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rl/Lib/site-packages/sympy/plotting/intervalmath/__init__.py

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+from .interval_arithmetic import interval
+from .lib_interval import (Abs, exp, log, log10, sin, cos, tan, sqrt,
+                          imin, imax, sinh, cosh, tanh, acosh, asinh, atanh,
+                          asin, acos, atan, ceil, floor, And, Or)
+
+__all__ = [
+    'interval',
+
+    'Abs', 'exp', 'log', 'log10', 'sin', 'cos', 'tan', 'sqrt', 'imin', 'imax',
+    'sinh', 'cosh', 'tanh', 'acosh', 'asinh', 'atanh', 'asin', 'acos', 'atan',
+    'ceil', 'floor', 'And', 'Or',
+]

rl/Lib/site-packages/sympy/plotting/intervalmath/interval_arithmetic.py

@@ -0,0 +1,413 @@
+"""
+Interval Arithmetic for plotting.
+This module does not implement interval arithmetic accurately and
+hence cannot be used for purposes other than plotting. If you want
+to use interval arithmetic, use mpmath's interval arithmetic.
+
+The module implements interval arithmetic using numpy and
+python floating points. The rounding up and down is not handled
+and hence this is not an accurate implementation of interval
+arithmetic.
+
+The module uses numpy for speed which cannot be achieved with mpmath.
+"""
+
+# Q: Why use numpy? Why not simply use mpmath's interval arithmetic?
+# A: mpmath's interval arithmetic simulates a floating point unit
+# and hence is slow, while numpy evaluations are orders of magnitude
+# faster.
+
+# Q: Why create a separate class for intervals? Why not use SymPy's
+# Interval Sets?
+# A: The functionalities that will be required for plotting is quite
+# different from what Interval Sets implement.
+
+# Q: Why is rounding up and down according to IEEE754 not handled?
+# A: It is not possible to do it in both numpy and python. An external
+# library has to used, which defeats the whole purpose i.e., speed. Also
+# rounding is handled for very few functions in those libraries.
+
+# Q Will my plots be affected?
+# A It will not affect most of the plots. The interval arithmetic
+# module based suffers the same problems as that of floating point
+# arithmetic.
+
+from sympy.core.numbers import int_valued
+from sympy.core.logic import fuzzy_and
+from sympy.simplify.simplify import nsimplify
+
+from .interval_membership import intervalMembership
+
+
+class interval:
+    """ Represents an interval containing floating points as start and
+    end of the interval
+    The is_valid variable tracks whether the interval obtained as the
+    result of the function is in the domain and is continuous.
+    - True: Represents the interval result of a function is continuous and
+            in the domain of the function.
+    - False: The interval argument of the function was not in the domain of
+             the function, hence the is_valid of the result interval is False
+    - None: The function was not continuous over the interval or
+            the function's argument interval is partly in the domain of the
+            function
+
+    A comparison between an interval and a real number, or a
+    comparison between two intervals may return ``intervalMembership``
+    of two 3-valued logic values.
+    """
+
+    def __init__(self, *args, is_valid=True, **kwargs):
+        self.is_valid = is_valid
+        if len(args) == 1:
+            if isinstance(args[0], interval):
+                self.start, self.end = args[0].start, args[0].end
+            else:
+                self.start = float(args[0])
+                self.end = float(args[0])
+        elif len(args) == 2:
+            if args[0] < args[1]:
+                self.start = float(args[0])
+                self.end = float(args[1])
+            else:
+                self.start = float(args[1])
+                self.end = float(args[0])
+
+        else:
+            raise ValueError("interval takes a maximum of two float values "
+                            "as arguments")
+
+    @property
+    def mid(self):
+        return (self.start + self.end) / 2.0
+
+    @property
+    def width(self):
+        return self.end - self.start
+
+    def __repr__(self):
+        return "interval(%f, %f)" % (self.start, self.end)
+
+    def __str__(self):
+        return "[%f, %f]" % (self.start, self.end)
+
+    def __lt__(self, other):
+        if isinstance(other, (int, float)):
+            if self.end < other:
+                return intervalMembership(True, self.is_valid)
+            elif self.start > other:
+                return intervalMembership(False, self.is_valid)
+            else:
+                return intervalMembership(None, self.is_valid)
+
+        elif isinstance(other, interval):
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            if self.end < other. start:
+                return intervalMembership(True, valid)
+            if self.start > other.end:
+                return intervalMembership(False, valid)
+            return intervalMembership(None, valid)
+        else:
+            return NotImplemented
+
+    def __gt__(self, other):
+        if isinstance(other, (int, float)):
+            if self.start > other:
+                return intervalMembership(True, self.is_valid)
+            elif self.end < other:
+                return intervalMembership(False, self.is_valid)
+            else:
+                return intervalMembership(None, self.is_valid)
+        elif isinstance(other, interval):
+            return other.__lt__(self)
+        else:
+            return NotImplemented
+
+    def __eq__(self, other):
+        if isinstance(other, (int, float)):
+            if self.start == other and self.end == other:
+                return intervalMembership(True, self.is_valid)
+            if other in self:
+                return intervalMembership(None, self.is_valid)
+            else:
+                return intervalMembership(False, self.is_valid)
+
+        if isinstance(other, interval):
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            if self.start == other.start and self.end == other.end:
+                return intervalMembership(True, valid)
+            elif self.__lt__(other)[0] is not None:
+                return intervalMembership(False, valid)
+            else:
+                return intervalMembership(None, valid)
+        else:
+            return NotImplemented
+
+    def __ne__(self, other):
+        if isinstance(other, (int, float)):
+            if self.start == other and self.end == other:
+                return intervalMembership(False, self.is_valid)
+            if other in self:
+                return intervalMembership(None, self.is_valid)
+            else:
+                return intervalMembership(True, self.is_valid)
+
+        if isinstance(other, interval):
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            if self.start == other.start and self.end == other.end:
+                return intervalMembership(False, valid)
+            if not self.__lt__(other)[0] is None:
+                return intervalMembership(True, valid)
+            return intervalMembership(None, valid)
+        else:
+            return NotImplemented
+
+    def __le__(self, other):
+        if isinstance(other, (int, float)):
+            if self.end <= other:
+                return intervalMembership(True, self.is_valid)
+            if self.start > other:
+                return intervalMembership(False, self.is_valid)
+            else:
+                return intervalMembership(None, self.is_valid)
+
+        if isinstance(other, interval):
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            if self.end <= other.start:
+                return intervalMembership(True, valid)
+            if self.start > other.end:
+                return intervalMembership(False, valid)
+            return intervalMembership(None, valid)
+        else:
+            return NotImplemented
+
+    def __ge__(self, other):
+        if isinstance(other, (int, float)):
+            if self.start >= other:
+                return intervalMembership(True, self.is_valid)
+            elif self.end < other:
+                return intervalMembership(False, self.is_valid)
+            else:
+                return intervalMembership(None, self.is_valid)
+        elif isinstance(other, interval):
+            return other.__le__(self)
+
+    def __add__(self, other):
+        if isinstance(other, (int, float)):
+            if self.is_valid:
+                return interval(self.start + other, self.end + other)
+            else:
+                start = self.start + other
+                end = self.end + other
+                return interval(start, end, is_valid=self.is_valid)
+
+        elif isinstance(other, interval):
+            start = self.start + other.start
+            end = self.end + other.end
