C.y
+    assert cross(C.x, A.x) == -sin(q3)*C.y
+    assert cross(C.y, A.x).express(C).simplify() == sin(q3)*C.x - cos(q3)*C.z
+    assert cross(C.z, A.x) == cos(q3)*C.y
+
+def test_operator_match():
+    """Test that the output of dot, cross, outer functions match
+    operator behavior.
+    """
+    A = ReferenceFrame('A')
+    v = A.x + A.y
+    d = v | v
+    zerov = Vector(0)
+    zerod = Dyadic(0)
+
+    # dot products
+    assert d & d == dot(d, d)
+    assert d & zerod == dot(d, zerod)
+    assert zerod & d == dot(zerod, d)
+    assert d & v == dot(d, v)
+    assert v & d == dot(v, d)
+    assert d & zerov == dot(d, zerov)
+    assert zerov & d == dot(zerov, d)
+    raises(TypeError, lambda: dot(d, S.Zero))
+    raises(TypeError, lambda: dot(S.Zero, d))
+    raises(TypeError, lambda: dot(d, 0))
+    raises(TypeError, lambda: dot(0, d))
+    assert v & v == dot(v, v)
+    assert v & zerov == dot(v, zerov)
+    assert zerov & v == dot(zerov, v)
+    raises(TypeError, lambda: dot(v, S.Zero))
+    raises(TypeError, lambda: dot(S.Zero, v))
+    raises(TypeError, lambda: dot(v, 0))
+    raises(TypeError, lambda: dot(0, v))
+
+    # cross products
+    raises(TypeError, lambda: cross(d, d))
+    raises(TypeError, lambda: cross(d, zerod))
+    raises(TypeError, lambda: cross(zerod, d))
+    assert d ^ v == cross(d, v)
+    assert v ^ d == cross(v, d)
+    assert d ^ zerov == cross(d, zerov)
+    assert zerov ^ d == cross(zerov, d)
+    assert zerov ^ d == cross(zerov, d)
+    raises(TypeError, lambda: cross(d, S.Zero))
+    raises(TypeError, lambda: cross(S.Zero, d))
+    raises(TypeError, lambda: cross(d, 0))
+    raises(TypeError, lambda: cross(0, d))
+    assert v ^ v == cross(v, v)
+    assert v ^ zerov == cross(v, zerov)
+    assert zerov ^ v == cross(zerov, v)
+    raises(TypeError, lambda: cross(v, S.Zero))
+    raises(TypeError, lambda: cross(S.Zero, v))
+    raises(TypeError, lambda: cross(v, 0))
+    raises(TypeError, lambda: cross(0, v))
+
+    # outer products
+    raises(TypeError, lambda: outer(d, d))
+    raises(TypeError, lambda: outer(d, zerod))
+    raises(TypeError, lambda: outer(zerod, d))
+    raises(TypeError, lambda: outer(d, v))
+    raises(TypeError, lambda: outer(v, d))
+    raises(TypeError, lambda: outer(d, zerov))
+    raises(TypeError, lambda: outer(zerov, d))
+    raises(TypeError, lambda: outer(zerov, d))
+    raises(TypeError, lambda: outer(d, S.Zero))
+    raises(TypeError, lambda: outer(S.Zero, d))
+    raises(TypeError, lambda: outer(d, 0))
+    raises(TypeError, lambda: outer(0, d))
+    assert v | v == outer(v, v)
+    assert v | zerov == outer(v, zerov)
+    assert zerov | v == outer(zerov, v)
+    raises(TypeError, lambda: outer(v, S.Zero))
+    raises(TypeError, lambda: outer(S.Zero, v))
+    raises(TypeError, lambda: outer(v, 0))
+    raises(TypeError, lambda: outer(0, v))
+
+
+def test_express():
+    assert express(Vector(0), N) == Vector(0)
+    assert express(S.Zero, N) is S.Zero
+    assert express(A.x, C) == cos(q3)*C.x + sin(q3)*C.z
+    assert express(A.y, C) == sin(q2)*sin(q3)*C.x + cos(q2)*C.y - \
+        sin(q2)*cos(q3)*C.z
+    assert express(A.z, C) == -sin(q3)*cos(q2)*C.x + sin(q2)*C.y + \
+        cos(q2)*cos(q3)*C.z
+    assert express(A.x, N) == cos(q1)*N.x + sin(q1)*N.y
+    assert express(A.y, N) == -sin(q1)*N.x + cos(q1)*N.y
+    assert express(A.z, N) == N.z
+    assert express(A.x, A) == A.x
+    assert express(A.y, A) == A.y
+    assert express(A.z, A) == A.z
+    assert express(A.x, B) == B.x
+    assert express(A.y, B) == cos(q2)*B.y - sin(q2)*B.z
+    assert express(A.z, B) == sin(q2)*B.y + cos(q2)*B.z
+    assert express(A.x, C) == cos(q3)*C.x + sin(q3)*C.z
+    assert express(A.y, C) == sin(q2)*sin(q3)*C.x + cos(q2)*C.y - \
+        sin(q2)*cos(q3)*C.z
+    assert express(A.z, C) == -sin(q3)*cos(q2)*C.x + sin(q2)*C.y + \
+        cos(q2)*cos(q3)*C.z
+    # Check to make sure UnitVectors get converted properly
+    assert express(N.x, N) == N.x
+    assert express(N.y, N) == N.y
+    assert express(N.z, N) == N.z
+    assert express(N.x, A) == (cos(q1)*A.x - sin(q1)*A.y)
+    assert express(N.y, A) == (sin(q1)*A.x + cos(q1)*A.y)
+    assert express(N.z, A) == A.z
+    assert express(N.x, B) == (cos(q1)*B.x - sin(q1)*cos(q2)*B.y +
+            sin(q1)*sin(q2)*B.z)
+    assert express(N.y, B) == (sin(q1)*B.x + cos(q1)*cos(q2)*B.y -
+            sin(q2)*cos(q1)*B.z)
+    assert express(N.z, B) == (sin(q2)*B.y + cos(q2)*B.z)
+    assert express(N.x, C) == (
+        (cos(q1)*cos(q3) - sin(q1)*sin(q2)*sin(q3))*C.x -
+        sin(q1)*cos(q2)*C.y +
+        (sin(q3)*cos(q1) + sin(q1)*sin(q2)*cos(q3))*C.z)
+    assert express(N.y, C) == (
+        (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*C.x +
+        cos(q1)*cos(q2)*C.y +
+        (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*C.z)
+    assert express(N.z, C) == (-sin(q3)*cos(q2)*C.x + sin(q2)*C.y +
+            cos(q2)*cos(q3)*C.z)
+
+    assert express(A.x, N) == (cos(q1)*N.x + sin(q1)*N.y)
+    assert express(A.y, N) == (-sin(q1)*N.x + cos(q1)*N.y)
+    assert express(A.z, N) == N.z
+    assert express(A.x, A) == A.x
+    assert express(A.y, A) == A.y
+    assert express(A.z, A) == A.z
+    assert express(A.x, B) == B.x
+    assert express(A.y, B) == (cos(q2)*B.y - sin(q2)*B.z)
+    assert express(A.z, B) == (sin(q2)*B.y + cos(q2)*B.z)
+    assert express(A.x, C) == (cos(q3)*C.x + sin(q3)*C.z)
+    assert express(A.y, C) == (sin(q2)*sin(q3)*C.x + cos(q2)*C.y -
+            sin(q2)*cos(q3)*C.z)
+    assert express(A.z, C) == (-sin(q3)*cos(q2)*C.x + sin(q2)*C.y +
+            cos(q2)*cos(q3)*C.z)
+
+    assert express(B.x, N) == (cos(q1)*N.x + sin(q1)*N.y)
+    assert express(B.y, N) == (-sin(q1)*cos(q2)*N.x +
+            cos(q1)*cos(q2)*N.y + sin(q2)*N.z)
+    assert express(B.z, N) == (sin(q1)*sin(q2)*N.x -
+            sin(q2)*cos(q1)*N.y + cos(q2)*N.z)
+    assert express(B.x, A) == A.x
+    assert express(B.y, A) == (cos(q2)*A.y + sin(q2)*A.z)
+    assert express(B.z, A) == (-sin(q2)*A.y + cos(q2)*A.z)
+    assert express(B.x, B) == B.x
+    assert express(B.y, B) == B.y
+    assert express(B.z, B) == B.z
+    assert express(B.x, C) == (cos(q3)*C.x + sin(q3)*C.z)
+    assert express(B.y, C) == C.y
+    assert express(B.z, C) == (-sin(q3)*C.x + cos(q3)*C.z)
+
+    assert express(C.x, N) == (
+        (cos(q1)*cos(q3) - sin(q1)*sin(q2)*sin(q3))*N.x +
+        (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*N.y -
+        sin(q3)*cos(q2)*N.z)
+    assert express(C.y, N) == (
+        -sin(q1)*cos(q2)*N.x + cos(q1)*cos(q2)*N.y + sin(q2)*N.z)
+    assert express(C.z, N) == (
+        (sin(q3)*cos(q1) + sin(q1)*sin(q2)*cos(q3))*N.x +
+        (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*N.y +
+        cos(q2)*cos(q3)*N.z)
+    assert express(C.x, A) == (cos(q3)*A.x + sin(q2)*sin(q3)*A.y -
+            sin(q3)*cos(q2)*A.z)
+    assert express(C.y, A) == (cos(q2)*A.y + sin(q2)*A.z)
+    assert express(C.z, A) == (sin(q3)*A.x - sin(q2)*cos(q3)*A.y +
+            cos(q2)*cos(q3)*A.z)
+    assert express(C.x, B) == (cos(q3)*B.x - sin(q3)*B.z)
+    assert express(C.y, B) == B.y
+    assert express(C.z, B) == (sin(q3)*B.x + cos(q3)*B.z)
+    assert express(C.x, C) == C.x
+    assert express(C.y, C) == C.y
+    assert express(C.z, C) == C.z == (C.z)
+
+    #  Check to make sure Vectors get converted back to UnitVectors
+    assert N.x == express((cos(q1)*A.x - sin(q1)*A.y), N).simplify()
+    assert N.y == express((sin(q1)*A.x + cos(q1)*A.y), N).simplify()
+    assert N.x == express((cos(q1)*B.x - sin(q1)*cos(q2)*B.y +
+            sin(q1)*sin(q2)*B.z), N).simplify()
+    assert N.y == express((sin(q1)*B.x + cos(q1)*cos(q2)*B.y -
+        sin(q2)*cos(q1)*B.z), N).simplify()
+    assert N.z == express((sin(q2)*B.y + cos(q2)*B.z), N).simplify()
+
+    """
+    These don't really test our code, they instead test the auto simplification
+    (or lack thereof) of SymPy.
+    assert N.x == express((
+            (cos(q1)*cos(q3)-sin(q1)*sin(q2)*sin(q3))*C.x -
+            sin(q1)*cos(q2)*C.y +
+            (sin(q3)*cos(q1)+sin(q1)*sin(q2)*cos(q3))*C.z), N)
+    assert N.y == express((
+            (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*C.x +
+            cos(q1)*cos(q2)*C.y +
+            (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*C.z), N)
+    assert N.z == express((-sin(q3)*cos(q2)*C.x + sin(q2)*C.y +
+            cos(q2)*cos(q3)*C.z), N)
+    """
+
+    assert A.x == express((cos(q1)*N.x + sin(q1)*N.y), A).simplify()
+    assert A.y == express((-sin(q1)*N.x + cos(q1)*N.y), A).simplify()
+
+    assert A.y == express((cos(q2)*B.y - sin(q2)*B.z), A).simplify()
+    assert A.z == express((sin(q2)*B.y + cos(q2)*B.z), A).simplify()
+
+    assert A.x == express((cos(q3)*C.x + sin(q3)*C.z), A).simplify()
+
+    # Tripsimp messes up here too.
