I am done

rl/Lib/site-packages/sympy/liealgebras/__init__.py

@@ -0,0 +1,3 @@
+from sympy.liealgebras.cartan_type import CartanType
+
+__all__ = ['CartanType']

rl/Lib/site-packages/sympy/liealgebras/cartan_matrix.py

@@ -0,0 +1,25 @@
+from .cartan_type import CartanType
+
+def CartanMatrix(ct):
+    """Access the Cartan matrix of a specific Lie algebra
+
+    Examples
+    ========
+
+    >>> from sympy.liealgebras.cartan_matrix import CartanMatrix
+    >>> CartanMatrix("A2")
+    Matrix([
+    [ 2, -1],
+    [-1,  2]])
+
+    >>> CartanMatrix(['C', 3])
+    Matrix([
+    [ 2, -1,  0],
+    [-1,  2, -1],
+    [ 0, -2,  2]])
+
+    This method works by returning the Cartan matrix
+    which corresponds to Cartan type t.
+    """
+
+    return CartanType(ct).cartan_matrix()

rl/Lib/site-packages/sympy/liealgebras/cartan_type.py

@@ -0,0 +1,73 @@
+from sympy.core import Atom, Basic
+
+
+class CartanType_generator():
+    """
+    Constructor for actually creating things
+    """
+    def __call__(self, *args):
+        c = args[0]
+        if isinstance(c, list):
+            letter, n = c[0], int(c[1])
+        elif isinstance(c, str):
+            letter, n = c[0], int(c[1:])
+        else:
+            raise TypeError("Argument must be a string (e.g. 'A3') or a list (e.g. ['A', 3])")
+
+        if n < 0:
+            raise ValueError("Lie algebra rank cannot be negative")
+        if letter == "A":
+            from . import type_a
+            return type_a.TypeA(n)
+        if letter == "B":
+            from . import type_b
+            return type_b.TypeB(n)
+
+        if letter == "C":
+            from . import type_c
+            return type_c.TypeC(n)
+
+        if letter == "D":
+            from . import type_d
+            return type_d.TypeD(n)
+
+        if letter == "E":
+            if n >= 6 and n <= 8:
+                from . import type_e
+                return type_e.TypeE(n)
+
+        if letter == "F":
+            if n == 4:
+                from . import type_f
+                return type_f.TypeF(n)
+
+        if letter == "G":
+            if n == 2:
+                from . import type_g
+                return type_g.TypeG(n)
+
+CartanType = CartanType_generator()
+
+
+class Standard_Cartan(Atom):
+    """
+    Concrete base class for Cartan types such as A4, etc
+    """
+
+    def __new__(cls, series, n):
+        obj = Basic.__new__(cls)
+        obj.n = n
+        obj.series = series
+        return obj
+
+    def rank(self):
+        """
+        Returns the rank of the Lie algebra
+        """
+        return self.n
+
+    def series(self):
+        """
+        Returns the type of the Lie algebra
+        """
+        return self.series

rl/Lib/site-packages/sympy/liealgebras/dynkin_diagram.py

@@ -0,0 +1,24 @@
+from .cartan_type import CartanType
+
+
+def DynkinDiagram(t):
+    """Display the Dynkin diagram of a given Lie algebra
+
+    Works by generating the CartanType for the input, t, and then returning the
+    Dynkin diagram method from the individual classes.
+
+    Examples
+    ========
+
+    >>> from sympy.liealgebras.dynkin_diagram import DynkinDiagram
+    >>> print(DynkinDiagram("A3"))
+    0---0---0
+    1   2   3
+
+    >>> print(DynkinDiagram("B4"))
+    0---0---0=>=0
+    1   2   3   4
+
+    """
+
+    return CartanType(t).dynkin_diagram()