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            return interval(start, end, is_valid=valid)
+        else:
+            return NotImplemented
+
+    __radd__ = __add__
+
+    def __sub__(self, other):
+        if isinstance(other, (int, float)):
+            start = self.start - other
+            end = self.end - other
+            return interval(start, end, is_valid=self.is_valid)
+
+        elif isinstance(other, interval):
+            start = self.start - other.end
+            end = self.end - other.start
+            valid = fuzzy_and([self.is_valid, other.is_valid])
+            return interval(start, end, is_valid=valid)
+        else:
+            return NotImplemented
+
+    def __rsub__(self, other):
+        if isinstance(other, (int, float)):
+            start = other - self.end
+            end = other - self.start
+            return interval(start, end, is_valid=self.is_valid)
+        elif isinstance(other, interval):
+            return other.__sub__(self)
+        else:
+            return NotImplemented
+
+    def __neg__(self):
+        if self.is_valid:
+            return interval(-self.end, -self.start)
+        else:
+            return interval(-self.end, -self.start, is_valid=self.is_valid)
+
+    def __mul__(self, other):
+        if isinstance(other, interval):
+            if self.is_valid is False or other.is_valid is False:
+                return interval(-float('inf'), float('inf'), is_valid=False)
+            elif self.is_valid is None or other.is_valid is None:
+                return interval(-float('inf'), float('inf'), is_valid=None)
+            else:
+                inters = []
+                inters.append(self.start * other.start)
+                inters.append(self.end * other.start)
+                inters.append(self.start * other.end)
+                inters.append(self.end * other.end)
+                start = min(inters)
+                end = max(inters)
+                return interval(start, end)
+        elif isinstance(other, (int, float)):
+            return interval(self.start*other, self.end*other, is_valid=self.is_valid)
+        else:
+            return NotImplemented
+
+    __rmul__ = __mul__
+
+    def __contains__(self, other):
+        if isinstance(other, (int, float)):
+            return self.start <= other and self.end >= other
+        else:
+            return self.start <= other.start and other.end <= self.end
+
+    def __rtruediv__(self, other):
+        if isinstance(other, (int, float)):
+            other = interval(other)
+            return other.__truediv__(self)
+        elif isinstance(other, interval):
+            return other.__truediv__(self)
+        else:
+            return NotImplemented
+
+    def __truediv__(self, other):
+        # Both None and False are handled
+        if not self.is_valid:
+            # Don't divide as the value is not valid
+            return interval(-float('inf'), float('inf'), is_valid=self.is_valid)
+        if isinstance(other, (int, float)):
+            if other == 0:
+                # Divide by zero encountered. valid nowhere
+                return interval(-float('inf'), float('inf'), is_valid=False)
+            else:
+                return interval(self.start / other, self.end / other)
+
+        elif isinstance(other, interval):
+            if other.is_valid is False or self.is_valid is False:
+                return interval(-float('inf'), float('inf'), is_valid=False)
+            elif other.is_valid is None or self.is_valid is None:
+                return interval(-float('inf'), float('inf'), is_valid=None)
+            else:
+               # denominator contains both signs, i.e. being divided by zero
+               # return the whole real line with is_valid = None
+                if 0 in other:
+                    return interval(-float('inf'), float('inf'), is_valid=None)
+
+                # denominator negative
+                this = self
+                if other.end < 0:
+                    this = -this
+                    other = -other
+
+                # denominator positive
+                inters = []
+                inters.append(this.start / other.start)
+                inters.append(this.end / other.start)
+                inters.append(this.start / other.end)
+                inters.append(this.end / other.end)
+                start = max(inters)
+                end = min(inters)
+                return interval(start, end)
+        else:
+            return NotImplemented
+
+    def __pow__(self, other):
+        # Implements only power to an integer.
+        from .lib_interval import exp, log
+        if not self.is_valid:
+            return self
+        if isinstance(other, interval):
+            return exp(other * log(self))
+        elif isinstance(other, (float, int)):
+            if other < 0:
+                return 1 / self.__pow__(abs(other))
+            else:
+                if int_valued(other):
+                    return _pow_int(self, other)
+                else:
+                    return _pow_float(self, other)
+        else:
+            return NotImplemented
+
+    def __rpow__(self, other):
+        if isinstance(other, (float, int)):
+            if not self.is_valid:
+                #Don't do anything
+                return self
+            elif other < 0:
+                if self.width > 0:
+                    return interval(-float('inf'), float('inf'), is_valid=False)
+                else:
+                    power_rational = nsimplify(self.start)
+                    num, denom = power_rational.as_numer_denom()
+                    if denom % 2 == 0:
+                        return interval(-float('inf'), float('inf'),
+                                        is_valid=False)
+                    else:
+                        start = -abs(other)**self.start
+                        end = start
+                        return interval(start, end)
+            else:
+                return interval(other**self.start, other**self.end)
+        elif isinstance(other, interval):
+            return other.__pow__(self)
+        else:
+            return NotImplemented
+
+    def __hash__(self):
+        return hash((self.is_valid, self.start, self.end))
+
+
+def _pow_float(inter, power):
+    """Evaluates an interval raised to a floating point."""
+    power_rational = nsimplify(power)
+    num, denom = power_rational.as_numer_denom()
+    if num % 2 == 0:
+        start = abs(inter.start)**power
+        end = abs(inter.end)**power
+        if start < 0:
+            ret = interval(0, max(start, end))
+        else:
+            ret = interval(start, end)
+        return ret
+    elif denom % 2 == 0:
+        if inter.end < 0:
+            return interval(-float('inf'), float('inf'), is_valid=False)
+        elif inter.start < 0:
+            return interval(0, inter.end**power, is_valid=None)
+        else:
+            return interval(inter.start**power, inter.end**power)
+    else:
+        if inter.start < 0:
+            start = -abs(inter.start)**power
+        else:
+            start = inter.start**power
+
+        if inter.end < 0:
+            end = -abs(inter.end)**power
+        else:
+            end = inter.end**power
+
+        return interval(start, end, is_valid=inter.is_valid)
+
+
+def _pow_int(inter, power):
+    """Evaluates an interval raised to an integer power"""
+    power = int(power)
+    if power & 1:
+        return interval(inter.start**power, inter.end**power)
+    else:
+        if inter.start < 0 and inter.end > 0:
+            start = 0
+            end = max(inter.start**power, inter.end**power)
+            return interval(start, end)
+        else:
+            return interval(inter.start**power, inter.end**power)

rl/Lib/site-packages/sympy/plotting/intervalmath/interval_membership.py

@@ -0,0 +1,78 @@
+from sympy.core.logic import fuzzy_and, fuzzy_or, fuzzy_not, fuzzy_xor
+
+
+class intervalMembership:
+    """Represents a boolean expression returned by the comparison of
+    the interval object.
+
+    Parameters
+    ==========
+
+    (a, b) : (bool, bool)
+        The first value determines the comparison as follows:
+        - True: If the comparison is True throughout the intervals.
+        - False: If the comparison is False throughout the intervals.
+        - None: If the comparison is True for some part of the intervals.
+
+        The second value is determined as follows:
+        - True: If both the intervals in comparison are valid.
+        - False: If at least one of the intervals is False, else
+        - None
+    """
+    def __init__(self, a, b):
+        self._wrapped = (a, b)
+
+    def __getitem__(self, i):
+        try:
+            return self._wrapped[i]
+        except IndexError:
+            raise IndexError(
+                "{} must be a valid indexing for the 2-tuple."