+    #print express((sin(q2)*sin(q3)*C.x + cos(q2)*C.y -
+    #        sin(q2)*cos(q3)*C.z), A)
+    assert A.y == express((sin(q2)*sin(q3)*C.x + cos(q2)*C.y -
+            sin(q2)*cos(q3)*C.z), A).simplify()
+
+    assert A.z == express((-sin(q3)*cos(q2)*C.x + sin(q2)*C.y +
+            cos(q2)*cos(q3)*C.z), A).simplify()
+    assert B.x == express((cos(q1)*N.x + sin(q1)*N.y), B).simplify()
+    assert B.y == express((-sin(q1)*cos(q2)*N.x +
+            cos(q1)*cos(q2)*N.y + sin(q2)*N.z), B).simplify()
+
+    assert B.z == express((sin(q1)*sin(q2)*N.x -
+            sin(q2)*cos(q1)*N.y + cos(q2)*N.z), B).simplify()
+
+    assert B.y == express((cos(q2)*A.y + sin(q2)*A.z), B).simplify()
+    assert B.z == express((-sin(q2)*A.y + cos(q2)*A.z), B).simplify()
+    assert B.x == express((cos(q3)*C.x + sin(q3)*C.z), B).simplify()
+    assert B.z == express((-sin(q3)*C.x + cos(q3)*C.z), B).simplify()
+
+    """
+    assert C.x == express((
+            (cos(q1)*cos(q3)-sin(q1)*sin(q2)*sin(q3))*N.x +
+            (sin(q1)*cos(q3)+sin(q2)*sin(q3)*cos(q1))*N.y -
+                sin(q3)*cos(q2)*N.z), C)
+    assert C.y == express((
+            -sin(q1)*cos(q2)*N.x + cos(q1)*cos(q2)*N.y + sin(q2)*N.z), C)
+    assert C.z == express((
+            (sin(q3)*cos(q1)+sin(q1)*sin(q2)*cos(q3))*N.x +
+            (sin(q1)*sin(q3)-sin(q2)*cos(q1)*cos(q3))*N.y +
+            cos(q2)*cos(q3)*N.z), C)
+    """
+    assert C.x == express((cos(q3)*A.x + sin(q2)*sin(q3)*A.y -
+            sin(q3)*cos(q2)*A.z), C).simplify()
+    assert C.y == express((cos(q2)*A.y + sin(q2)*A.z), C).simplify()
+    assert C.z == express((sin(q3)*A.x - sin(q2)*cos(q3)*A.y +
+            cos(q2)*cos(q3)*A.z), C).simplify()
+    assert C.x == express((cos(q3)*B.x - sin(q3)*B.z), C).simplify()
+    assert C.z == express((sin(q3)*B.x + cos(q3)*B.z), C).simplify()
+
+
+def test_time_derivative():
+    #The use of time_derivative for calculations pertaining to scalar
+    #fields has been tested in test_coordinate_vars in test_essential.py
+    A = ReferenceFrame('A')
+    q = dynamicsymbols('q')
+    qd = dynamicsymbols('q', 1)
+    B = A.orientnew('B', 'Axis', [q, A.z])
+    d = A.x | A.x
+    assert time_derivative(d, B) == (-qd) * (A.y | A.x) + \
+           (-qd) * (A.x | A.y)
+    d1 = A.x | B.y
+    assert time_derivative(d1, A) == - qd*(A.x|B.x)
+    assert time_derivative(d1, B) == - qd*(A.y|B.y)
+    d2 = A.x | B.x
+    assert time_derivative(d2, A) == qd*(A.x|B.y)
+    assert time_derivative(d2, B) == - qd*(A.y|B.x)
+    d3 = A.x | B.z
+    assert time_derivative(d3, A) == 0
+    assert time_derivative(d3, B) == - qd*(A.y|B.z)
+    q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4')
+    q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1)
+    q1dd, q2dd, q3dd, q4dd = dynamicsymbols('q1 q2 q3 q4', 2)
+    C = B.orientnew('C', 'Axis', [q4, B.x])
+    v1 = q1 * A.z
+    v2 = q2*A.x + q3*B.y
+    v3 = q1*A.x + q2*A.y + q3*A.z
+    assert time_derivative(B.x, C) == 0
+    assert time_derivative(B.y, C) == - q4d*B.z
+    assert time_derivative(B.z, C) == q4d*B.y
+    assert time_derivative(v1, B) == q1d*A.z
+    assert time_derivative(v1, C) == - q1*sin(q)*q4d*A.x + \
+           q1*cos(q)*q4d*A.y + q1d*A.z
+    assert time_derivative(v2, A) == q2d*A.x - q3*qd*B.x + q3d*B.y
+    assert time_derivative(v2, C) == q2d*A.x - q2*qd*A.y + \
+           q2*sin(q)*q4d*A.z + q3d*B.y - q3*q4d*B.z
+    assert time_derivative(v3, B) == (q2*qd + q1d)*A.x + \
+           (-q1*qd + q2d)*A.y + q3d*A.z
+    assert time_derivative(d, C) == - qd*(A.y|A.x) + \
+           sin(q)*q4d*(A.z|A.x) - qd*(A.x|A.y) + sin(q)*q4d*(A.x|A.z)
+    raises(ValueError, lambda: time_derivative(B.x, C, order=0.5))
+    raises(ValueError, lambda: time_derivative(B.x, C, order=-1))
+
+
+def test_get_motion_methods():
+    #Initialization
+    t = dynamicsymbols._t
+    s1, s2, s3 = symbols('s1 s2 s3')
+    S1, S2, S3 = symbols('S1 S2 S3')
+    S4, S5, S6 = symbols('S4 S5 S6')
+    t1, t2 = symbols('t1 t2')
+    a, b, c = dynamicsymbols('a b c')
+    ad, bd, cd = dynamicsymbols('a b c', 1)
+    a2d, b2d, c2d = dynamicsymbols('a b c', 2)
+    v0 = S1*N.x + S2*N.y + S3*N.z
+    v01 = S4*N.x + S5*N.y + S6*N.z
+    v1 = s1*N.x + s2*N.y + s3*N.z
+    v2 = a*N.x + b*N.y + c*N.z
+    v2d = ad*N.x + bd*N.y + cd*N.z
+    v2dd = a2d*N.x + b2d*N.y + c2d*N.z
+    #Test position parameter
+    assert get_motion_params(frame = N) == (0, 0, 0)
+    assert get_motion_params(N, position=v1) == (0, 0, v1)
+    assert get_motion_params(N, position=v2) == (v2dd, v2d, v2)
+    #Test velocity parameter
+    assert get_motion_params(N, velocity=v1) == (0, v1, v1 * t)
+    assert get_motion_params(N, velocity=v1, position=v0, timevalue1=t1) == \
+           (0, v1, v0 + v1*(t - t1))
+    answer = get_motion_params(N, velocity=v1, position=v2, timevalue1=t1)
+    answer_expected = (0, v1, v1*t - v1*t1 + v2.subs(t, t1))
+    assert answer == answer_expected
+
+    answer = get_motion_params(N, velocity=v2, position=v0, timevalue1=t1)
+    integral_vector = Integral(a, (t, t1, t))*N.x + Integral(b, (t, t1, t))*N.y \
+            + Integral(c, (t, t1, t))*N.z
+    answer_expected = (v2d, v2, v0 + integral_vector)
+    assert answer == answer_expected
+
+    #Test acceleration parameter
+    assert get_motion_params(N, acceleration=v1) == \
+           (v1, v1 * t, v1 * t**2/2)
+    assert get_motion_params(N, acceleration=v1, velocity=v0,
+                          position=v2, timevalue1=t1, timevalue2=t2) == \
+           (v1, (v0 + v1*t - v1*t2),
+            -v0*t1 + v1*t**2/2 + v1*t2*t1 - \
+            v1*t1**2/2 + t*(v0 - v1*t2) + \
+            v2.subs(t, t1))
+    assert get_motion_params(N, acceleration=v1, velocity=v0,
+                             position=v01, timevalue1=t1, timevalue2=t2) == \
+           (v1, v0 + v1*t - v1*t2,
+            -v0*t1 + v01 + v1*t**2/2 + \
+            v1*t2*t1 - v1*t1**2/2 + \
+            t*(v0 - v1*t2))
+    answer = get_motion_params(N, acceleration=a*N.x, velocity=S1*N.x,
+                          position=S2*N.x, timevalue1=t1, timevalue2=t2)
+    i1 = Integral(a, (t, t2, t))
+    answer_expected = (a*N.x, (S1 + i1)*N.x, \
+        (S2 + Integral(S1 + i1, (t, t1, t)))*N.x)
+    assert answer == answer_expected
+
+
+def test_kin_eqs():
+    q0, q1, q2, q3 = dynamicsymbols('q0 q1 q2 q3')
+    q0d, q1d, q2d, q3d = dynamicsymbols('q0 q1 q2 q3', 1)
+    u1, u2, u3 = dynamicsymbols('u1 u2 u3')
+    ke = kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', 313)
+    assert ke == kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', '313')
+    kds = kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'quaternion')
+    assert kds == [-0.5 * q0 * u1 - 0.5 * q2 * u3 + 0.5 * q3 * u2 + q1d,
+            -0.5 * q0 * u2 + 0.5 * q1 * u3 - 0.5 * q3 * u1 + q2d,
+            -0.5 * q0 * u3 - 0.5 * q1 * u2 + 0.5 * q2 * u1 + q3d,
+            0.5 * q1 * u1 + 0.5 * q2 * u2 + 0.5 * q3 * u3 + q0d]
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2], 'quaternion'))
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'quaternion', '123'))
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'foo'))
+    raises(TypeError, lambda: kinematic_equations(u1, [q0, q1, q2, q3], 'quaternion'))
+    raises(TypeError, lambda: kinematic_equations([u1], [q0, q1, q2, q3], 'quaternion'))
+    raises(TypeError, lambda: kinematic_equations([u1, u2, u3], q0, 'quaternion'))
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'body'))
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'space'))
+    raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2], 'body', '222'))
+    assert kinematic_equations([0, 0, 0], [q0, q1, q2], 'space') == [S.Zero, S.Zero, S.Zero]
+
+
+def test_partial_velocity():
+    q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1 q2 q3 u1 u2 u3')
+    u4, u5 = dynamicsymbols('u4, u5')
+    r = symbols('r')
+
+    N = ReferenceFrame('N')
+    Y = N.orientnew('Y', 'Axis', [q1, N.z])
+    L = Y.orientnew('L', 'Axis', [q2, Y.x])
+    R = L.orientnew('R', 'Axis', [q3, L.y])
+    R.set_ang_vel(N, u1 * L.x + u2 * L.y + u3 * L.z)
+
+    C = Point('C')
+    C.set_vel(N, u4 * L.x + u5 * (Y.z ^ L.x))
+    Dmc = C.locatenew('Dmc', r * L.z)
+    Dmc.v2pt_theory(C, N, R)
+
+    vel_list = [Dmc.vel(N), C.vel(N), R.ang_vel_in(N)]
+    u_list = [u1, u2, u3, u4, u5]
+    assert (partial_velocity(vel_list, u_list, N) ==
+            [[- r*L.y, r*L.x, 0, L.x, cos(q2)*L.y - sin(q2)*L.z],
+            [0, 0, 0, L.x, cos(q2)*L.y - sin(q2)*L.z],
+            [L.x, L.y, L.z, 0, 0]])
+
+    # Make sure that partial velocities can be computed regardless if the
+    # orientation between frames is defined or not.