rl/Lib/site-packages/sympy/liealgebras/root_system.py

@@ -0,0 +1,199 @@
+from .cartan_type import CartanType
+from sympy.core.basic import Atom
+
+class RootSystem(Atom):
+    """Represent the root system of a simple Lie algebra
+
+    Every simple Lie algebra has a unique root system.  To find the root
+    system, we first consider the Cartan subalgebra of g, which is the maximal
+    abelian subalgebra, and consider the adjoint action of g on this
+    subalgebra.  There is a root system associated with this action. Now, a
+    root system over a vector space V is a set of finite vectors Phi (called
+    roots), which satisfy:
+
+    1.  The roots span V
+    2.  The only scalar multiples of x in Phi are x and -x
+    3.  For every x in Phi, the set Phi is closed under reflection
+        through the hyperplane perpendicular to x.
+    4.  If x and y are roots in Phi, then the projection of y onto
+        the line through x is a half-integral multiple of x.
+
+    Now, there is a subset of Phi, which we will call Delta, such that:
+    1.  Delta is a basis of V
+    2.  Each root x in Phi can be written x = sum k_y y for y in Delta
+
+    The elements of Delta are called the simple roots.
+    Therefore, we see that the simple roots span the root space of a given
+    simple Lie algebra.
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Root_system
+    .. [2] Lie Algebras and Representation Theory - Humphreys
+
+    """
+
+    def __new__(cls, cartantype):
+        """Create a new RootSystem object
+
+        This method assigns an attribute called cartan_type to each instance of
+        a RootSystem object.  When an instance of RootSystem is called, it
+        needs an argument, which should be an instance of a simple Lie algebra.
+        We then take the CartanType of this argument and set it as the
+        cartan_type attribute of the RootSystem instance.
+
+        """
+        obj = Atom.__new__(cls)
+        obj.cartan_type = CartanType(cartantype)
+        return obj
+
+    def simple_roots(self):
+        """Generate the simple roots of the Lie algebra
+
+        The rank of the Lie algebra determines the number of simple roots that
+        it has.  This method obtains the rank of the Lie algebra, and then uses
+        the simple_root method from the Lie algebra classes to generate all the
+        simple roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> roots = c.simple_roots()
+        >>> roots
+        {1: [1, -1, 0, 0], 2: [0, 1, -1, 0], 3: [0, 0, 1, -1]}
+
+        """
+        n = self.cartan_type.rank()
+        roots = {}
+        for i in range(1, n+1):
+            root = self.cartan_type.simple_root(i)
+            roots[i] = root
+        return roots
+
+
+    def all_roots(self):
+        """Generate all the roots of a given root system
+
+        The result is a dictionary where the keys are integer numbers.  It
+        generates the roots by getting the dictionary of all positive roots
+        from the bases classes, and then taking each root, and multiplying it
+        by -1 and adding it to the dictionary.  In this way all the negative
+        roots are generated.
+
+        """
+        alpha = self.cartan_type.positive_roots()
+        keys = list(alpha.keys())
+        k = max(keys)
+        for val in keys:
+            k += 1
+            root = alpha[val]
+            newroot = [-x for x in root]
+            alpha[k] = newroot
+        return alpha
+
+    def root_space(self):
+        """Return the span of the simple roots
+
+        The root space is the vector space spanned by the simple roots, i.e. it
+        is a vector space with a distinguished basis, the simple roots.  This
+        method returns a string that represents the root space as the span of
+        the simple roots, alpha[1],...., alpha[n].
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> c.root_space()
+        'alpha[1] + alpha[2] + alpha[3]'
+
+        """
+        n = self.cartan_type.rank()
+        rs = " + ".join("alpha["+str(i) +"]" for i in range(1, n+1))
+        return rs
+
+    def add_simple_roots(self, root1, root2):
+        """Add two simple roots together
+
+        The function takes as input two integers, root1 and root2.  It then
+        uses these integers as keys in the dictionary of simple roots, and gets
+        the corresponding simple roots, and then adds them together.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> newroot = c.add_simple_roots(1, 2)
+        >>> newroot
+        [1, 0, -1, 0]
+
+        """
+
+        alpha = self.simple_roots()
+        if root1 > len(alpha) or root2 > len(alpha):
+            raise ValueError("You've used a root that doesn't exist!")
+        a1 = alpha[root1]
+        a2 = alpha[root2]
+        newroot = [_a1 + _a2 for _a1, _a2 in zip(a1, a2)]
+        return newroot
+
+    def add_as_roots(self, root1, root2):
+        """Add two roots together if and only if their sum is also a root
+
+        It takes as input two vectors which should be roots.  It then computes
+        their sum and checks if it is in the list of all possible roots.  If it
+        is, it returns the sum.  Otherwise it returns a string saying that the
+        sum is not a root.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> c.add_as_roots([1, 0, -1, 0], [0, 0, 1, -1])
+        [1, 0, 0, -1]
+        >>> c.add_as_roots([1, -1, 0, 0], [0, 0, -1, 1])
+        'The sum of these two roots is not a root'
+
+        """
+        alpha = self.all_roots()
+        newroot = [r1 + r2 for r1, r2 in zip(root1, root2)]
+        if newroot in alpha.values():
+            return newroot
+        else:
+            return "The sum of these two roots is not a root"
+
+
+    def cartan_matrix(self):
+        """Cartan matrix of Lie algebra associated with this root system
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> c.cartan_matrix()
+        Matrix([
+            [ 2, -1,  0],
+            [-1,  2, -1],
+            [ 0, -1,  2]])
+        """
+        return self.cartan_type.cartan_matrix()
+
+    def dynkin_diagram(self):
+        """Dynkin diagram of the Lie algebra associated with this root system
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.root_system import RootSystem
+        >>> c = RootSystem("A3")
+        >>> print(c.dynkin_diagram())
+        0---0---0
+        1   2   3
+        """
+        return self.cartan_type.dynkin_diagram()