+                .format(i))
+
+    def __len__(self):
+        return 2
+
+    def __iter__(self):
+        return iter(self._wrapped)
+
+    def __str__(self):
+        return "intervalMembership({}, {})".format(*self)
+    __repr__ = __str__
+
+    def __and__(self, other):
+        if not isinstance(other, intervalMembership):
+            raise ValueError(
+                "The comparison is not supported for {}.".format(other))
+
+        a1, b1 = self
+        a2, b2 = other
+        return intervalMembership(fuzzy_and([a1, a2]), fuzzy_and([b1, b2]))
+
+    def __or__(self, other):
+        if not isinstance(other, intervalMembership):
+            raise ValueError(
+                "The comparison is not supported for {}.".format(other))
+
+        a1, b1 = self
+        a2, b2 = other
+        return intervalMembership(fuzzy_or([a1, a2]), fuzzy_and([b1, b2]))
+
+    def __invert__(self):
+        a, b = self
+        return intervalMembership(fuzzy_not(a), b)
+
+    def __xor__(self, other):
+        if not isinstance(other, intervalMembership):
+            raise ValueError(
+                "The comparison is not supported for {}.".format(other))
+
+        a1, b1 = self
+        a2, b2 = other
+        return intervalMembership(fuzzy_xor([a1, a2]), fuzzy_and([b1, b2]))
+
+    def __eq__(self, other):
+        return self._wrapped == other
+
+    def __ne__(self, other):
+        return self._wrapped != other

rl/Lib/site-packages/sympy/plotting/intervalmath/lib_interval.py

@@ -0,0 +1,452 @@
+""" The module contains implemented functions for interval arithmetic."""
+from functools import reduce
+
+from sympy.plotting.intervalmath import interval
+from sympy.external import import_module
+
+
+def Abs(x):
+    if isinstance(x, (int, float)):
+        return interval(abs(x))
+    elif isinstance(x, interval):
+        if x.start < 0 and x.end > 0:
+            return interval(0, max(abs(x.start), abs(x.end)), is_valid=x.is_valid)
+        else:
+            return interval(abs(x.start), abs(x.end))
+    else:
+        raise NotImplementedError
+
+#Monotonic
+
+
+def exp(x):
+    """evaluates the exponential of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.exp(x), np.exp(x))
+    elif isinstance(x, interval):
+        return interval(np.exp(x.start), np.exp(x.end), is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+#Monotonic
+def log(x):
+    """evaluates the natural logarithm of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        if x <= 0:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.log(x))
+    elif isinstance(x, interval):
+        if not x.is_valid:
+            return interval(-np.inf, np.inf, is_valid=x.is_valid)
+        elif x.end <= 0:
+            return interval(-np.inf, np.inf, is_valid=False)
+        elif x.start <= 0:
+            return interval(-np.inf, np.inf, is_valid=None)
+
+        return interval(np.log(x.start), np.log(x.end))
+    else:
+        raise NotImplementedError
+
+
+#Monotonic
+def log10(x):
+    """evaluates the logarithm to the base 10 of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        if x <= 0:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.log10(x))
+    elif isinstance(x, interval):
+        if not x.is_valid:
+            return interval(-np.inf, np.inf, is_valid=x.is_valid)
+        elif x.end <= 0:
+            return interval(-np.inf, np.inf, is_valid=False)
+        elif x.start <= 0:
+            return interval(-np.inf, np.inf, is_valid=None)
+        return interval(np.log10(x.start), np.log10(x.end))
+    else:
+        raise NotImplementedError
+
+
+#Monotonic
+def atan(x):
+    """evaluates the tan inverse of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.arctan(x))
+    elif isinstance(x, interval):
+        start = np.arctan(x.start)
+        end = np.arctan(x.end)
+        return interval(start, end, is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+#periodic
+def sin(x):
+    """evaluates the sine of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.sin(x))
+    elif isinstance(x, interval):
+        if not x.is_valid:
+            return interval(-1, 1, is_valid=x.is_valid)
+        na, __ = divmod(x.start, np.pi / 2.0)
+        nb, __ = divmod(x.end, np.pi / 2.0)
+        start = min(np.sin(x.start), np.sin(x.end))
+        end = max(np.sin(x.start), np.sin(x.end))
+        if nb - na > 4:
+            return interval(-1, 1, is_valid=x.is_valid)
+        elif na == nb:
+            return interval(start, end, is_valid=x.is_valid)
+        else:
+            if (na - 1) // 4 != (nb - 1) // 4:
+                #sin has max
+                end = 1
+            if (na - 3) // 4 != (nb - 3) // 4:
+                #sin has min
+                start = -1
+            return interval(start, end)
+    else:
+        raise NotImplementedError
+
+
+#periodic
+def cos(x):
+    """Evaluates the cos of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.sin(x))
+    elif isinstance(x, interval):
+        if not (np.isfinite(x.start) and np.isfinite(x.end)):
+            return interval(-1, 1, is_valid=x.is_valid)
+        na, __ = divmod(x.start, np.pi / 2.0)
+        nb, __ = divmod(x.end, np.pi / 2.0)
+        start = min(np.cos(x.start), np.cos(x.end))
+        end = max(np.cos(x.start), np.cos(x.end))
+        if nb - na > 4:
+            #differ more than 2*pi
+            return interval(-1, 1, is_valid=x.is_valid)
+        elif na == nb:
+            #in the same quadarant
+            return interval(start, end, is_valid=x.is_valid)
+        else:
+            if (na) // 4 != (nb) // 4:
+                #cos has max
+                end = 1
+            if (na - 2) // 4 != (nb - 2) // 4:
+                #cos has min
+                start = -1
+            return interval(start, end, is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+def tan(x):
+    """Evaluates the tan of an interval"""
+    return sin(x) / cos(x)
+
+
+#Monotonic
+def sqrt(x):
+    """Evaluates the square root of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        if x > 0:
+            return interval(np.sqrt(x))
+        else:
+            return interval(-np.inf, np.inf, is_valid=False)
+    elif isinstance(x, interval):
+        #Outside the domain
+        if x.end < 0:
+            return interval(-np.inf, np.inf, is_valid=False)
+        #Partially outside the domain
+        elif x.start < 0:
+            return interval(-np.inf, np.inf, is_valid=None)
+        else:
+            return interval(np.sqrt(x.start), np.sqrt(x.end),
+                    is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+def imin(*args):
+    """Evaluates the minimum of a list of intervals"""
+    np = import_module('numpy')
+    if not all(isinstance(arg, (int, float, interval)) for arg in args):
+        return NotImplementedError
+    else:
+        new_args = [a for a in args if isinstance(a, (int, float))
+                    or a.is_valid]
+        if len(new_args) == 0:
+            if all(a.is_valid is False for a in args):