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    v = u4 * A.x + u5 * B.y
+    assert partial_velocity((v, ), (u4, u5), A) == [[A.x, B.y]]
+
+    raises(TypeError, lambda: partial_velocity(Dmc.vel(N), u_list, N))
+    raises(TypeError, lambda: partial_velocity(vel_list, u1, N))
+
+def test_dynamicsymbols():
+    #Tests to check the assumptions applied to dynamicsymbols
+    f1 = dynamicsymbols('f1')
+    f2 = dynamicsymbols('f2', real=True)
+    f3 = dynamicsymbols('f3', positive=True)
+    f4, f5 = dynamicsymbols('f4,f5', commutative=False)
+    f6 = dynamicsymbols('f6', integer=True)
+    assert f1.is_real is None
+    assert f2.is_real
+    assert f3.is_positive
+    assert f4*f5 != f5*f4
+    assert f6.is_integer

rl/Lib/site-packages/sympy/physics/vector/tests/test_output.py

@@ -0,0 +1,75 @@
+from sympy.core.singleton import S
+from sympy.physics.vector import Vector, ReferenceFrame, Dyadic
+from sympy.testing.pytest import raises
+
+A = ReferenceFrame('A')
+
+
+def test_output_type():
+    A = ReferenceFrame('A')
+    v = A.x + A.y
+    d = v | v
+    zerov = Vector(0)
+    zerod = Dyadic(0)
+
+    # dot products
+    assert isinstance(d & d, Dyadic)
+    assert isinstance(d & zerod, Dyadic)
+    assert isinstance(zerod & d, Dyadic)
+    assert isinstance(d & v, Vector)
+    assert isinstance(v & d, Vector)
+    assert isinstance(d & zerov, Vector)
+    assert isinstance(zerov & d, Vector)
+    raises(TypeError, lambda: d & S.Zero)
+    raises(TypeError, lambda: S.Zero & d)
+    raises(TypeError, lambda: d & 0)
+    raises(TypeError, lambda: 0 & d)
+    assert not isinstance(v & v, (Vector, Dyadic))
+    assert not isinstance(v & zerov, (Vector, Dyadic))
+    assert not isinstance(zerov & v, (Vector, Dyadic))
+    raises(TypeError, lambda: v & S.Zero)
+    raises(TypeError, lambda: S.Zero & v)
+    raises(TypeError, lambda: v & 0)
+    raises(TypeError, lambda: 0 & v)
+
+    # cross products
+    raises(TypeError, lambda: d ^ d)
+    raises(TypeError, lambda: d ^ zerod)
+    raises(TypeError, lambda: zerod ^ d)
+    assert isinstance(d ^ v, Dyadic)
+    assert isinstance(v ^ d, Dyadic)
+    assert isinstance(d ^ zerov, Dyadic)
+    assert isinstance(zerov ^ d, Dyadic)
+    assert isinstance(zerov ^ d, Dyadic)
+    raises(TypeError, lambda: d ^ S.Zero)
+    raises(TypeError, lambda: S.Zero ^ d)
+    raises(TypeError, lambda: d ^ 0)
+    raises(TypeError, lambda: 0 ^ d)
+    assert isinstance(v ^ v, Vector)
+    assert isinstance(v ^ zerov, Vector)
+    assert isinstance(zerov ^ v, Vector)
+    raises(TypeError, lambda: v ^ S.Zero)
+    raises(TypeError, lambda: S.Zero ^ v)
+    raises(TypeError, lambda: v ^ 0)
+    raises(TypeError, lambda: 0 ^ v)
+
+    # outer products
+    raises(TypeError, lambda: d | d)
+    raises(TypeError, lambda: d | zerod)
+    raises(TypeError, lambda: zerod | d)
+    raises(TypeError, lambda: d | v)
+    raises(TypeError, lambda: v | d)
+    raises(TypeError, lambda: d | zerov)
+    raises(TypeError, lambda: zerov | d)
+    raises(TypeError, lambda: zerov | d)
+    raises(TypeError, lambda: d | S.Zero)
+    raises(TypeError, lambda: S.Zero | d)
+    raises(TypeError, lambda: d | 0)
+    raises(TypeError, lambda: 0 | d)
+    assert isinstance(v | v, Dyadic)
+    assert isinstance(v | zerov, Dyadic)
+    assert isinstance(zerov | v, Dyadic)
+    raises(TypeError, lambda: v | S.Zero)
+    raises(TypeError, lambda: S.Zero | v)
+    raises(TypeError, lambda: v | 0)
+    raises(TypeError, lambda: 0 | v)

rl/Lib/site-packages/sympy/physics/vector/tests/test_point.py

@@ -0,0 +1,382 @@
+from sympy.physics.vector import dynamicsymbols, Point, ReferenceFrame
+from sympy.testing.pytest import raises, ignore_warnings
+import warnings
+
+def test_point_v1pt_theorys():
+    q, q2 = dynamicsymbols('q q2')
+    qd, q2d = dynamicsymbols('q q2', 1)
+    qdd, q2dd = dynamicsymbols('q q2', 2)
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    B.set_ang_vel(N, qd * B.z)
+    O = Point('O')
+    P = O.locatenew('P', B.x)
+    P.set_vel(B, 0)
+    O.set_vel(N, 0)
+    assert P.v1pt_theory(O, N, B) == qd * B.y
+    O.set_vel(N, N.x)
+    assert P.v1pt_theory(O, N, B) == N.x + qd * B.y
+    P.set_vel(B, B.z)
+    assert P.v1pt_theory(O, N, B) == B.z + N.x + qd * B.y
+
+
+def test_point_a1pt_theorys():
+    q, q2 = dynamicsymbols('q q2')
+    qd, q2d = dynamicsymbols('q q2', 1)
+    qdd, q2dd = dynamicsymbols('q q2', 2)
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    B.set_ang_vel(N, qd * B.z)
+    O = Point('O')
+    P = O.locatenew('P', B.x)
+    P.set_vel(B, 0)
+    O.set_vel(N, 0)
+    assert P.a1pt_theory(O, N, B) == -(qd**2) * B.x + qdd * B.y
+    P.set_vel(B, q2d * B.z)
+    assert P.a1pt_theory(O, N, B) == -(qd**2) * B.x + qdd * B.y + q2dd * B.z
+    O.set_vel(N, q2d * B.x)
+    assert P.a1pt_theory(O, N, B) == ((q2dd - qd**2) * B.x + (q2d * qd + qdd) * B.y +
+                               q2dd * B.z)
+
+
+def test_point_v2pt_theorys():
+    q = dynamicsymbols('q')
+    qd = dynamicsymbols('q', 1)
+    N = ReferenceFrame('N')
+    B = N.orientnew('B', 'Axis', [q, N.z])
+    O = Point('O')
+    P = O.locatenew('P', 0)
+    O.set_vel(N, 0)
+    assert P.v2pt_theory(O, N, B) == 0
+    P = O.locatenew('P', B.x)
+    assert P.v2pt_theory(O, N, B) == (qd * B.z ^ B.x)
+    O.set_vel(N, N.x)
+    assert P.v2pt_theory(O, N, B) == N.x + qd * B.y
+
+
+def test_point_a2pt_theorys():
+    q = dynamicsymbols('q')
+    qd = dynamicsymbols('q', 1)
+    qdd = dynamicsymbols('q', 2)
+    N = ReferenceFrame('N')
+    B = N.orientnew('B', 'Axis', [q, N.z])
+    O = Point('O')
+    P = O.locatenew('P', 0)
+    O.set_vel(N, 0)
+    assert P.a2pt_theory(O, N, B) == 0
+    P.set_pos(O, B.x)
+    assert P.a2pt_theory(O, N, B) == (-qd**2) * B.x + (qdd) * B.y
+
+
+def test_point_funcs():
+    q, q2 = dynamicsymbols('q q2')
+    qd, q2d = dynamicsymbols('q q2', 1)
+    qdd, q2dd = dynamicsymbols('q q2', 2)
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    B.set_ang_vel(N, 5 * B.y)
+    O = Point('O')
+    P = O.locatenew('P', q * B.x + q2 * B.y)
+    assert P.pos_from(O) == q * B.x + q2 * B.y
+    P.set_vel(B, qd * B.x + q2d * B.y)
+    assert P.vel(B) == qd * B.x + q2d * B.y
+    O.set_vel(N, 0)
+    assert O.vel(N) == 0
+    assert P.a1pt_theory(O, N, B) == ((-25 * q + qdd) * B.x + (q2dd) * B.y +
+                               (-10 * qd) * B.z)
+
+    B = N.orientnew('B', 'Axis', [q, N.z])
+    O = Point('O')
+    P = O.locatenew('P', 10 * B.x)
+    O.set_vel(N, 5 * N.x)
+    assert O.vel(N) == 5 * N.x
+    assert P.a2pt_theory(O, N, B) == (-10 * qd**2) * B.x + (10 * qdd) * B.y
+
+    B.set_ang_vel(N, 5 * B.y)
+    O = Point('O')
+    P = O.locatenew('P', q * B.x + q2 * B.y)
+    P.set_vel(B, qd * B.x + q2d * B.y)
+    O.set_vel(N, 0)
+    assert P.v1pt_theory(O, N, B) == qd * B.x + q2d * B.y - 5 * q * B.z
+
+
+def test_point_pos():
+    q = dynamicsymbols('q')
+    N = ReferenceFrame('N')
+    B = N.orientnew('B', 'Axis', [q, N.z])
+    O = Point('O')
+    P = O.locatenew('P', 10 * N.x + 5 * B.x)
+    assert P.pos_from(O) == 10 * N.x + 5 * B.x
+    Q = P.locatenew('Q', 10 * N.y + 5 * B.y)
+    assert Q.pos_from(P) == 10 * N.y + 5 * B.y
+    assert Q.pos_from(O) == 10 * N.x + 10 * N.y + 5 * B.x + 5 * B.y
+    assert O.pos_from(Q) == -10 * N.x - 10 * N.y - 5 * B.x - 5 * B.y
+
+def test_point_partial_velocity():
+
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+
+    p = Point('p')
+
+    u1, u2 = dynamicsymbols('u1, u2')
+
+    p.set_vel(N, u1 * A.x + u2 * N.y)
+
+    assert p.partial_velocity(N, u1) == A.x
+    assert p.partial_velocity(N, u1, u2) == (A.x, N.y)
+    raises(ValueError, lambda: p.partial_velocity(A, u1))
+
+def test_point_vel(): #Basic functionality
+    q1, q2 = dynamicsymbols('q1 q2')
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    Q = Point('Q')
+    O = Point('O')
+    Q.set_pos(O, q1 * N.x)
+    raises(ValueError , lambda: Q.vel(N)) # Velocity of O in N is not defined
+    O.set_vel(N, q2 * N.y)
+    assert O.vel(N) == q2 * N.y
+    raises(ValueError , lambda : O.vel(B)) #Velocity of O is not defined in B
+
+def test_auto_point_vel():
+    t = dynamicsymbols._t
+    q1, q2 = dynamicsymbols('q1 q2')
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    O = Point('O')
+    Q = Point('Q')
+    Q.set_pos(O, q1 * N.x)
+    O.set_vel(N, q2 * N.y)
+    assert Q.vel(N) == q1.diff(t) * N.x + q2 * N.y  # Velocity of Q using O
+    P1 = Point('P1')
+    P1.set_pos(O, q1 * B.x)
+    P2 = Point('P2')
+    P2.set_pos(P1, q2 * B.z)
+    raises(ValueError, lambda : P2.vel(B)) # O's velocity is defined in different frame, and no
+    #point in between has its velocity defined
+    raises(ValueError, lambda: P2.vel(N)) # Velocity of O not defined in N
+
+def test_auto_point_vel_multiple_point_path():
+    t = dynamicsymbols._t
+    q1, q2 = dynamicsymbols('q1 q2')
+    B = ReferenceFrame('B')
+    P = Point('P')
+    P.set_vel(B, q1 * B.x)
+    P1 = Point('P1')
+    P1.set_pos(P, q2 * B.y)
+    P1.set_vel(B, q1 * B.z)
+    P2 = Point('P2')
+    P2.set_pos(P1, q1 * B.z)
+    P3 = Point('P3')
+    P3.set_pos(P2, 10 * q1 * B.y)
+    assert P3.vel(B) == 10 * q1.diff(t) * B.y + (q1 + q1.diff(t)) * B.z
+
+def test_auto_vel_dont_overwrite():
+    t = dynamicsymbols._t
+    q1, q2, u1 = dynamicsymbols('q1, q2, u1')
+    N = ReferenceFrame('N')
+    P = Point('P1')
+    P.set_vel(N, u1 * N.x)
+    P1 = Point('P1')
+    P1.set_pos(P, q2 * N.y)
+    assert P1.vel(N) == q2.diff(t) * N.y + u1 * N.x
+    assert P.vel(N) == u1 * N.x
+    P1.set_vel(N, u1 * N.z)
+    assert P1.vel(N) == u1 * N.z
+
+def test_auto_point_vel_if_tree_has_vel_but_inappropriate_pos_vector():
+    q1, q2 = dynamicsymbols('q1 q2')
+    B = ReferenceFrame('B')
+    S = ReferenceFrame('S')
+    P = Point('P')
+    P.set_vel(B, q1 * B.x)
+    P1 = Point('P1')
+    P1.set_pos(P, S.y)
+    raises(ValueError, lambda : P1.vel(B)) # P1.pos_from(P) can't be expressed in B
+    raises(ValueError, lambda : P1.vel(S)) # P.vel(S) not defined
+
+def test_auto_point_vel_shortest_path():
+    t = dynamicsymbols._t
+    q1, q2, u1, u2 = dynamicsymbols('q1 q2 u1 u2')
+    B = ReferenceFrame('B')
+    P = Point('P')
+    P.set_vel(B, u1 * B.x)
+    P1 = Point('P1')
+    P1.set_pos(P, q2 * B.y)
+    P1.set_vel(B, q1 * B.z)
+    P2 = Point('P2')
+    P2.set_pos(P1, q1 * B.z)
+    P3 = Point('P3')
+    P3.set_pos(P2, 10 * q1 * B.y)
+    P4 = Point('P4')
+    P4.set_pos(P3, q1 * B.x)
+    O = Point('O')
+    O.set_vel(B, u2 * B.y)
+    O1 = Point('O1')