rl/Lib/site-packages/sympy/liealgebras/tests/test_cartan_matrix.py

@@ -0,0 +1,10 @@
+from sympy.liealgebras.cartan_matrix import CartanMatrix
+from sympy.matrices import Matrix
+
+def test_CartanMatrix():
+    c = CartanMatrix("A3")
+    m = Matrix(3, 3, [2, -1, 0, -1, 2, -1, 0, -1, 2])
+    assert c == m
+    a = CartanMatrix(["G",2])
+    mt = Matrix(2, 2, [2, -1, -3, 2])
+    assert a == mt

rl/Lib/site-packages/sympy/liealgebras/tests/test_cartan_type.py

@@ -0,0 +1,12 @@
+from sympy.liealgebras.cartan_type import CartanType, Standard_Cartan
+
+def test_Standard_Cartan():
+    c = CartanType("A4")
+    assert c.rank() == 4
+    assert c.series == "A"
+    m = Standard_Cartan("A", 2)
+    assert m.rank() == 2
+    assert m.series == "A"
+    b = CartanType("B12")
+    assert b.rank() == 12
+    assert b.series == "B"

rl/Lib/site-packages/sympy/liealgebras/tests/test_dynkin_diagram.py

@@ -0,0 +1,9 @@
+from sympy.liealgebras.dynkin_diagram import DynkinDiagram
+
+def test_DynkinDiagram():
+    c = DynkinDiagram("A3")
+    diag = "0---0---0\n1   2   3"
+    assert c == diag
+    ct = DynkinDiagram(["B", 3])
+    diag2 = "0---0=>=0\n1   2   3"
+    assert ct == diag2