+                return interval(-np.inf, np.inf, is_valid=False)
+            else:
+                return interval(-np.inf, np.inf, is_valid=None)
+        start_array = [a if isinstance(a, (int, float)) else a.start
+                       for a in new_args]
+
+        end_array = [a if isinstance(a, (int, float)) else a.end
+                     for a in new_args]
+        return interval(min(start_array), min(end_array))
+
+
+def imax(*args):
+    """Evaluates the maximum of a list of intervals"""
+    np = import_module('numpy')
+    if not all(isinstance(arg, (int, float, interval)) for arg in args):
+        return NotImplementedError
+    else:
+        new_args = [a for a in args if isinstance(a, (int, float))
+                    or a.is_valid]
+        if len(new_args) == 0:
+            if all(a.is_valid is False for a in args):
+                return interval(-np.inf, np.inf, is_valid=False)
+            else:
+                return interval(-np.inf, np.inf, is_valid=None)
+        start_array = [a if isinstance(a, (int, float)) else a.start
+                       for a in new_args]
+
+        end_array = [a if isinstance(a, (int, float)) else a.end
+                     for a in new_args]
+
+        return interval(max(start_array), max(end_array))
+
+
+#Monotonic
+def sinh(x):
+    """Evaluates the hyperbolic sine of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.sinh(x), np.sinh(x))
+    elif isinstance(x, interval):
+        return interval(np.sinh(x.start), np.sinh(x.end), is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+def cosh(x):
+    """Evaluates the hyperbolic cos of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.cosh(x), np.cosh(x))
+    elif isinstance(x, interval):
+        #both signs
+        if x.start < 0 and x.end > 0:
+            end = max(np.cosh(x.start), np.cosh(x.end))
+            return interval(1, end, is_valid=x.is_valid)
+        else:
+            #Monotonic
+            start = np.cosh(x.start)
+            end = np.cosh(x.end)
+            return interval(start, end, is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+#Monotonic
+def tanh(x):
+    """Evaluates the hyperbolic tan of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.tanh(x), np.tanh(x))
+    elif isinstance(x, interval):
+        return interval(np.tanh(x.start), np.tanh(x.end), is_valid=x.is_valid)
+    else:
+        raise NotImplementedError
+
+
+def asin(x):
+    """Evaluates the inverse sine of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        #Outside the domain
+        if abs(x) > 1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.arcsin(x), np.arcsin(x))
+    elif isinstance(x, interval):
+        #Outside the domain
+        if x.is_valid is False or x.start > 1 or x.end < -1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        #Partially outside the domain
+        elif x.start < -1 or x.end > 1:
+            return interval(-np.inf, np.inf, is_valid=None)
+        else:
+            start = np.arcsin(x.start)
+            end = np.arcsin(x.end)
+            return interval(start, end, is_valid=x.is_valid)
+
+
+def acos(x):
+    """Evaluates the inverse cos of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        if abs(x) > 1:
+            #Outside the domain
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.arccos(x), np.arccos(x))
+    elif isinstance(x, interval):
+        #Outside the domain
+        if x.is_valid is False or x.start > 1 or x.end < -1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        #Partially outside the domain
+        elif x.start < -1 or x.end > 1:
+            return interval(-np.inf, np.inf, is_valid=None)
+        else:
+            start = np.arccos(x.start)
+            end = np.arccos(x.end)
+            return interval(start, end, is_valid=x.is_valid)
+
+
+def ceil(x):
+    """Evaluates the ceiling of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.ceil(x))
+    elif isinstance(x, interval):
+        if x.is_valid is False:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            start = np.ceil(x.start)
+            end = np.ceil(x.end)
+            #Continuous over the interval
+            if start == end:
+                return interval(start, end, is_valid=x.is_valid)
+            else:
+                #Not continuous over the interval
+                return interval(start, end, is_valid=None)
+    else:
+        return NotImplementedError
+
+
+def floor(x):
+    """Evaluates the floor of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.floor(x))
+    elif isinstance(x, interval):
+        if x.is_valid is False:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            start = np.floor(x.start)
+            end = np.floor(x.end)
+            #continuous over the argument
+            if start == end:
+                return interval(start, end, is_valid=x.is_valid)
+            else:
+                #not continuous over the interval
+                return interval(start, end, is_valid=None)
+    else:
+        return NotImplementedError
+
+
+def acosh(x):
+    """Evaluates the inverse hyperbolic cosine of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        #Outside the domain
+        if x < 1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.arccosh(x))
+    elif isinstance(x, interval):
+        #Outside the domain
+        if x.end < 1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        #Partly outside the domain
+        elif x.start < 1:
+            return interval(-np.inf, np.inf, is_valid=None)
+        else:
+            start = np.arccosh(x.start)
+            end = np.arccosh(x.end)
+            return interval(start, end, is_valid=x.is_valid)
+    else:
+        return NotImplementedError
+
+
+#Monotonic
+def asinh(x):
+    """Evaluates the inverse hyperbolic sine of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        return interval(np.arcsinh(x))
+    elif isinstance(x, interval):
+        start = np.arcsinh(x.start)
+        end = np.arcsinh(x.end)
+        return interval(start, end, is_valid=x.is_valid)
+    else:
+        return NotImplementedError
+
+
+def atanh(x):
+    """Evaluates the inverse hyperbolic tangent of an interval"""
+    np = import_module('numpy')
+    if isinstance(x, (int, float)):
+        #Outside the domain
+        if abs(x) >= 1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        else:
+            return interval(np.arctanh(x))
+    elif isinstance(x, interval):
+        #outside the domain
+        if x.is_valid is False or x.start >= 1 or x.end <= -1:
+            return interval(-np.inf, np.inf, is_valid=False)
+        #partly outside the domain
+        elif x.start <= -1 or x.end >= 1:
+            return interval(-np.inf, np.inf, is_valid=None)
+        else:
+            start = np.arctanh(x.start)
+            end = np.arctanh(x.end)
+            return interval(start, end, is_valid=x.is_valid)
+    else:
+        return NotImplementedError
+
+
+#Three valued logic for interval plotting.