+    O1.set_pos(O, q2 * B.z)
+    P4.set_pos(O1, q1 * B.x + q2 * B.z)
+    with warnings.catch_warnings(): #There are two possible paths in this point tree, thus a warning is raised
+        warnings.simplefilter('error')
+        with ignore_warnings(UserWarning):
+            assert P4.vel(B) == q1.diff(t) * B.x + u2 * B.y + 2 * q2.diff(t) * B.z
+
+def test_auto_point_vel_connected_frames():
+    t = dynamicsymbols._t
+    q, q1, q2, u = dynamicsymbols('q q1 q2 u')
+    N = ReferenceFrame('N')
+    B = ReferenceFrame('B')
+    O = Point('O')
+    O.set_vel(N, u * N.x)
+    P = Point('P')
+    P.set_pos(O, q1 * N.x + q2 * B.y)
+    raises(ValueError, lambda: P.vel(N))
+    N.orient(B, 'Axis', (q, B.x))
+    assert P.vel(N) == (u + q1.diff(t)) * N.x + q2.diff(t) * B.y - q2 * q.diff(t) * B.z
+
+def test_auto_point_vel_multiple_paths_warning_arises():
+    q, u = dynamicsymbols('q u')
+    N = ReferenceFrame('N')
+    O = Point('O')
+    P = Point('P')
+    Q = Point('Q')
+    R = Point('R')
+    P.set_vel(N, u * N.x)
+    Q.set_vel(N, u *N.y)
+    R.set_vel(N, u * N.z)
+    O.set_pos(P, q * N.z)
+    O.set_pos(Q, q * N.y)
+    O.set_pos(R, q * N.x)
+    with warnings.catch_warnings(): #There are two possible paths in this point tree, thus a warning is raised
+        warnings.simplefilter("error")
+        raises(UserWarning ,lambda: O.vel(N))
+
+def test_auto_vel_cyclic_warning_arises():
+    P = Point('P')
+    P1 = Point('P1')
+    P2 = Point('P2')
+    P3 = Point('P3')
+    N = ReferenceFrame('N')
+    P.set_vel(N, N.x)
+    P1.set_pos(P, N.x)
+    P2.set_pos(P1, N.y)
+    P3.set_pos(P2, N.z)
+    P1.set_pos(P3, N.x + N.y)
+    with warnings.catch_warnings(): #The path is cyclic at P1, thus a warning is raised
+        warnings.simplefilter("error")
+        raises(UserWarning ,lambda: P2.vel(N))
+
+def test_auto_vel_cyclic_warning_msg():
+    P = Point('P')
+    P1 = Point('P1')
+    P2 = Point('P2')
+    P3 = Point('P3')
+    N = ReferenceFrame('N')
+    P.set_vel(N, N.x)
+    P1.set_pos(P, N.x)
+    P2.set_pos(P1, N.y)
+    P3.set_pos(P2, N.z)
+    P1.set_pos(P3, N.x + N.y)
+    with warnings.catch_warnings(record = True) as w: #The path is cyclic at P1, thus a warning is raised
+        warnings.simplefilter("always")
+        P2.vel(N)
+        msg = str(w[-1].message).replace("\n", " ")
+        assert issubclass(w[-1].category, UserWarning)
+        assert 'Kinematic loops are defined among the positions of points. This is likely not desired and may cause errors in your calculations.' in msg
+
+def test_auto_vel_multiple_path_warning_msg():
+    N = ReferenceFrame('N')
+    O = Point('O')
+    P = Point('P')
+    Q = Point('Q')
+    P.set_vel(N, N.x)
+    Q.set_vel(N, N.y)
+    O.set_pos(P, N.z)
+    O.set_pos(Q, N.y)
+    with warnings.catch_warnings(record = True) as w: #There are two possible paths in this point tree, thus a warning is raised
+        warnings.simplefilter("always")
+        O.vel(N)
+        msg = str(w[-1].message).replace("\n", " ")
+        assert issubclass(w[-1].category, UserWarning)
+        assert 'Velocity' in msg
+        assert 'automatically calculated based on point' in msg
+        assert 'Velocities from these points are not necessarily the same. This may cause errors in your calculations.' in msg
+
+def test_auto_vel_derivative():
+    q1, q2 = dynamicsymbols('q1:3')
+    u1, u2 = dynamicsymbols('u1:3', 1)
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+    B.orient_axis(A, A.z, q1)
+    B.set_ang_vel(A, u1 * A.z)
+    C.orient_axis(B, B.z, q2)
+    C.set_ang_vel(B, u2 * B.z)
+
+    Am = Point('Am')
+    Am.set_vel(A, 0)
+    Bm = Point('Bm')
+    Bm.set_pos(Am, B.x)
+    Bm.set_vel(B, 0)
+    Bm.set_vel(C, 0)
+    Cm = Point('Cm')
+    Cm.set_pos(Bm, C.x)
+    Cm.set_vel(C, 0)
+    temp = Cm._vel_dict.copy()
+    assert Cm.vel(A) == (u1 * B.y + (u1 + u2) * C.y)
+    Cm._vel_dict = temp
+    Cm.v2pt_theory(Bm, B, C)
+    assert Cm.vel(A) == (u1 * B.y + (u1 + u2) * C.y)
+
+def test_auto_point_acc_zero_vel():
+    N = ReferenceFrame('N')
+    O = Point('O')
+    O.set_vel(N, 0)
+    assert O.acc(N) == 0 * N.x
+
+def test_auto_point_acc_compute_vel():
+    t = dynamicsymbols._t
+    q1 = dynamicsymbols('q1')
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+    A.orient_axis(N, N.z, q1)
+
+    O = Point('O')
+    O.set_vel(N, 0)
+    P = Point('P')
+    P.set_pos(O, A.x)
+    assert P.acc(N) == -q1.diff(t) ** 2 * A.x + q1.diff(t, 2) * A.y
+
+def test_auto_acc_derivative():
+    # Tests whether the Point.acc method gives the correct acceleration of the
+    # end point of two linkages in series, while getting minimal information.
+    q1, q2 = dynamicsymbols('q1:3')
+    u1, u2 = dynamicsymbols('q1:3', 1)
+    v1, v2 = dynamicsymbols('q1:3', 2)
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    C = ReferenceFrame('C')
+    B.orient_axis(A, A.z, q1)
+    C.orient_axis(B, B.z, q2)
+
+    Am = Point('Am')
+    Am.set_vel(A, 0)
+    Bm = Point('Bm')
+    Bm.set_pos(Am, B.x)
+    Bm.set_vel(B, 0)
+    Bm.set_vel(C, 0)
+    Cm = Point('Cm')
+    Cm.set_pos(Bm, C.x)
+    Cm.set_vel(C, 0)
+
+    # Copy dictionaries to later check the calculation using the 2pt_theories
+    Bm_vel_dict, Cm_vel_dict = Bm._vel_dict.copy(), Cm._vel_dict.copy()
+    Bm_acc_dict, Cm_acc_dict = Bm._acc_dict.copy(), Cm._acc_dict.copy()
+    check = -u1 ** 2 * B.x + v1 * B.y - (u1 + u2) ** 2 * C.x + (v1 + v2) * C.y
+    assert Cm.acc(A) == check
+    Bm._vel_dict, Cm._vel_dict = Bm_vel_dict, Cm_vel_dict
+    Bm._acc_dict, Cm._acc_dict = Bm_acc_dict, Cm_acc_dict
+    Bm.v2pt_theory(Am, A, B)
+    Cm.v2pt_theory(Bm, A, C)
+    Bm.a2pt_theory(Am, A, B)
+    assert Cm.a2pt_theory(Bm, A, C) == check

rl/Lib/site-packages/sympy/physics/vector/tests/test_printing.py

@@ -0,0 +1,353 @@
+# -*- coding: utf-8 -*-
+
+from sympy.core.function import Function
+from sympy.core.symbol import symbols
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.trigonometric import (asin, cos, sin)
+from sympy.physics.vector import ReferenceFrame, dynamicsymbols, Dyadic
+from sympy.physics.vector.printing import (VectorLatexPrinter, vpprint,
+                                           vsprint, vsstrrepr, vlatex)
+
+
+a, b, c = symbols('a, b, c')
+alpha, omega, beta = dynamicsymbols('alpha, omega, beta')
+
+A = ReferenceFrame('A')
+N = ReferenceFrame('N')
+
+v = a ** 2 * N.x + b * N.y + c * sin(alpha) * N.z
+w = alpha * N.x + sin(omega) * N.y + alpha * beta * N.z
+ww = alpha * N.x + asin(omega) * N.y - alpha.diff() * beta * N.z
+o = a/b * N.x + (c+b)/a * N.y + c**2/b * N.z
+
+y = a ** 2 * (N.x | N.y) + b * (N.y | N.y) + c * sin(alpha) * (N.z | N.y)
+x = alpha * (N.x | N.x) + sin(omega) * (N.y | N.z) + alpha * beta * (N.z | N.x)
+xx = N.x | (-N.y - N.z)
+xx2 = N.x | (N.y + N.z)
+
+def ascii_vpretty(expr):
+    return vpprint(expr, use_unicode=False, wrap_line=False)
+
+
+def unicode_vpretty(expr):
+    return vpprint(expr, use_unicode=True, wrap_line=False)
+
+
+def test_latex_printer():
+    r = Function('r')('t')
+    assert VectorLatexPrinter().doprint(r ** 2) == "r^{2}"
+    r2 = Function('r^2')('t')
+    assert VectorLatexPrinter().doprint(r2.diff()) == r'\dot{r^{2}}'
+    ra = Function('r__a')('t')
+    assert VectorLatexPrinter().doprint(ra.diff().diff()) == r'\ddot{r^{a}}'
+
+
+def test_vector_pretty_print():
+
+    # TODO : The unit vectors should print with subscripts but they just
+    # print as `n_x` instead of making `x` a subscript with unicode.
+
+    # TODO : The pretty print division does not print correctly here:
+    # w = alpha * N.x + sin(omega) * N.y + alpha / beta * N.z
+
+    expected = """\
+ 2                               \n\
+a  n_x + b n_y + c*sin(alpha) n_z\
+"""
+    uexpected = """\
+ 2                           \n\
+a  n_x + b n_y + c⋅sin(α) n_z\
+"""
+
+    assert ascii_vpretty(v) == expected
+    assert unicode_vpretty(v) == uexpected
+
+    expected = 'alpha n_x + sin(omega) n_y + alpha*beta n_z'
+    uexpected = 'α n_x + sin(ω) n_y + α⋅β n_z'
+
+    assert ascii_vpretty(w) == expected
+    assert unicode_vpretty(w) == uexpected
+
+    expected = """\
+                     2    \n\
+a       b + c       c     \n\
+- n_x + ----- n_y + -- n_z\n\
+b         a         b     \
+"""
+    uexpected = """\
+                     2    \n\
+a       b + c       c     \n\
+─ n_x + ───── n_y + ── n_z\n\
+b         a         b     \
+"""
+
+    assert ascii_vpretty(o) == expected
+    assert unicode_vpretty(o) == uexpected
+
+    # https://github.com/sympy/sympy/issues/26731
+    assert ascii_vpretty(-A.x) == '-a_x'
+    assert unicode_vpretty(-A.x) == '-a_x'
+
+    # https://github.com/sympy/sympy/issues/26799
+    assert ascii_vpretty(0*A.x) == '0'
+    assert unicode_vpretty(0*A.x) == '0'
+
+
+def test_vector_latex():
+
+    a, b, c, d, omega = symbols('a, b, c, d, omega')
+
+    v = (a ** 2 + b / c) * A.x + sqrt(d) * A.y + cos(omega) * A.z
+
+    assert vlatex(v) == (r'(a^{2} + \frac{b}{c})\mathbf{\hat{a}_x} + '
+                         r'\sqrt{d}\mathbf{\hat{a}_y} + '
+                         r'\cos{\left(\omega \right)}'
+                         r'\mathbf{\hat{a}_z}')
+
+    theta, omega, alpha, q = dynamicsymbols('theta, omega, alpha, q')
+
+    v = theta * A.x + omega * omega * A.y + (q * alpha) * A.z
+
+    assert vlatex(v) == (r'\theta\mathbf{\hat{a}_x} + '
+                         r'\omega^{2}\mathbf{\hat{a}_y} + '
+                         r'\alpha q\mathbf{\hat{a}_z}')
+
+    phi1, phi2, phi3 = dynamicsymbols('phi1, phi2, phi3')
+    theta1, theta2, theta3 = symbols('theta1, theta2, theta3')
+
+    v = (sin(theta1) * A.x +
+         cos(phi1) * cos(phi2) * A.y +
+         cos(theta1 + phi3) * A.z)
+
+    assert vlatex(v) == (r'\sin{\left(\theta_{1} \right)}'
+                         r'\mathbf{\hat{a}_x} + \cos{'
+                         r'\left(\phi_{1} \right)} \cos{'
+                         r'\left(\phi_{2} \right)}\mathbf{\hat{a}_y} + '
+                         r'\cos{\left(\theta_{1} + '
+                         r'\phi_{3} \right)}\mathbf{\hat{a}_z}')
+
+    N = ReferenceFrame('N')
+
+    a, b, c, d, omega = symbols('a, b, c, d, omega')
+
+    v = (a ** 2 + b / c) * N.x + sqrt(d) * N.y + cos(omega) * N.z
+
+    expected = (r'(a^{2} + \frac{b}{c})\mathbf{\hat{n}_x} + '
+                r'\sqrt{d}\mathbf{\hat{n}_y} + '
+                r'\cos{\left(\omega \right)}'
+                r'\mathbf{\hat{n}_z}')
+
+    assert vlatex(v) == expected
+
+    # Try custom unit vectors.