rl/Lib/site-packages/sympy/liealgebras/tests/test_root_system.py

@@ -0,0 +1,18 @@
+from sympy.liealgebras.root_system import RootSystem
+from sympy.liealgebras.type_a import TypeA
+from sympy.matrices import Matrix
+
+def test_root_system():
+    c = RootSystem("A3")
+    assert c.cartan_type == TypeA(3)
+    assert c.simple_roots() ==  {1: [1, -1, 0, 0], 2: [0, 1, -1, 0], 3: [0, 0, 1, -1]}
+    assert c.root_space() == "alpha[1] + alpha[2] + alpha[3]"
+    assert c.cartan_matrix() == Matrix([[ 2, -1,  0], [-1,  2, -1], [ 0, -1,  2]])
+    assert c.dynkin_diagram() == "0---0---0\n1   2   3"
+    assert c.add_simple_roots(1, 2) == [1, 0, -1, 0]
+    assert c.all_roots() == {1: [1, -1, 0, 0], 2: [1, 0, -1, 0],
+            3: [1, 0, 0, -1], 4: [0, 1, -1, 0], 5: [0, 1, 0, -1],
+            6: [0, 0, 1, -1], 7: [-1, 1, 0, 0], 8: [-1, 0, 1, 0],
+            9: [-1, 0, 0, 1], 10: [0, -1, 1, 0],
+            11: [0, -1, 0, 1], 12: [0, 0, -1, 1]}
+    assert c.add_as_roots([1, 0, -1, 0], [0, 0, 1, -1]) == [1, 0, 0, -1]

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_A.py

@@ -0,0 +1,17 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+def test_type_A():
+    c = CartanType("A3")
+    m = Matrix(3, 3, [2, -1, 0, -1, 2, -1, 0, -1, 2])
+    assert m == c.cartan_matrix()
+    assert c.basis() == 8
+    assert c.roots() == 12
+    assert c.dimension() == 4
+    assert c.simple_root(1) == [1, -1, 0, 0]
+    assert c.highest_root() == [1, 0, 0, -1]
+    assert c.lie_algebra() == "su(4)"
+    diag = "0---0---0\n1   2   3"
+    assert c.dynkin_diagram() == diag
+    assert c.positive_roots() == {1: [1, -1, 0, 0], 2: [1, 0, -1, 0],
+            3: [1, 0, 0, -1], 4: [0, 1, -1, 0], 5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_B.py

@@ -0,0 +1,17 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+def test_type_B():
+    c = CartanType("B3")
+    m = Matrix(3, 3, [2, -1, 0, -1, 2, -2, 0, -1, 2])
+    assert m == c.cartan_matrix()
+    assert c.dimension() == 3
+    assert c.roots() == 18
+    assert c.simple_root(3) == [0, 0, 1]
+    assert c.basis() == 3
+    assert c.lie_algebra() == "so(6)"
+    diag = "0---0=>=0\n1   2   3"
+    assert c.dynkin_diagram() == diag
+    assert c.positive_roots() ==  {1: [1, -1, 0], 2: [1, 1, 0], 3: [1, 0, -1],
+            4: [1, 0, 1], 5: [0, 1, -1], 6: [0, 1, 1], 7: [1, 0, 0],
+            8: [0, 1, 0], 9: [0, 0, 1]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_C.py

@@ -0,0 +1,22 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+def test_type_C():
+    c = CartanType("C4")
+    m = Matrix(4, 4, [2, -1, 0, 0, -1, 2, -1, 0, 0, -1, 2, -1, 0, 0, -2, 2])
+    assert c.cartan_matrix() == m
+    assert c.dimension() == 4
+    assert c.simple_root(4) == [0, 0, 0, 2]
+    assert c.roots() == 32
+    assert c.basis() == 36
+    assert c.lie_algebra() == "sp(8)"
+    t = CartanType(['C', 3])
+    assert t.dimension() == 3
+    diag = "0---0---0=<=0\n1   2   3   4"
+    assert c.dynkin_diagram() == diag
+    assert c.positive_roots() == {1: [1, -1, 0, 0], 2: [1, 1, 0, 0],
+            3: [1, 0, -1, 0], 4: [1, 0, 1, 0], 5: [1, 0, 0, -1],
+            6: [1, 0, 0, 1], 7: [0, 1, -1, 0], 8: [0, 1, 1, 0],
+            9: [0, 1, 0, -1], 10: [0, 1, 0, 1], 11: [0, 0, 1, -1],
+            12: [0, 0, 1, 1], 13: [2, 0, 0, 0], 14: [0, 2, 0, 0], 15: [0, 0, 2, 0],
+            16: [0, 0, 0, 2]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_D.py