+
+def And(*args):
+    """Defines the three valued ``And`` behaviour for a 2-tuple of
+     three valued logic values"""
+    def reduce_and(cmp_intervala, cmp_intervalb):
+        if cmp_intervala[0] is False or cmp_intervalb[0] is False:
+            first = False
+        elif cmp_intervala[0] is None or cmp_intervalb[0] is None:
+            first = None
+        else:
+            first = True
+        if cmp_intervala[1] is False or cmp_intervalb[1] is False:
+            second = False
+        elif cmp_intervala[1] is None or cmp_intervalb[1] is None:
+            second = None
+        else:
+            second = True
+        return (first, second)
+    return reduce(reduce_and, args)
+
+
+def Or(*args):
+    """Defines the three valued ``Or`` behaviour for a 2-tuple of
+     three valued logic values"""
+    def reduce_or(cmp_intervala, cmp_intervalb):
+        if cmp_intervala[0] is True or cmp_intervalb[0] is True:
+            first = True
+        elif cmp_intervala[0] is None or cmp_intervalb[0] is None:
+            first = None
+        else:
+            first = False
+
+        if cmp_intervala[1] is True or cmp_intervalb[1] is True:
+            second = True
+        elif cmp_intervala[1] is None or cmp_intervalb[1] is None:
+            second = None
+        else:
+            second = False
+        return (first, second)
+    return reduce(reduce_or, args)

rl/Lib/site-packages/sympy/plotting/intervalmath/tests/test_interval_functions.py

@@ -0,0 +1,415 @@
+from sympy.external import import_module
+from sympy.plotting.intervalmath import (
+    Abs, acos, acosh, And, asin, asinh, atan, atanh, ceil, cos, cosh,
+    exp, floor, imax, imin, interval, log, log10, Or, sin, sinh, sqrt,
+    tan, tanh,
+)
+
+np = import_module('numpy')
+if not np:
+    disabled = True
+
+
+#requires Numpy. Hence included in interval_functions
+
+
+def test_interval_pow():
+    a = 2**interval(1, 2) == interval(2, 4)
+    assert a == (True, True)
+    a = interval(1, 2)**interval(1, 2) == interval(1, 4)
+    assert a == (True, True)
+    a = interval(-1, 1)**interval(0.5, 2)
+    assert a.is_valid is None
+    a = interval(-2, -1) ** interval(1, 2)
+    assert a.is_valid is False
+    a = interval(-2, -1) ** (1.0 / 2)
+    assert a.is_valid is False
+    a = interval(-1, 1)**(1.0 / 2)
+    assert a.is_valid is None
+    a = interval(-1, 1)**(1.0 / 3) == interval(-1, 1)
+    assert a == (True, True)
+    a = interval(-1, 1)**2 == interval(0, 1)
+    assert a == (True, True)
+    a = interval(-1, 1) ** (1.0 / 29) == interval(-1, 1)
+    assert a == (True, True)
+    a = -2**interval(1, 1) == interval(-2, -2)
+    assert a == (True, True)
+
+    a = interval(1, 2, is_valid=False)**2
+    assert a.is_valid is False
+
+    a = (-3)**interval(1, 2)
+    assert a.is_valid is False
+    a = (-4)**interval(0.5, 0.5)
+    assert a.is_valid is False
+    assert ((-3)**interval(1, 1) == interval(-3, -3)) == (True, True)
+
+    a = interval(8, 64)**(2.0 / 3)
+    assert abs(a.start - 4) < 1e-10  # eps
+    assert abs(a.end - 16) < 1e-10
+    a = interval(-8, 64)**(2.0 / 3)
+    assert abs(a.start - 4) < 1e-10  # eps
+    assert abs(a.end - 16) < 1e-10
+
+
+def test_exp():
+    a = exp(interval(-np.inf, 0))
+    assert a.start == np.exp(-np.inf)
+    assert a.end == np.exp(0)
+    a = exp(interval(1, 2))
+    assert a.start == np.exp(1)
+    assert a.end == np.exp(2)
+    a = exp(1)
+    assert a.start == np.exp(1)
+    assert a.end == np.exp(1)
+
+
+def test_log():
+    a = log(interval(1, 2))
+    assert a.start == 0
+    assert a.end == np.log(2)
+    a = log(interval(-1, 1))
+    assert a.is_valid is None
+    a = log(interval(-3, -1))
+    assert a.is_valid is False
+    a = log(-3)
+    assert a.is_valid is False
+    a = log(2)
+    assert a.start == np.log(2)
+    assert a.end == np.log(2)
+
+
+def test_log10():
+    a = log10(interval(1, 2))
+    assert a.start == 0
+    assert a.end == np.log10(2)
+    a = log10(interval(-1, 1))
+    assert a.is_valid is None
+    a = log10(interval(-3, -1))
+    assert a.is_valid is False
+    a = log10(-3)
+    assert a.is_valid is False
+    a = log10(2)
+    assert a.start == np.log10(2)
+    assert a.end == np.log10(2)
+
+
+def test_atan():
+    a = atan(interval(0, 1))
+    assert a.start == np.arctan(0)
+    assert a.end == np.arctan(1)
+    a = atan(1)
+    assert a.start == np.arctan(1)
+    assert a.end == np.arctan(1)
+
+
+def test_sin():
+    a = sin(interval(0, np.pi / 4))
+    assert a.start == np.sin(0)
+    assert a.end == np.sin(np.pi / 4)
+
+    a = sin(interval(-np.pi / 4, np.pi / 4))
+    assert a.start == np.sin(-np.pi / 4)
+    assert a.end == np.sin(np.pi / 4)
+
+    a = sin(interval(np.pi / 4, 3 * np.pi / 4))
+    assert a.start == np.sin(np.pi / 4)
+    assert a.end == 1
+
+    a = sin(interval(7 * np.pi / 6, 7 * np.pi / 4))
+    assert a.start == -1
+    assert a.end == np.sin(7 * np.pi / 6)
+
+    a = sin(interval(0, 3 * np.pi))
+    assert a.start == -1
+    assert a.end == 1
+
+    a = sin(interval(np.pi / 3, 7 * np.pi / 4))
+    assert a.start == -1
+    assert a.end == 1
+
+    a = sin(np.pi / 4)
+    assert a.start == np.sin(np.pi / 4)
+    assert a.end == np.sin(np.pi / 4)
+
+    a = sin(interval(1, 2, is_valid=False))
+    assert a.is_valid is False
+
+
+def test_cos():
+    a = cos(interval(0, np.pi / 4))
+    assert a.start == np.cos(np.pi / 4)
+    assert a.end == 1
+
+    a = cos(interval(-np.pi / 4, np.pi / 4))
+    assert a.start == np.cos(-np.pi / 4)
+    assert a.end == 1
+
+    a = cos(interval(np.pi / 4, 3 * np.pi / 4))
+    assert a.start == np.cos(3 * np.pi / 4)
+    assert a.end == np.cos(np.pi / 4)
+
+    a = cos(interval(3 * np.pi / 4, 5 * np.pi / 4))
+    assert a.start == -1
+    assert a.end == np.cos(3 * np.pi / 4)
+
+    a = cos(interval(0, 3 * np.pi))
+    assert a.start == -1
+    assert a.end == 1
+
+    a = cos(interval(- np.pi / 3, 5 * np.pi / 4))
+    assert a.start == -1
+    assert a.end == 1
+
+    a = cos(interval(1, 2, is_valid=False))
+    assert a.is_valid is False
+
+
+def test_tan():
+    a = tan(interval(0, np.pi / 4))
+    assert a.start == 0
+    # must match lib_interval definition of tan:
+    assert a.end == np.sin(np.pi / 4)/np.cos(np.pi / 4)
+
+    a = tan(interval(np.pi / 4, 3 * np.pi / 4))
+    #discontinuity
+    assert a.is_valid is None
+
+
+def test_sqrt():
+    a = sqrt(interval(1, 4))
+    assert a.start == 1
+    assert a.end == 2
+
+    a = sqrt(interval(0.01, 1))
+    assert a.start == np.sqrt(0.01)
+    assert a.end == 1
+
+    a = sqrt(interval(-1, 1))
+    assert a.is_valid is None
+
+    a = sqrt(interval(-3, -1))
+    assert a.is_valid is False
+
+    a = sqrt(4)
+    assert (a == interval(2, 2)) == (True, True)
+
+    a = sqrt(-3)
+    assert a.is_valid is False
+
+
+def test_imin():
+    a = imin(interval(1, 3), interval(2, 5), interval(-1, 3))
+    assert a.start == -1
+    assert a.end == 3
+