+
+    N = ReferenceFrame('N', latexs=(r'\hat{i}', r'\hat{j}', r'\hat{k}'))
+
+    v = (a ** 2 + b / c) * N.x + sqrt(d) * N.y + cos(omega) * N.z
+
+    expected = (r'(a^{2} + \frac{b}{c})\hat{i} + '
+                r'\sqrt{d}\hat{j} + '
+                r'\cos{\left(\omega \right)}\hat{k}')
+    assert vlatex(v) == expected
+
+    expected = r'\alpha\mathbf{\hat{n}_x} + \operatorname{asin}{\left(\omega ' \
+        r'\right)}\mathbf{\hat{n}_y} -  \beta \dot{\alpha}\mathbf{\hat{n}_z}'
+    assert vlatex(ww) == expected
+
+    expected = r'- \mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} - ' \
+        r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_z}'
+    assert vlatex(xx) == expected
+
+    expected = r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} + ' \
+        r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_z}'
+    assert vlatex(xx2) == expected
+
+
+def test_vector_latex_arguments():
+    assert vlatex(N.x * 3.0, full_prec=False) == r'3.0\mathbf{\hat{n}_x}'
+    assert vlatex(N.x * 3.0, full_prec=True) == r'3.00000000000000\mathbf{\hat{n}_x}'
+
+
+def test_vector_latex_with_functions():
+
+    N = ReferenceFrame('N')
+
+    omega, alpha = dynamicsymbols('omega, alpha')
+
+    v = omega.diff() * N.x
+
+    assert vlatex(v) == r'\dot{\omega}\mathbf{\hat{n}_x}'
+
+    v = omega.diff() ** alpha * N.x
+
+    assert vlatex(v) == (r'\dot{\omega}^{\alpha}'
+                          r'\mathbf{\hat{n}_x}')
+
+
+def test_dyadic_pretty_print():
+
+    expected = """\
+ 2
+a  n_x|n_y + b n_y|n_y + c*sin(alpha) n_z|n_y\
+"""
+
+    uexpected = """\
+ 2
+a  n_x⊗n_y + b n_y⊗n_y + c⋅sin(α) n_z⊗n_y\
+"""
+    assert ascii_vpretty(y) == expected
+    assert unicode_vpretty(y) == uexpected
+
+    expected = 'alpha n_x|n_x + sin(omega) n_y|n_z + alpha*beta n_z|n_x'
+    uexpected = 'α n_x⊗n_x + sin(ω) n_y⊗n_z + α⋅β n_z⊗n_x'
+    assert ascii_vpretty(x) == expected
+    assert unicode_vpretty(x) == uexpected
+
+    assert ascii_vpretty(Dyadic([])) == '0'
+    assert unicode_vpretty(Dyadic([])) == '0'
+
+    assert ascii_vpretty(xx) == '- n_x|n_y - n_x|n_z'
+    assert unicode_vpretty(xx) == '- n_x⊗n_y - n_x⊗n_z'
+
+    assert ascii_vpretty(xx2) == 'n_x|n_y + n_x|n_z'
+    assert unicode_vpretty(xx2) == 'n_x⊗n_y + n_x⊗n_z'
+
+
+def test_dyadic_latex():
+
+    expected = (r'a^{2}\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} + '
+                r'b\mathbf{\hat{n}_y}\otimes \mathbf{\hat{n}_y} + '
+                r'c \sin{\left(\alpha \right)}'
+                r'\mathbf{\hat{n}_z}\otimes \mathbf{\hat{n}_y}')
+
+    assert vlatex(y) == expected
+
+    expected = (r'\alpha\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_x} + '
+                r'\sin{\left(\omega \right)}\mathbf{\hat{n}_y}'
+                r'\otimes \mathbf{\hat{n}_z} + '
+                r'\alpha \beta\mathbf{\hat{n}_z}\otimes \mathbf{\hat{n}_x}')
+
+    assert vlatex(x) == expected
+
+    assert vlatex(Dyadic([])) == '0'
+
+
+def test_dyadic_str():
+    assert vsprint(Dyadic([])) == '0'
+    assert vsprint(y) == 'a**2*(N.x|N.y) + b*(N.y|N.y) + c*sin(alpha)*(N.z|N.y)'
+    assert vsprint(x) == 'alpha*(N.x|N.x) + sin(omega)*(N.y|N.z) + alpha*beta*(N.z|N.x)'
+    assert vsprint(ww) == "alpha*N.x + asin(omega)*N.y - beta*alpha'*N.z"
+    assert vsprint(xx) == '- (N.x|N.y) - (N.x|N.z)'
+    assert vsprint(xx2) == '(N.x|N.y) + (N.x|N.z)'
+
+
+def test_vlatex(): # vlatex is broken #12078
+    from sympy.physics.vector import vlatex
+
+    x = symbols('x')
+    J = symbols('J')
+
+    f = Function('f')
+    g = Function('g')
+    h = Function('h')
+
+    expected = r'J \left(\frac{d}{d x} g{\left(x \right)} - \frac{d}{d x} h{\left(x \right)}\right)'
+
+    expr = J*f(x).diff(x).subs(f(x), g(x)-h(x))
+
+    assert vlatex(expr) == expected
+
+
+def test_issue_13354():
+    """
+    Test for proper pretty printing of physics vectors with ADD
+    instances in arguments.
+
+    Test is exactly the one suggested in the original bug report by
+    @moorepants.
+    """
+
+    a, b, c = symbols('a, b, c')
+    A = ReferenceFrame('A')
+    v = a * A.x + b * A.y + c * A.z
+    w = b * A.x + c * A.y + a * A.z
+    z = w + v
+
+    expected = """(a + b) a_x + (b + c) a_y + (a + c) a_z"""
+
+    assert ascii_vpretty(z) == expected
+
+
+def test_vector_derivative_printing():
+    # First order
+    v = omega.diff() * N.x
+    assert unicode_vpretty(v) == 'ω̇ n_x'
+    assert ascii_vpretty(v) == "omega'(t) n_x"
+
+    # Second order
+    v = omega.diff().diff() * N.x
+
+    assert vlatex(v) == r'\ddot{\omega}\mathbf{\hat{n}_x}'
+    assert unicode_vpretty(v) == 'ω̈ n_x'
+    assert ascii_vpretty(v) == "omega''(t) n_x"
+
+    # Third order
+    v = omega.diff().diff().diff() * N.x
+
+    assert vlatex(v) == r'\dddot{\omega}\mathbf{\hat{n}_x}'
+    assert unicode_vpretty(v) == 'ω⃛ n_x'
+    assert ascii_vpretty(v) == "omega'''(t) n_x"
+
+    # Fourth order
+    v = omega.diff().diff().diff().diff() * N.x
+
+    assert vlatex(v) == r'\ddddot{\omega}\mathbf{\hat{n}_x}'
+    assert unicode_vpretty(v) == 'ω⃜ n_x'
+    assert ascii_vpretty(v) == "omega''''(t) n_x"
+
+    # Fifth order
+    v = omega.diff().diff().diff().diff().diff() * N.x
+
+    assert vlatex(v) == r'\frac{d^{5}}{d t^{5}} \omega\mathbf{\hat{n}_x}'
+    expected = '''\
+ 5            \n\
+d             \n\
+---(omega) n_x\n\
+  5           \n\
+dt            \
+'''
+    uexpected = '''\
+ 5        \n\
+d         \n\
+───(ω) n_x\n\
+  5       \n\
+dt        \
+'''
+    assert unicode_vpretty(v) == uexpected
+    assert ascii_vpretty(v) == expected
+
+
+def test_vector_str_printing():
+    assert vsprint(w) == 'alpha*N.x + sin(omega)*N.y + alpha*beta*N.z'
+    assert vsprint(omega.diff() * N.x) == "omega'*N.x"
+    assert vsstrrepr(w) == 'alpha*N.x + sin(omega)*N.y + alpha*beta*N.z'
+
+
+def test_vector_str_arguments():
+    assert vsprint(N.x * 3.0, full_prec=False) == '3.0*N.x'
+    assert vsprint(N.x * 3.0, full_prec=True) == '3.00000000000000*N.x'
+
+
+def test_issue_14041():
+    import sympy.physics.mechanics as me
+
+    A_frame = me.ReferenceFrame('A')
+    thetad, phid = me.dynamicsymbols('theta, phi', 1)
+    L = symbols('L')
+
+    assert vlatex(L*(phid + thetad)**2*A_frame.x) == \
+        r"L \left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}"
+    assert vlatex((phid + thetad)**2*A_frame.x) == \
+        r"\left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}"
+    assert vlatex((phid*thetad)**a*A_frame.x) == \
+        r"\left(\dot{\phi} \dot{\theta}\right)^{a}\mathbf{\hat{a}_x}"

rl/Lib/site-packages/sympy/physics/vector/tests/test_vector.py

@@ -0,0 +1,274 @@
+from sympy.core.numbers import (Float, pi)
+from sympy.core.symbol import symbols
+from sympy.core.sorting import ordered
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix
+from sympy.physics.vector import ReferenceFrame, Vector, dynamicsymbols, dot
+from sympy.physics.vector.vector import VectorTypeError
+from sympy.abc import x, y, z
+from sympy.testing.pytest import raises
+
+A = ReferenceFrame('A')
+
+
+def test_free_dynamicsymbols():
+    A, B, C, D = symbols('A, B, C, D', cls=ReferenceFrame)
+    a, b, c, d, e, f = dynamicsymbols('a, b, c, d, e, f')
+    B.orient_axis(A, a, A.x)
+    C.orient_axis(B, b, B.y)
+    D.orient_axis(C, c, C.x)
+
+    v = d*D.x + e*D.y + f*D.z
+
+    assert set(ordered(v.free_dynamicsymbols(A))) == {a, b, c, d, e, f}
+    assert set(ordered(v.free_dynamicsymbols(B))) == {b, c, d, e, f}
+    assert set(ordered(v.free_dynamicsymbols(C))) == {c, d, e, f}
+    assert set(ordered(v.free_dynamicsymbols(D))) == {d, e, f}
+
+
+def test_Vector():
+    assert A.x != A.y
+    assert A.y != A.z
+    assert A.z != A.x
+
+    assert A.x + 0 == A.x
+
+    v1 = x*A.x + y*A.y + z*A.z
+    v2 = x**2*A.x + y**2*A.y + z**2*A.z
+    v3 = v1 + v2
+    v4 = v1 - v2
+
+    assert isinstance(v1, Vector)
+    assert dot(v1, A.x) == x
+    assert dot(v1, A.y) == y
+    assert dot(v1, A.z) == z
+
+    assert isinstance(v2, Vector)
+    assert dot(v2, A.x) == x**2
+    assert dot(v2, A.y) == y**2
+    assert dot(v2, A.z) == z**2
+
+    assert isinstance(v3, Vector)
+    # We probably shouldn't be using simplify in dot...