+    a = imin(-2, interval(1, 4))
+    assert a.start == -2
+    assert a.end == -2
+
+    a = imin(5, interval(3, 4), interval(-2, 2, is_valid=False))
+    assert a.start == 3
+    assert a.end == 4
+
+
+def test_imax():
+    a = imax(interval(-2, 2), interval(2, 7), interval(-3, 9))
+    assert a.start == 2
+    assert a.end == 9
+
+    a = imax(8, interval(1, 4))
+    assert a.start == 8
+    assert a.end == 8
+
+    a = imax(interval(1, 2), interval(3, 4), interval(-2, 2, is_valid=False))
+    assert a.start == 3
+    assert a.end == 4
+
+
+def test_sinh():
+    a = sinh(interval(-1, 1))
+    assert a.start == np.sinh(-1)
+    assert a.end == np.sinh(1)
+
+    a = sinh(1)
+    assert a.start == np.sinh(1)
+    assert a.end == np.sinh(1)
+
+
+def test_cosh():
+    a = cosh(interval(1, 2))
+    assert a.start == np.cosh(1)
+    assert a.end == np.cosh(2)
+    a = cosh(interval(-2, -1))
+    assert a.start == np.cosh(-1)
+    assert a.end == np.cosh(-2)
+
+    a = cosh(interval(-2, 1))
+    assert a.start == 1
+    assert a.end == np.cosh(-2)
+
+    a = cosh(1)
+    assert a.start == np.cosh(1)
+    assert a.end == np.cosh(1)
+
+
+def test_tanh():
+    a = tanh(interval(-3, 3))
+    assert a.start == np.tanh(-3)
+    assert a.end == np.tanh(3)
+
+    a = tanh(3)
+    assert a.start == np.tanh(3)
+    assert a.end == np.tanh(3)
+
+
+def test_asin():
+    a = asin(interval(-0.5, 0.5))
+    assert a.start == np.arcsin(-0.5)
+    assert a.end == np.arcsin(0.5)
+
+    a = asin(interval(-1.5, 1.5))
+    assert a.is_valid is None
+    a = asin(interval(-2, -1.5))
+    assert a.is_valid is False
+
+    a = asin(interval(0, 2))
+    assert a.is_valid is None
+
+    a = asin(interval(2, 5))
+    assert a.is_valid is False
+
+    a = asin(0.5)
+    assert a.start == np.arcsin(0.5)
+    assert a.end == np.arcsin(0.5)
+
+    a = asin(1.5)
+    assert a.is_valid is False
+
+
+def test_acos():
+    a = acos(interval(-0.5, 0.5))
+    assert a.start == np.arccos(0.5)
+    assert a.end == np.arccos(-0.5)
+
+    a = acos(interval(-1.5, 1.5))
+    assert a.is_valid is None
+    a = acos(interval(-2, -1.5))
+    assert a.is_valid is False
+
+    a = acos(interval(0, 2))
+    assert a.is_valid is None
+
+    a = acos(interval(2, 5))
+    assert a.is_valid is False
+
+    a = acos(0.5)
+    assert a.start == np.arccos(0.5)
+    assert a.end == np.arccos(0.5)
+
+    a = acos(1.5)
+    assert a.is_valid is False
+
+
+def test_ceil():
+    a = ceil(interval(0.2, 0.5))
+    assert a.start == 1
+    assert a.end == 1
+
+    a = ceil(interval(0.5, 1.5))
+    assert a.start == 1
+    assert a.end == 2
+    assert a.is_valid is None
+
+    a = ceil(interval(-5, 5))
+    assert a.is_valid is None
+
+    a = ceil(5.4)
+    assert a.start == 6
+    assert a.end == 6
+
+
+def test_floor():
+    a = floor(interval(0.2, 0.5))
+    assert a.start == 0
+    assert a.end == 0
+
+    a = floor(interval(0.5, 1.5))
+    assert a.start == 0
+    assert a.end == 1
+    assert a.is_valid is None
+
+    a = floor(interval(-5, 5))
+    assert a.is_valid is None
+
+    a = floor(5.4)
+    assert a.start == 5
+    assert a.end == 5
+
+
+def test_asinh():
+    a = asinh(interval(1, 2))
+    assert a.start == np.arcsinh(1)
+    assert a.end == np.arcsinh(2)
+
+    a = asinh(0.5)
+    assert a.start == np.arcsinh(0.5)
+    assert a.end == np.arcsinh(0.5)
+
+
+def test_acosh():
+    a = acosh(interval(3, 5))
+    assert a.start == np.arccosh(3)
+    assert a.end == np.arccosh(5)
+
+    a = acosh(interval(0, 3))
+    assert a.is_valid is None
+    a = acosh(interval(-3, 0.5))
+    assert a.is_valid is False
+
+    a = acosh(0.5)
+    assert a.is_valid is False
+
+    a = acosh(2)
+    assert a.start == np.arccosh(2)
+    assert a.end == np.arccosh(2)
+
+
+def test_atanh():
+    a = atanh(interval(-0.5, 0.5))
+    assert a.start == np.arctanh(-0.5)
+    assert a.end == np.arctanh(0.5)
+
+    a = atanh(interval(0, 3))
+    assert a.is_valid is None
+
+    a = atanh(interval(-3, -2))
+    assert a.is_valid is False
+
+    a = atanh(0.5)
+    assert a.start == np.arctanh(0.5)
+    assert a.end == np.arctanh(0.5)
+
+    a = atanh(1.5)
+    assert a.is_valid is False
+
+
+def test_Abs():
+    assert (Abs(interval(-0.5, 0.5)) == interval(0, 0.5)) == (True, True)
+    assert (Abs(interval(-3, -2)) == interval(2, 3)) == (True, True)
+    assert (Abs(-3) == interval(3, 3)) == (True, True)
+
+
+def test_And():
+    args = [(True, True), (True, False), (True, None)]
+    assert And(*args) == (True, False)
+
+    args = [(False, True), (None, None), (True, True)]
+    assert And(*args) == (False, None)
+
+
+def test_Or():
+    args = [(True, True), (True, False), (False, None)]
+    assert Or(*args) == (True, True)
+    args = [(None, None), (False, None), (False, False)]
+    assert Or(*args) == (None, None)

rl/Lib/site-packages/sympy/plotting/intervalmath/tests/test_interval_membership.py

@@ -0,0 +1,150 @@
+from sympy.core.symbol import Symbol
+from sympy.plotting.intervalmath import interval
+from sympy.plotting.intervalmath.interval_membership import intervalMembership
+from sympy.plotting.experimental_lambdify import experimental_lambdify
+from sympy.testing.pytest import raises
+
+
+def test_creation():
+    assert intervalMembership(True, True)
+    raises(TypeError, lambda: intervalMembership(True))
+    raises(TypeError, lambda: intervalMembership(True, True, True))
+
+
+def test_getitem():
+    a = intervalMembership(True, False)
+    assert a[0] is True
+    assert a[1] is False
+    raises(IndexError, lambda: a[2])
+
+
+def test_str():
+    a = intervalMembership(True, False)
+    assert str(a) == 'intervalMembership(True, False)'
+    assert repr(a) == 'intervalMembership(True, False)'
+
+
+def test_equivalence():
+    a = intervalMembership(True, True)
+    b = intervalMembership(True, False)
+    assert (a == b) is False
+    assert (a != b) is True
+
+    a = intervalMembership(True, False)
+    b = intervalMembership(True, False)
+    assert (a == b) is True
+    assert (a != b) is False
+
+
+def test_not():
+    x = Symbol('x')
+
+    r1 = x > -1
+    r2 = x <= -1
+
+    i = interval
+
+    f1 = experimental_lambdify((x,), r1)
+    f2 = experimental_lambdify((x,), r2)
+
+    tt = i(-0.1, 0.1, is_valid=True)
+    tn = i(-0.1, 0.1, is_valid=None)
+    tf = i(-0.1, 0.1, is_valid=False)
+
+    assert f1(tt) == ~f2(tt)
+    assert f1(tn) == ~f2(tn)
+    assert f1(tf) == ~f2(tf)
+
+    nt = i(0.9, 1.1, is_valid=True)
+    nn = i(0.9, 1.1, is_valid=None)
+    nf = i(0.9, 1.1, is_valid=False)
+
+    assert f1(nt) == ~f2(nt)
+    assert f1(nn) == ~f2(nn)
+    assert f1(nf) == ~f2(nf)
+
+    ft = i(1.9, 2.1, is_valid=True)
+    fn = i(1.9, 2.1, is_valid=None)
+    ff = i(1.9, 2.1, is_valid=False)
+
+    assert f1(ft) == ~f2(ft)
+    assert f1(fn) == ~f2(fn)
+    assert f1(ff) == ~f2(ff)
+
+
+def test_boolean():
+    # There can be 9*9 test cases in full mapping of the cartesian product.
+    # But we only consider 3*3 cases for simplicity.
+    s = [
+        intervalMembership(False, False),
+        intervalMembership(None, None),
+        intervalMembership(True, True)
+    ]
+
+    # Reduced tests for 'And'
+    a1 = [
+        intervalMembership(False, False),
+        intervalMembership(False, False),
+        intervalMembership(False, False),
+        intervalMembership(False, False),
+        intervalMembership(None, None),
+        intervalMembership(None, None),
+        intervalMembership(False, False),
+        intervalMembership(None, None),
+        intervalMembership(True, True)
+    ]
+    a1_iter = iter(a1)
+    for i in range(len(s)):
+        for j in range(len(s)):
+            assert s[i] & s[j] == next(a1_iter)
+
+    # Reduced tests for 'Or'
+    a1 = [
+        intervalMembership(False, False),
+        intervalMembership(None, False),
+        intervalMembership(True, False),
+        intervalMembership(None, False),
+        intervalMembership(None, None),
+        intervalMembership(True, None),
+        intervalMembership(True, False),
+        intervalMembership(True, None),
+        intervalMembership(True, True)
+    ]
+    a1_iter = iter(a1)
+    for i in range(len(s)):
+        for j in range(len(s)):
+            assert s[i] | s[j] == next(a1_iter)
+
+    # Reduced tests for 'Xor'
+    a1 = [
+        intervalMembership(False, False),
+        intervalMembership(None, False),
+        intervalMembership(True, False),
+        intervalMembership(None, False),
+        intervalMembership(None, None),
+        intervalMembership(None, None),
+        intervalMembership(True, False),
+        intervalMembership(None, None),
+        intervalMembership(False, True)
+    ]
+    a1_iter = iter(a1)
+    for i in range(len(s)):
+        for j in range(len(s)):
+            assert s[i] ^ s[j] == next(a1_iter)
+
+    # Reduced tests for 'Not'
+    a1 = [
+        intervalMembership(True, False),
+        intervalMembership(None, None),
+        intervalMembership(False, True)
+    ]
+    a1_iter = iter(a1)
+    for i in range(len(s)):
+        assert ~s[i] == next(a1_iter)
+
+
+def test_boolean_errors():
+    a = intervalMembership(True, True)
+    raises(ValueError, lambda: a & 1)
+    raises(ValueError, lambda: a | 1)
+    raises(ValueError, lambda: a ^ 1)

rl/Lib/site-packages/sympy/plotting/intervalmath/tests/test_intervalmath.py

@@ -0,0 +1,213 @@
+from sympy.plotting.intervalmath import interval
+from sympy.testing.pytest import raises
+
+
+def test_interval():
+    assert (interval(1, 1) == interval(1, 1, is_valid=True)) == (True, True)
+    assert (interval(1, 1) == interval(1, 1, is_valid=False)) == (True, False)
+    assert (interval(1, 1) == interval(1, 1, is_valid=None)) == (True, None)
+    assert (interval(1, 1.5) == interval(1, 2)) == (None, True)
+    assert (interval(0, 1) == interval(2, 3)) == (False, True)
+    assert (interval(0, 1) == interval(1, 2)) == (None, True)
+    assert (interval(1, 2) != interval(1, 2)) == (False, True)
+    assert (interval(1, 3) != interval(2, 3)) == (None, True)
+    assert (interval(1, 3) != interval(-5, -3)) == (True, True)
+    assert (
+        interval(1, 3, is_valid=False) != interval(-5, -3)) == (True, False)
+    assert (interval(1, 3, is_valid=None) != interval(-5, 3)) == (None, None)
+    assert (interval(4, 4) != 4) == (False, True)
+    assert (interval(1, 1) == 1) == (True, True)
+    assert (interval(1, 3, is_valid=False) == interval(1, 3)) == (True, False)
+    assert (interval(1, 3, is_valid=None) == interval(1, 3)) == (True, None)
+    inter = interval(-5, 5)
+    assert (interval(inter) == interval(-5, 5)) == (True, True)
+    assert inter.width == 10
+    assert 0 in inter
+    assert -5 in inter
+    assert 5 in inter
+    assert interval(0, 3) in inter
+    assert interval(-6, 2) not in inter
+    assert -5.05 not in inter
+    assert 5.3 not in inter
+    interb = interval(-float('inf'), float('inf'))
+    assert 0 in inter
+    assert inter in interb
+    assert interval(0, float('inf')) in interb
+    assert interval(-float('inf'), 5) in interb
+    assert interval(-1e50, 1e50) in interb
+    assert (
+        -interval(-1, -2, is_valid=False) == interval(1, 2)) == (True, False)
+    raises(ValueError, lambda: interval(1, 2, 3))
+
+
+def test_interval_add():
+    assert (interval(1, 2) + interval(2, 3) == interval(3, 5)) == (True, True)
+    assert (1 + interval(1, 2) == interval(2, 3)) == (True, True)
+    assert (interval(1, 2) + 1 == interval(2, 3)) == (True, True)
+    compare = (1 + interval(0, float('inf')) == interval(1, float('inf')))
+    assert compare == (True, True)
+    a = 1 + interval(2, 5, is_valid=False)
+    assert a.is_valid is False
+    a = 1 + interval(2, 5, is_valid=None)
+    assert a.is_valid is None
+    a = interval(2, 5, is_valid=False) + interval(3, 5, is_valid=None)
+    assert a.is_valid is False
+    a = interval(3, 5) + interval(-1, 1, is_valid=None)
+    assert a.is_valid is None
+    a = interval(2, 5, is_valid=False) + 1
+    assert a.is_valid is False
+
+
+def test_interval_sub():
+    assert (interval(1, 2) - interval(1, 5) == interval(-4, 1)) == (True, True)
+    assert (interval(1, 2) - 1 == interval(0, 1)) == (True, True)
+    assert (1 - interval(1, 2) == interval(-1, 0)) == (True, True)
+    a = 1 - interval(1, 2, is_valid=False)
+    assert a.is_valid is False
+    a = interval(1, 4, is_valid=None) - 1
+    assert a.is_valid is None
+    a = interval(1, 3, is_valid=False) - interval(1, 3)
+    assert a.is_valid is False
+    a = interval(1, 3, is_valid=None) - interval(1, 3)
+    assert a.is_valid is None
+
+
+def test_interval_inequality():
+    assert (interval(1, 2) < interval(3, 4)) == (True, True)
+    assert (interval(1, 2) < interval(2, 4)) == (None, True)