+    assert dot(v3, A.x) == x**2 + x
+    assert dot(v3, A.y) == y**2 + y
+    assert dot(v3, A.z) == z**2 + z
+
+    assert isinstance(v4, Vector)
+    # We probably shouldn't be using simplify in dot...
+    assert dot(v4, A.x) == x - x**2
+    assert dot(v4, A.y) == y - y**2
+    assert dot(v4, A.z) == z - z**2
+
+    assert v1.to_matrix(A) == Matrix([[x], [y], [z]])
+    q = symbols('q')
+    B = A.orientnew('B', 'Axis', (q, A.x))
+    assert v1.to_matrix(B) == Matrix([[x],
+                                      [ y * cos(q) + z * sin(q)],
+                                      [-y * sin(q) + z * cos(q)]])
+
+    #Test the separate method
+    B = ReferenceFrame('B')
+    v5 = x*A.x + y*A.y + z*B.z
+    assert Vector(0).separate() == {}
+    assert v1.separate() == {A: v1}
+    assert v5.separate() == {A: x*A.x + y*A.y, B: z*B.z}
+
+    #Test the free_symbols property
+    v6 = x*A.x + y*A.y + z*A.z
+    assert v6.free_symbols(A) == {x,y,z}
+
+    raises(TypeError, lambda: v3.applyfunc(v1))
+
+
+def test_Vector_diffs():
+    q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4')
+    q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1)
+    q1dd, q2dd, q3dd, q4dd = dynamicsymbols('q1 q2 q3 q4', 2)
+    N = ReferenceFrame('N')
+    A = N.orientnew('A', 'Axis', [q3, N.z])
+    B = A.orientnew('B', 'Axis', [q2, A.x])
+    v1 = q2 * A.x + q3 * N.y
+    v2 = q3 * B.x + v1
+    v3 = v1.dt(B)
+    v4 = v2.dt(B)
+    v5 = q1*A.x + q2*A.y + q3*A.z
+
+    assert v1.dt(N) == q2d * A.x + q2 * q3d * A.y + q3d * N.y
+    assert v1.dt(A) == q2d * A.x + q3 * q3d * N.x + q3d * N.y
+    assert v1.dt(B) == (q2d * A.x + q3 * q3d * N.x + q3d *
+                        N.y - q3 * cos(q3) * q2d * N.z)
+    assert v2.dt(N) == (q2d * A.x + (q2 + q3) * q3d * A.y + q3d * B.x + q3d *
+                        N.y)
+    assert v2.dt(A) == q2d * A.x + q3d * B.x + q3 * q3d * N.x + q3d * N.y
+    assert v2.dt(B) == (q2d * A.x + q3d * B.x + q3 * q3d * N.x + q3d * N.y -
+                        q3 * cos(q3) * q2d * N.z)
+    assert v3.dt(N) == (q2dd * A.x + q2d * q3d * A.y + (q3d**2 + q3 * q3dd) *
+                        N.x + q3dd * N.y + (q3 * sin(q3) * q2d * q3d -
+                        cos(q3) * q2d * q3d - q3 * cos(q3) * q2dd) * N.z)
+    assert v3.dt(A) == (q2dd * A.x + (2 * q3d**2 + q3 * q3dd) * N.x + (q3dd -
+                        q3 * q3d**2) * N.y + (q3 * sin(q3) * q2d * q3d -
+                        cos(q3) * q2d * q3d - q3 * cos(q3) * q2dd) * N.z)
+    assert (v3.dt(B) - (q2dd*A.x - q3*cos(q3)*q2d**2*A.y + (2*q3d**2 +
+        q3*q3dd)*N.x + (q3dd - q3*q3d**2)*N.y + (2*q3*sin(q3)*q2d*q3d -
+        2*cos(q3)*q2d*q3d - q3*cos(q3)*q2dd)*N.z)).express(B).simplify() == 0
+    assert v4.dt(N) == (q2dd * A.x + q3d * (q2d + q3d) * A.y + q3dd * B.x +
+                        (q3d**2 + q3 * q3dd) * N.x + q3dd * N.y + (q3 *
+                        sin(q3) * q2d * q3d - cos(q3) * q2d * q3d - q3 *
+                        cos(q3) * q2dd) * N.z)
+    assert v4.dt(A) == (q2dd * A.x + q3dd * B.x + (2 * q3d**2 + q3 * q3dd) *
+                        N.x + (q3dd - q3 * q3d**2) * N.y + (q3 * sin(q3) *
+                        q2d * q3d - cos(q3) * q2d * q3d - q3 * cos(q3) *
+                        q2dd) * N.z)
+    assert (v4.dt(B) - (q2dd*A.x - q3*cos(q3)*q2d**2*A.y + q3dd*B.x +
+                        (2*q3d**2 + q3*q3dd)*N.x + (q3dd - q3*q3d**2)*N.y +
+                        (2*q3*sin(q3)*q2d*q3d - 2*cos(q3)*q2d*q3d -
+                         q3*cos(q3)*q2dd)*N.z)).express(B).simplify() == 0
+    assert v5.dt(B) == q1d*A.x + (q3*q2d + q2d)*A.y + (-q2*q2d + q3d)*A.z
+    assert v5.dt(A) == q1d*A.x + q2d*A.y + q3d*A.z
+    assert v5.dt(N) == (-q2*q3d + q1d)*A.x + (q1*q3d + q2d)*A.y + q3d*A.z
+    assert v3.diff(q1d, N) == 0
+    assert v3.diff(q2d, N) == A.x - q3 * cos(q3) * N.z
+    assert v3.diff(q3d, N) == q3 * N.x + N.y
+    assert v3.diff(q1d, A) == 0
+    assert v3.diff(q2d, A) == A.x - q3 * cos(q3) * N.z
+    assert v3.diff(q3d, A) == q3 * N.x + N.y
+    assert v3.diff(q1d, B) == 0
+    assert v3.diff(q2d, B) == A.x - q3 * cos(q3) * N.z
+    assert v3.diff(q3d, B) == q3 * N.x + N.y
+    assert v4.diff(q1d, N) == 0
+    assert v4.diff(q2d, N) == A.x - q3 * cos(q3) * N.z
+    assert v4.diff(q3d, N) == B.x + q3 * N.x + N.y
+    assert v4.diff(q1d, A) == 0
+    assert v4.diff(q2d, A) == A.x - q3 * cos(q3) * N.z
+    assert v4.diff(q3d, A) == B.x + q3 * N.x + N.y
+    assert v4.diff(q1d, B) == 0
+    assert v4.diff(q2d, B) == A.x - q3 * cos(q3) * N.z
+    assert v4.diff(q3d, B) == B.x + q3 * N.x + N.y
+
+    # diff() should only express vector components in the derivative frame if
+    # the orientation of the component's frame depends on the variable
+    v6 = q2**2*N.y + q2**2*A.y + q2**2*B.y
+    # already expressed in N
+    n_measy = 2*q2
+    # A_C_N does not depend on q2, so don't express in N
+    a_measy = 2*q2
+    # B_C_N depends on q2, so express in N
+    b_measx = (q2**2*B.y).dot(N.x).diff(q2)
+    b_measy = (q2**2*B.y).dot(N.y).diff(q2)
+    b_measz = (q2**2*B.y).dot(N.z).diff(q2)
+    n_comp, a_comp = v6.diff(q2, N).args
+    assert len(v6.diff(q2, N).args) == 2  # only N and A parts
+    assert n_comp[1] == N
+    assert a_comp[1] == A
+    assert n_comp[0] == Matrix([b_measx, b_measy + n_measy, b_measz])
+    assert a_comp[0] == Matrix([0, a_measy, 0])
+
+
+def test_vector_var_in_dcm():
+
+    N = ReferenceFrame('N')
+    A = ReferenceFrame('A')
+    B = ReferenceFrame('B')
+    u1, u2, u3, u4 = dynamicsymbols('u1 u2 u3 u4')
+
+    v = u1 * u2 * A.x + u3 * N.y + u4**2 * N.z
+
+    assert v.diff(u1, N, var_in_dcm=False) == u2 * A.x
+    assert v.diff(u1, A, var_in_dcm=False) == u2 * A.x
+    assert v.diff(u3, N, var_in_dcm=False) == N.y
+    assert v.diff(u3, A, var_in_dcm=False) == N.y
+    assert v.diff(u3, B, var_in_dcm=False) == N.y
+    assert v.diff(u4, N, var_in_dcm=False) == 2 * u4 * N.z
+
+    raises(ValueError, lambda: v.diff(u1, N))
+
+
+def test_vector_simplify():
+    x, y, z, k, n, m, w, f, s, A = symbols('x, y, z, k, n, m, w, f, s, A')
+    N = ReferenceFrame('N')
+
+    test1 = (1 / x + 1 / y) * N.x
+    assert (test1 & N.x) != (x + y) / (x * y)
+    test1 = test1.simplify()
+    assert (test1 & N.x) == (x + y) / (x * y)
+
+    test2 = (A**2 * s**4 / (4 * pi * k * m**3)) * N.x
+    test2 = test2.simplify()
+    assert (test2 & N.x) == (A**2 * s**4 / (4 * pi * k * m**3))
+
+    test3 = ((4 + 4 * x - 2 * (2 + 2 * x)) / (2 + 2 * x)) * N.x
+    test3 = test3.simplify()
+    assert (test3 & N.x) == 0
+
+    test4 = ((-4 * x * y**2 - 2 * y**3 - 2 * x**2 * y) / (x + y)**2) * N.x
+    test4 = test4.simplify()
+    assert (test4 & N.x) == -2 * y
+
+
+def test_vector_evalf():
+    a, b = symbols('a b')
+    v = pi * A.x
+    assert v.evalf(2) == Float('3.1416', 2) * A.x
+    v = pi * A.x + 5 * a * A.y - b * A.z
+    assert v.evalf(3) == Float('3.1416', 3) * A.x + Float('5', 3) * a * A.y - b * A.z
+    assert v.evalf(5, subs={a: 1.234, b:5.8973}) == Float('3.1415926536', 5) * A.x + Float('6.17', 5) * A.y - Float('5.8973', 5) * A.z
+
+
+def test_vector_angle():
+    A = ReferenceFrame('A')
+    v1 = A.x + A.y
+    v2 = A.z
+    assert v1.angle_between(v2) == pi/2
+    B = ReferenceFrame('B')
+    B.orient_axis(A, A.x, pi)
+    v3 = A.x
+    v4 = B.x
+    assert v3.angle_between(v4) == 0
+
+
+def test_vector_xreplace():
+    x, y, z = symbols('x y z')
+    v = x**2 * A.x + x*y * A.y + x*y*z * A.z
+    assert v.xreplace({x : cos(x)}) == cos(x)**2 * A.x + y*cos(x) * A.y + y*z*cos(x) * A.z
+    assert v.xreplace({x*y : pi}) == x**2 * A.x + pi * A.y + x*y*z * A.z
+    assert v.xreplace({x*y*z : 1}) == x**2*A.x + x*y*A.y + A.z
+    assert v.xreplace({x:1, z:0}) == A.x + y * A.y
+    raises(TypeError, lambda: v.xreplace())
+    raises(TypeError, lambda: v.xreplace([x, y]))
+
+def test_issue_23366():
+    u1 = dynamicsymbols('u1')
+    N = ReferenceFrame('N')
+    N_v_A = u1*N.x
+    raises(VectorTypeError, lambda: N_v_A.diff(N, u1))
+
+
+def test_vector_outer():
+    a, b, c, d, e, f = symbols('a, b, c, d, e, f')
+    N = ReferenceFrame('N')
+    v1 = a*N.x + b*N.y + c*N.z
+    v2 = d*N.x + e*N.y + f*N.z
+    v1v2 = Matrix([[a*d, a*e, a*f],
+                   [b*d, b*e, b*f],
+                   [c*d, c*e, c*f]])
+    assert v1.outer(v2).to_matrix(N) == v1v2
+    assert (v1 | v2).to_matrix(N) == v1v2
+    v2v1 = Matrix([[d*a, d*b, d*c],
+                   [e*a, e*b, e*c],
+                   [f*a, f*b, f*c]])
+    assert v2.outer(v1).to_matrix(N) == v2v1
+    assert (v2 | v1).to_matrix(N) == v2v1
+
+
+def test_overloaded_operators():
+    a, b, c, d, e, f = symbols('a, b, c, d, e, f')
+    N = ReferenceFrame('N')
+    v1 = a*N.x + b*N.y + c*N.z
+    v2 = d*N.x + e*N.y + f*N.z
+
+    assert v1 + v2 == v2 + v1
+    assert v1 - v2 == -v2 + v1
+    assert v1 & v2 == v2 & v1
+    assert v1 ^ v2 == v1.cross(v2)
+    assert v2 ^ v1 == v2.cross(v1)

rl/Lib/site-packages/sympy/physics/vector/vector.py

@@ -0,0 +1,806 @@
+from sympy import (S, sympify, expand, sqrt, Add, zeros, acos,
+                   ImmutableMatrix as Matrix, simplify)
+from sympy.simplify.trigsimp import trigsimp
+from sympy.printing.defaults import Printable
+from sympy.utilities.misc import filldedent
+from sympy.core.evalf import EvalfMixin
+
+from mpmath.libmp.libmpf import prec_to_dps
+
+
+__all__ = ['Vector']
+
+
+class Vector(Printable, EvalfMixin):
+    """The class used to define vectors.