+    assert (interval(1, 2) < interval(-2, 0)) == (False, True)
+    assert (interval(1, 2) <= interval(2, 4)) == (True, True)
+    assert (interval(1, 2) <= interval(1.5, 6)) == (None, True)
+    assert (interval(2, 3) <= interval(1, 2)) == (None, True)
+    assert (interval(2, 3) <= interval(1, 1.5)) == (False, True)
+    assert (
+        interval(1, 2, is_valid=False) <= interval(-2, 0)) == (False, False)
+    assert (interval(1, 2, is_valid=None) <= interval(-2, 0)) == (False, None)
+    assert (interval(1, 2) <= 1.5) == (None, True)
+    assert (interval(1, 2) <= 3) == (True, True)
+    assert (interval(1, 2) <= 0) == (False, True)
+    assert (interval(5, 8) > interval(2, 3)) == (True, True)
+    assert (interval(2, 5) > interval(1, 3)) == (None, True)
+    assert (interval(2, 3) > interval(3.1, 5)) == (False, True)
+
+    assert (interval(-1, 1) == 0) == (None, True)
+    assert (interval(-1, 1) == 2) == (False, True)
+    assert (interval(-1, 1) != 0) == (None, True)
+    assert (interval(-1, 1) != 2) == (True, True)
+
+    assert (interval(3, 5) > 2) == (True, True)
+    assert (interval(3, 5) < 2) == (False, True)
+    assert (interval(1, 5) < 2) == (None, True)
+    assert (interval(1, 5) > 2) == (None, True)
+    assert (interval(0, 1) > 2) == (False, True)
+    assert (interval(1, 2) >= interval(0, 1)) == (True, True)
+    assert (interval(1, 2) >= interval(0, 1.5)) == (None, True)
+    assert (interval(1, 2) >= interval(3, 4)) == (False, True)
+    assert (interval(1, 2) >= 0) == (True, True)
+    assert (interval(1, 2) >= 1.2) == (None, True)
+    assert (interval(1, 2) >= 3) == (False, True)
+    assert (2 > interval(0, 1)) == (True, True)
+    a = interval(-1, 1, is_valid=False) < interval(2, 5, is_valid=None)
+    assert a == (True, False)
+    a = interval(-1, 1, is_valid=None) < interval(2, 5, is_valid=False)
+    assert a == (True, False)
+    a = interval(-1, 1, is_valid=None) < interval(2, 5, is_valid=None)
+    assert a == (True, None)
+    a = interval(-1, 1, is_valid=False) > interval(-5, -2, is_valid=None)
+    assert a == (True, False)
+    a = interval(-1, 1, is_valid=None) > interval(-5, -2, is_valid=False)
+    assert a == (True, False)
+    a = interval(-1, 1, is_valid=None) > interval(-5, -2, is_valid=None)
+    assert a == (True, None)
+
+
+def test_interval_mul():
+    assert (
+        interval(1, 5) * interval(2, 10) == interval(2, 50)) == (True, True)
+    a = interval(-1, 1) * interval(2, 10) == interval(-10, 10)
+    assert a == (True, True)
+
+    a = interval(-1, 1) * interval(-5, 3) == interval(-5, 5)
+    assert a == (True, True)
+
+    assert (interval(1, 3) * 2 == interval(2, 6)) == (True, True)
+    assert (3 * interval(-1, 2) == interval(-3, 6)) == (True, True)
+
+    a = 3 * interval(1, 2, is_valid=False)
+    assert a.is_valid is False
+
+    a = 3 * interval(1, 2, is_valid=None)
+    assert a.is_valid is None
+
+    a = interval(1, 5, is_valid=False) * interval(1, 2, is_valid=None)
+    assert a.is_valid is False
+
+
+def test_interval_div():
+    div = interval(1, 2, is_valid=False) / 3
+    assert div == interval(-float('inf'), float('inf'), is_valid=False)
+
+    div = interval(1, 2, is_valid=None) / 3
+    assert div == interval(-float('inf'), float('inf'), is_valid=None)
+
+    div = 3 / interval(1, 2, is_valid=None)
+    assert div == interval(-float('inf'), float('inf'), is_valid=None)
+    a = interval(1, 2) / 0
+    assert a.is_valid is False
+    a = interval(0.5, 1) / interval(-1, 0)
+    assert a.is_valid is None
+    a = interval(0, 1) / interval(0, 1)
+    assert a.is_valid is None
+
+    a = interval(-1, 1) / interval(-1, 1)
+    assert a.is_valid is None
+
+    a = interval(-1, 2) / interval(0.5, 1) == interval(-2.0, 4.0)
+    assert a == (True, True)
+    a = interval(0, 1) / interval(0.5, 1) == interval(0.0, 2.0)
+    assert a == (True, True)
+    a = interval(-1, 0) / interval(0.5, 1) == interval(-2.0, 0.0)
+    assert a == (True, True)
+    a = interval(-0.5, -0.25) / interval(0.5, 1) == interval(-1.0, -0.25)
+    assert a == (True, True)
+    a = interval(0.5, 1) / interval(0.5, 1) == interval(0.5, 2.0)
+    assert a == (True, True)
+    a = interval(0.5, 4) / interval(0.5, 1) == interval(0.5, 8.0)
+    assert a == (True, True)
+    a = interval(-1, -0.5) / interval(0.5, 1) == interval(-2.0, -0.5)
+    assert a == (True, True)
+    a = interval(-4, -0.5) / interval(0.5, 1) == interval(-8.0, -0.5)
+    assert a == (True, True)
+    a = interval(-1, 2) / interval(-2, -0.5) == interval(-4.0, 2.0)
+    assert a == (True, True)
+    a = interval(0, 1) / interval(-2, -0.5) == interval(-2.0, 0.0)
+    assert a == (True, True)
+    a = interval(-1, 0) / interval(-2, -0.5) == interval(0.0, 2.0)
+    assert a == (True, True)
+    a = interval(-0.5, -0.25) / interval(-2, -0.5) == interval(0.125, 1.0)
+    assert a == (True, True)
+    a = interval(0.5, 1) / interval(-2, -0.5) == interval(-2.0, -0.25)
+    assert a == (True, True)
+    a = interval(0.5, 4) / interval(-2, -0.5) == interval(-8.0, -0.25)
+    assert a == (True, True)
+    a = interval(-1, -0.5) / interval(-2, -0.5) == interval(0.25, 2.0)
+    assert a == (True, True)
+    a = interval(-4, -0.5) / interval(-2, -0.5) == interval(0.25, 8.0)
+    assert a == (True, True)
+    a = interval(-5, 5, is_valid=False) / 2
+    assert a.is_valid is False
+
+def test_hashable():
+    '''
+    test that interval objects are hashable.
+    this is required in order to be able to put them into the cache, which
+    appears to be necessary for plotting in py3k. For details, see:
+
+    https://github.com/sympy/sympy/pull/2101
+    https://github.com/sympy/sympy/issues/6533
+    '''
+    hash(interval(1, 1))
+    hash(interval(1, 1, is_valid=True))
+    hash(interval(-4, -0.5))
+    hash(interval(-2, -0.5))
+    hash(interval(0.25, 8.0))