+
+    It along with ReferenceFrame are the building blocks of describing a
+    classical mechanics system in PyDy and sympy.physics.vector.
+
+    Attributes
+    ==========
+
+    simp : Boolean
+        Let certain methods use trigsimp on their outputs
+
+    """
+
+    simp = False
+    is_number = False
+
+    def __init__(self, inlist):
+        """This is the constructor for the Vector class. You should not be
+        calling this, it should only be used by other functions. You should be
+        treating Vectors like you would with if you were doing the math by
+        hand, and getting the first 3 from the standard basis vectors from a
+        ReferenceFrame.
+
+        The only exception is to create a zero vector:
+        zv = Vector(0)
+
+        """
+
+        self.args = []
+        if inlist == 0:
+            inlist = []
+        if isinstance(inlist, dict):
+            d = inlist
+        else:
+            d = {}
+            for inp in inlist:
+                if inp[1] in d:
+                    d[inp[1]] += inp[0]
+                else:
+                    d[inp[1]] = inp[0]
+
+        for k, v in d.items():
+            if v != Matrix([0, 0, 0]):
+                self.args.append((v, k))
+
+    @property
+    def func(self):
+        """Returns the class Vector. """
+        return Vector
+
+    def __hash__(self):
+        return hash(tuple(self.args))
+
+    def __add__(self, other):
+        """The add operator for Vector. """
+        if other == 0:
+            return self
+        other = _check_vector(other)
+        return Vector(self.args + other.args)
+
+    def dot(self, other):
+        """Dot product of two vectors.
+
+        Returns a scalar, the dot product of the two Vectors
+
+        Parameters
+        ==========
+
+        other : Vector
+            The Vector which we are dotting with
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, dot
+        >>> from sympy import symbols
+        >>> q1 = symbols('q1')
+        >>> N = ReferenceFrame('N')
+        >>> dot(N.x, N.x)
+        1
+        >>> dot(N.x, N.y)
+        0
+        >>> A = N.orientnew('A', 'Axis', [q1, N.x])
+        >>> dot(N.y, A.y)
+        cos(q1)
+
+        """
+
+        from sympy.physics.vector.dyadic import Dyadic, _check_dyadic
+        if isinstance(other, Dyadic):
+            other = _check_dyadic(other)
+            ol = Vector(0)
+            for v in other.args:
+                ol += v[0] * v[2] * (v[1].dot(self))
+            return ol
+        other = _check_vector(other)
+        out = S.Zero
+        for v1 in self.args:
+            for v2 in other.args:
+                out += ((v2[0].T) * (v2[1].dcm(v1[1])) * (v1[0]))[0]
+        if Vector.simp:
+            return trigsimp(out, recursive=True)
+        else:
+            return out
+
+    def __truediv__(self, other):
+        """This uses mul and inputs self and 1 divided by other. """
+        return self.__mul__(S.One / other)
+
+    def __eq__(self, other):
+        """Tests for equality.
+
+        It is very import to note that this is only as good as the SymPy
+        equality test; False does not always mean they are not equivalent
+        Vectors.
+        If other is 0, and self is empty, returns True.
+        If other is 0 and self is not empty, returns False.
+        If none of the above, only accepts other as a Vector.
+
+        """
+
+        if other == 0:
+            other = Vector(0)
+        try:
+            other = _check_vector(other)
+        except TypeError:
+            return False
+        if (self.args == []) and (other.args == []):
+            return True
+        elif (self.args == []) or (other.args == []):
+            return False
+
+        frame = self.args[0][1]
+        for v in frame:
+            if expand((self - other).dot(v)) != 0:
+                return False
+        return True
+
+    def __mul__(self, other):
+        """Multiplies the Vector by a sympifyable expression.
+
+        Parameters
+        ==========
+
+        other : Sympifyable
+            The scalar to multiply this Vector with
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> from sympy import Symbol
+        >>> N = ReferenceFrame('N')
+        >>> b = Symbol('b')
+        >>> V = 10 * b * N.x
+        >>> print(V)
+        10*b*N.x
+
+        """
+
+        newlist = list(self.args)
+        other = sympify(other)
+        for i, v in enumerate(newlist):
+            newlist[i] = (other * newlist[i][0], newlist[i][1])
+        return Vector(newlist)
+
+    def __neg__(self):
+        return self * -1
+
+    def outer(self, other):
+        """Outer product between two Vectors.
+
+        A rank increasing operation, which returns a Dyadic from two Vectors
+
+        Parameters
+        ==========
+
+        other : Vector
+            The Vector to take the outer product with
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, outer
+        >>> N = ReferenceFrame('N')
+        >>> outer(N.x, N.x)
+        (N.x|N.x)
+
+        """
+
+        from sympy.physics.vector.dyadic import Dyadic
+        other = _check_vector(other)
+        ol = Dyadic(0)
+        for v in self.args:
+            for v2 in other.args:
+                # it looks this way because if we are in the same frame and
+                # use the enumerate function on the same frame in a nested
+                # fashion, then bad things happen
+                ol += Dyadic([(v[0][0] * v2[0][0], v[1].x, v2[1].x)])
+                ol += Dyadic([(v[0][0] * v2[0][1], v[1].x, v2[1].y)])
+                ol += Dyadic([(v[0][0] * v2[0][2], v[1].x, v2[1].z)])
+                ol += Dyadic([(v[0][1] * v2[0][0], v[1].y, v2[1].x)])
+                ol += Dyadic([(v[0][1] * v2[0][1], v[1].y, v2[1].y)])
+                ol += Dyadic([(v[0][1] * v2[0][2], v[1].y, v2[1].z)])
+                ol += Dyadic([(v[0][2] * v2[0][0], v[1].z, v2[1].x)])
+                ol += Dyadic([(v[0][2] * v2[0][1], v[1].z, v2[1].y)])
+                ol += Dyadic([(v[0][2] * v2[0][2], v[1].z, v2[1].z)])
+        return ol
+
+    def _latex(self, printer):
+        """Latex Printing method. """
+
+        ar = self.args  # just to shorten things
+        if len(ar) == 0:
+            return str(0)
+        ol = []  # output list, to be concatenated to a string
+        for i, v in enumerate(ar):
+            for j in 0, 1, 2:
+                # if the coef of the basis vector is 1, we skip the 1
+                if ar[i][0][j] == 1:
+                    ol.append(' + ' + ar[i][1].latex_vecs[j])
+                # if the coef of the basis vector is -1, we skip the 1
+                elif ar[i][0][j] == -1:
+                    ol.append(' - ' + ar[i][1].latex_vecs[j])
+                elif ar[i][0][j] != 0:
+                    # If the coefficient of the basis vector is not 1 or -1;
+                    # also, we might wrap it in parentheses, for readability.
+                    arg_str = printer._print(ar[i][0][j])
+                    if isinstance(ar[i][0][j], Add):
+                        arg_str = "(%s)" % arg_str
+                    if arg_str[0] == '-':
+                        arg_str = arg_str[1:]
+                        str_start = ' - '
+                    else:
+                        str_start = ' + '
+                    ol.append(str_start + arg_str + ar[i][1].latex_vecs[j])
+        outstr = ''.join(ol)
+        if outstr.startswith(' + '):
+            outstr = outstr[3:]
+        elif outstr.startswith(' '):
+            outstr = outstr[1:]
+        return outstr
+
+    def _pretty(self, printer):
+        """Pretty Printing method. """
+        from sympy.printing.pretty.stringpict import prettyForm
+
+        terms = []
+
+        def juxtapose(a, b):
+            pa = printer._print(a)
+            pb = printer._print(b)
+            if a.is_Add:
+                pa = prettyForm(*pa.parens())
+            return printer._print_seq([pa, pb], delimiter=' ')
+
+        for M, N in self.args:
+            for i in range(3):
+                if M[i] == 0:
+                    continue
+                elif M[i] == 1:
+                    terms.append(prettyForm(N.pretty_vecs[i]))
+                elif M[i] == -1:
+                    terms.append(prettyForm("-1") * prettyForm(N.pretty_vecs[i]))
+                else:
+                    terms.append(juxtapose(M[i], N.pretty_vecs[i]))
+
+        if terms:
+            pretty_result = prettyForm.__add__(*terms)
+        else:
+            pretty_result = prettyForm("0")
+
+        return pretty_result
+
+    def __rsub__(self, other):
+        return (-1 * self) + other
+
+    def _sympystr(self, printer, order=True):
+        """Printing method. """
+        if not order or len(self.args) == 1:
+            ar = list(self.args)
+        elif len(self.args) == 0:
+            return printer._print(0)
+        else:
+            d = {v[1]: v[0] for v in self.args}
+            keys = sorted(d.keys(), key=lambda x: x.index)
+            ar = []
+            for key in keys:
+                ar.append((d[key], key))
+        ol = []  # output list, to be concatenated to a string
+        for i, v in enumerate(ar):
+            for j in 0, 1, 2:
+                # if the coef of the basis vector is 1, we skip the 1
+                if ar[i][0][j] == 1:
+                    ol.append(' + ' + ar[i][1].str_vecs[j])
+                # if the coef of the basis vector is -1, we skip the 1
+                elif ar[i][0][j] == -1:
+                    ol.append(' - ' + ar[i][1].str_vecs[j])
+                elif ar[i][0][j] != 0:
+                    # If the coefficient of the basis vector is not 1 or -1;
+                    # also, we might wrap it in parentheses, for readability.
+                    arg_str = printer._print(ar[i][0][j])
+                    if isinstance(ar[i][0][j], Add):
+                        arg_str = "(%s)" % arg_str
+                    if arg_str[0] == '-':
+                        arg_str = arg_str[1:]
+                        str_start = ' - '
+                    else:
+                        str_start = ' + '
+                    ol.append(str_start + arg_str + '*' + ar[i][1].str_vecs[j])
+        outstr = ''.join(ol)
+        if outstr.startswith(' + '):
+            outstr = outstr[3:]
+        elif outstr.startswith(' '):
+            outstr = outstr[1:]
+        return outstr
+
+    def __sub__(self, other):
+        """The subtraction operator. """
+        return self.__add__(other * -1)
+
+    def cross(self, other):
+        """The cross product operator for two Vectors.
+
+        Returns a Vector, expressed in the same ReferenceFrames as self.
+
+        Parameters
+        ==========
+
+        other : Vector
+            The Vector which we are crossing with
+
+        Examples
+        ========
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.vector import ReferenceFrame, cross
+        >>> q1 = symbols('q1')
+        >>> N = ReferenceFrame('N')
+        >>> cross(N.x, N.y)
+        N.z
+        >>> A = ReferenceFrame('A')
+        >>> A.orient_axis(N, q1, N.x)
+        >>> cross(A.x, N.y)
+        N.z
+        >>> cross(N.y, A.x)
+        - sin(q1)*A.y - cos(q1)*A.z
+
+        """
+
+        from sympy.physics.vector.dyadic import Dyadic, _check_dyadic
+        if isinstance(other, Dyadic):
+            other = _check_dyadic(other)
+            ol = Dyadic(0)
+            for i, v in enumerate(other.args):
+                ol += v[0] * ((self.cross(v[1])).outer(v[2]))
+            return ol
+        other = _check_vector(other)
+        if other.args == []:
+            return Vector(0)
+
+        def _det(mat):
+            """This is needed as a little method for to find the determinant
+            of a list in python; needs to work for a 3x3 list.
+            SymPy's Matrix will not take in Vector, so need a custom function.
+            You should not be calling this.
+
+            """
+
+            return (mat[0][0] * (mat[1][1] * mat[2][2] - mat[1][2] * mat[2][1])
+                    + mat[0][1] * (mat[1][2] * mat[2][0] - mat[1][0] *
+                    mat[2][2]) + mat[0][2] * (mat[1][0] * mat[2][1] -
+                    mat[1][1] * mat[2][0]))
+
+        outlist = []
+        ar = other.args  # For brevity
+        for i, v in enumerate(ar):
+            tempx = v[1].x
+            tempy = v[1].y
+            tempz = v[1].z
+            tempm = ([[tempx, tempy, tempz],
+                      [self.dot(tempx), self.dot(tempy), self.dot(tempz)],
+                      [Vector([ar[i]]).dot(tempx), Vector([ar[i]]).dot(tempy),
+                       Vector([ar[i]]).dot(tempz)]])
+            outlist += _det(tempm).args
+        return Vector(outlist)
+
+    __radd__ = __add__
+    __rmul__ = __mul__
+
+    def separate(self):
+        """
+        The constituents of this vector in different reference frames,
+        as per its definition.
+
+        Returns a dict mapping each ReferenceFrame to the corresponding
+        constituent Vector.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> R1 = ReferenceFrame('R1')
+        >>> R2 = ReferenceFrame('R2')
+        >>> v = R1.x + R2.x
+        >>> v.separate() == {R1: R1.x, R2: R2.x}
+        True
+
+        """
+
+        components = {}
+        for x in self.args:
+            components[x[1]] = Vector([x])
+        return components
+
+    def __and__(self, other):
+        return self.dot(other)
+    __and__.__doc__ = dot.__doc__
+    __rand__ = __and__
+
+    def __xor__(self, other):
+        return self.cross(other)
+    __xor__.__doc__ = cross.__doc__
+
+    def __or__(self, other):
+        return self.outer(other)
+    __or__.__doc__ = outer.__doc__
+
+    def diff(self, var, frame, var_in_dcm=True):
+        """Returns the partial derivative of the vector with respect to a
+        variable in the provided reference frame.
+
+        Parameters
+        ==========
+        var : Symbol
+            What the partial derivative is taken with respect to.
+        frame : ReferenceFrame
+            The reference frame that the partial derivative is taken in.
+        var_in_dcm : boolean
+            If true, the differentiation algorithm assumes that the variable
+            may be present in any of the direction cosine matrices that relate
+            the frame to the frames of any component of the vector. But if it
+            is known that the variable is not present in the direction cosine
+            matrices, false can be set to skip full reexpression in the desired
+            frame.
+
+        Examples
+        ========
+
+        >>> from sympy import Symbol
+        >>> from sympy.physics.vector import dynamicsymbols, ReferenceFrame
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> t = Symbol('t')
+        >>> q1 = dynamicsymbols('q1')
+        >>> N = ReferenceFrame('N')
+        >>> A = N.orientnew('A', 'Axis', [q1, N.y])
+        >>> A.x.diff(t, N)
+        - sin(q1)*q1'*N.x - cos(q1)*q1'*N.z
+        >>> A.x.diff(t, N).express(A).simplify()
+        - q1'*A.z
+        >>> B = ReferenceFrame('B')
+        >>> u1, u2 = dynamicsymbols('u1, u2')
+        >>> v = u1 * A.x + u2 * B.y
+        >>> v.diff(u2, N, var_in_dcm=False)
+        B.y
+
+        """
+
+        from sympy.physics.vector.frame import _check_frame
+
+        _check_frame(frame)
+        var = sympify(var)
+
+        inlist = []
+
+        for vector_component in self.args:
+            measure_number = vector_component[0]
+            component_frame = vector_component[1]
+            if component_frame == frame:
+                inlist += [(measure_number.diff(var), frame)]
+            else:
+                # If the direction cosine matrix relating the component frame
+                # with the derivative frame does not contain the variable.
+                if not var_in_dcm or (frame.dcm(component_frame).diff(var) ==
+                                      zeros(3, 3)):
+                    inlist += [(measure_number.diff(var), component_frame)]
+                else:  # else express in the frame
+                    reexp_vec_comp = Vector([vector_component]).express(frame)
+                    deriv = reexp_vec_comp.args[0][0].diff(var)
+                    inlist += Vector([(deriv, frame)]).args
+
+        return Vector(inlist)
+
+    def express(self, otherframe, variables=False):
+        """
+        Returns a Vector equivalent to this one, expressed in otherframe.
+        Uses the global express method.
+
+        Parameters
+        ==========
+
+        otherframe : ReferenceFrame
+            The frame for this Vector to be described in
+
+        variables : boolean
+            If True, the coordinate symbols(if present) in this Vector
+            are re-expressed in terms otherframe
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
+        >>> from sympy.physics.vector import init_vprinting
+        >>> init_vprinting(pretty_print=False)
+        >>> q1 = dynamicsymbols('q1')
+        >>> N = ReferenceFrame('N')
+        >>> A = N.orientnew('A', 'Axis', [q1, N.y])
+        >>> A.x.express(N)
+        cos(q1)*N.x - sin(q1)*N.z
+
+        """
+        from sympy.physics.vector import express
+        return express(self, otherframe, variables=variables)
+
+    def to_matrix(self, reference_frame):
+        """Returns the matrix form of the vector with respect to the given
+        frame.
+
+        Parameters
+        ----------
+        reference_frame : ReferenceFrame
+            The reference frame that the rows of the matrix correspond to.
+
+        Returns
+        -------
+        matrix : ImmutableMatrix, shape(3,1)
+            The matrix that gives the 1D vector.
+
+        Examples
+        ========
+
+        >>> from sympy import symbols
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> a, b, c = symbols('a, b, c')
+        >>> N = ReferenceFrame('N')
+        >>> vector = a * N.x + b * N.y + c * N.z
+        >>> vector.to_matrix(N)
+        Matrix([
+        [a],
+        [b],
+        [c]])
+        >>> beta = symbols('beta')
+        >>> A = N.orientnew('A', 'Axis', (beta, N.x))
+        >>> vector.to_matrix(A)
+        Matrix([
+        [                         a],
+        [ b*cos(beta) + c*sin(beta)],
+        [-b*sin(beta) + c*cos(beta)]])
+
+        """
+
+        return Matrix([self.dot(unit_vec) for unit_vec in
+                       reference_frame]).reshape(3, 1)
+
+    def doit(self, **hints):
+        """Calls .doit() on each term in the Vector"""
+        d = {}
+        for v in self.args:
+            d[v[1]] = v[0].applyfunc(lambda x: x.doit(**hints))
+        return Vector(d)
+
+    def dt(self, otherframe):
+        """
+        Returns a Vector which is the time derivative of
+        the self Vector, taken in frame otherframe.
+
+        Calls the global time_derivative method
+
+        Parameters
+        ==========
+
+        otherframe : ReferenceFrame
+            The frame to calculate the time derivative in
+
+        """
+        from sympy.physics.vector import time_derivative
+        return time_derivative(self, otherframe)
+
+    def simplify(self):
+        """Returns a simplified Vector."""
+        d = {}
+        for v in self.args:
+            d[v[1]] = simplify(v[0])
+        return Vector(d)
+
+    def subs(self, *args, **kwargs):
+        """Substitution on the Vector.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> from sympy import Symbol
+        >>> N = ReferenceFrame('N')
+        >>> s = Symbol('s')
+        >>> a = N.x * s
+        >>> a.subs({s: 2})
+        2*N.x
+
+        """
+
+        d = {}
+        for v in self.args:
+            d[v[1]] = v[0].subs(*args, **kwargs)
+        return Vector(d)
+
+    def magnitude(self):
+        """Returns the magnitude (Euclidean norm) of self.
+
+        Warnings
+        ========
+
+        Python ignores the leading negative sign so that might
+        give wrong results.
+        ``-A.x.magnitude()`` would be treated as ``-(A.x.magnitude())``,
+        instead of ``(-A.x).magnitude()``.
+
+        """
+        return sqrt(self.dot(self))
+
+    def normalize(self):
+        """Returns a Vector of magnitude 1, codirectional with self."""
+        return Vector(self.args + []) / self.magnitude()
+
+    def applyfunc(self, f):
+        """Apply a function to each component of a vector."""
+        if not callable(f):
+            raise TypeError("`f` must be callable.")
+
+        d = {}
+        for v in self.args:
+            d[v[1]] = v[0].applyfunc(f)
+        return Vector(d)
+
+    def angle_between(self, vec):
+        """
+        Returns the smallest angle between Vector 'vec' and self.
+
+        Parameter
+        =========
+
+        vec : Vector
+            The Vector between which angle is needed.
+
+        Examples
+        ========
+
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> A = ReferenceFrame("A")
+        >>> v1 = A.x
+        >>> v2 = A.y
+        >>> v1.angle_between(v2)
+        pi/2
+
+        >>> v3 = A.x + A.y + A.z
+        >>> v1.angle_between(v3)
+        acos(sqrt(3)/3)
+
+        Warnings
+        ========
+
+        Python ignores the leading negative sign so that might give wrong
+        results. ``-A.x.angle_between()`` would be treated as
+        ``-(A.x.angle_between())``, instead of ``(-A.x).angle_between()``.
+
+        """
+
+        vec1 = self.normalize()
+        vec2 = vec.normalize()
+        angle = acos(vec1.dot(vec2))
+        return angle
+
+    def free_symbols(self, reference_frame):
+        """Returns the free symbols in the measure numbers of the vector
+        expressed in the given reference frame.
+
+        Parameters
+        ==========
+        reference_frame : ReferenceFrame
+            The frame with respect to which the free symbols of the given
+            vector is to be determined.
+
+        Returns
+        =======
+        set of Symbol
+            set of symbols present in the measure numbers of
+            ``reference_frame``.
+
+        """
+
+        return self.to_matrix(reference_frame).free_symbols
+
+    def free_dynamicsymbols(self, reference_frame):
+        """Returns the free dynamic symbols (functions of time ``t``) in the
+        measure numbers of the vector expressed in the given reference frame.
+
+        Parameters
+        ==========
+        reference_frame : ReferenceFrame
+            The frame with respect to which the free dynamic symbols of the
+            given vector is to be determined.
+
+        Returns
+        =======
+        set
+            Set of functions of time ``t``, e.g.
+            ``Function('f')(me.dynamicsymbols._t)``.
+
+        """
+        # TODO : Circular dependency if imported at top. Should move
+        # find_dynamicsymbols into physics.vector.functions.
+        from sympy.physics.mechanics.functions import find_dynamicsymbols
+
+        return find_dynamicsymbols(self, reference_frame=reference_frame)
+
+    def _eval_evalf(self, prec):
+        if not self.args:
+            return self
+        new_args = []
+        dps = prec_to_dps(prec)
+        for mat, frame in self.args:
+            new_args.append([mat.evalf(n=dps), frame])
+        return Vector(new_args)
+
+    def xreplace(self, rule):
+        """Replace occurrences of objects within the measure numbers of the
+        vector.
+
+        Parameters
+        ==========
+
+        rule : dict-like
+            Expresses a replacement rule.
+
+        Returns
+        =======
+
+        Vector
+            Result of the replacement.
+
+        Examples
+        ========
+
+        >>> from sympy import symbols, pi
+        >>> from sympy.physics.vector import ReferenceFrame
+        >>> A = ReferenceFrame('A')
+        >>> x, y, z = symbols('x y z')
+        >>> ((1 + x*y) * A.x).xreplace({x: pi})
+        (pi*y + 1)*A.x
+        >>> ((1 + x*y) * A.x).xreplace({x: pi, y: 2})
+        (1 + 2*pi)*A.x
+
+        Replacements occur only if an entire node in the expression tree is
+        matched:
+
+        >>> ((x*y + z) * A.x).xreplace({x*y: pi})
+        (z + pi)*A.x
+        >>> ((x*y*z) * A.x).xreplace({x*y: pi})
+        x*y*z*A.x
+
+        """
+
+        new_args = []
+        for mat, frame in self.args:
+            mat = mat.xreplace(rule)
+            new_args.append([mat, frame])
+        return Vector(new_args)
+
+
+class VectorTypeError(TypeError):
+
+    def __init__(self, other, want):
+        msg = filldedent("Expected an instance of %s, but received object "
+                         "'%s' of %s." % (type(want), other, type(other)))
+        super().__init__(msg)
+
+
+def _check_vector(other):
+    if not isinstance(other, Vector):
+        raise TypeError('A Vector must be supplied')
+    return other