@@ -0,0 +1,19 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+
+
+def test_type_D():
+    c = CartanType("D4")
+    m = Matrix(4, 4, [2, -1, 0, 0, -1, 2, -1, -1, 0, -1, 2, 0, 0, -1, 0, 2])
+    assert c.cartan_matrix() == m
+    assert c.basis() == 6
+    assert c.lie_algebra() == "so(8)"
+    assert c.roots() == 24
+    assert c.simple_root(3) == [0, 0, 1, -1]
+    diag = "    3\n    0\n    |\n    |\n0---0---0\n1   2   4"
+    assert diag == c.dynkin_diagram()
+    assert c.positive_roots() == {1: [1, -1, 0, 0], 2: [1, 1, 0, 0],
+            3: [1, 0, -1, 0], 4: [1, 0, 1, 0], 5: [1, 0, 0, -1], 6: [1, 0, 0, 1],
+            7: [0, 1, -1, 0], 8: [0, 1, 1, 0], 9: [0, 1, 0, -1], 10: [0, 1, 0, 1],
+            11: [0, 0, 1, -1], 12: [0, 0, 1, 1]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_E.py

@@ -0,0 +1,19 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+def test_type_E():
+    c = CartanType("E6")
+    m = Matrix(6, 6, [2, 0, -1, 0, 0, 0, 0, 2, 0, -1, 0, 0,
+        -1, 0, 2, -1, 0, 0, 0, -1, -1, 2, -1, 0, 0, 0, 0,
+        -1, 2, -1, 0, 0, 0, 0, -1, 2])
+    assert c.cartan_matrix() == m
+    assert c.dimension() == 8
+    assert c.simple_root(6) == [0, 0, 0, -1, 1, 0, 0, 0]
+    assert c.roots() == 72
+    assert c.basis() == 78
+    diag = " "*8 + "2\n" + " "*8 + "0\n" + " "*8 + "|\n" + " "*8 + "|\n"
+    diag += "---".join("0" for i in range(1, 6))+"\n"
+    diag += "1   " + "   ".join(str(i) for i in range(3, 7))
+    assert c.dynkin_diagram() == diag
+    posroots = c.positive_roots()
+    assert posroots[8] == [1, 0, 0, 0, 1, 0, 0, 0]

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_F.py

@@ -0,0 +1,24 @@
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+from sympy.core.backend import S
+
+def test_type_F():
+    c = CartanType("F4")
+    m = Matrix(4, 4, [2, -1, 0, 0, -1, 2, -2, 0, 0, -1, 2, -1, 0, 0, -1, 2])
+    assert c.cartan_matrix() == m
+    assert c.dimension() == 4
+    assert c.simple_root(1) == [1, -1, 0, 0]
+    assert c.simple_root(2) == [0, 1, -1, 0]
+    assert c.simple_root(3) == [0, 0, 0, 1]
+    assert c.simple_root(4) == [-S.Half, -S.Half, -S.Half, -S.Half]
+    assert c.roots() == 48
+    assert c.basis() == 52
+    diag = "0---0=>=0---0\n" + "   ".join(str(i) for i in range(1, 5))
+    assert c.dynkin_diagram() == diag
+    assert c.positive_roots() == {1: [1, -1, 0, 0], 2: [1, 1, 0, 0], 3: [1, 0, -1, 0],
+            4: [1, 0, 1, 0], 5: [1, 0, 0, -1], 6: [1, 0, 0, 1], 7: [0, 1, -1, 0],
+            8: [0, 1, 1, 0], 9: [0, 1, 0, -1], 10: [0, 1, 0, 1], 11: [0, 0, 1, -1],
+            12: [0, 0, 1, 1], 13: [1, 0, 0, 0], 14: [0, 1, 0, 0], 15: [0, 0, 1, 0],
+            16: [0, 0, 0, 1], 17: [S.Half, S.Half, S.Half, S.Half], 18: [S.Half, -S.Half, S.Half, S.Half],
+            19: [S.Half, S.Half, -S.Half, S.Half], 20: [S.Half, S.Half, S.Half, -S.Half], 21: [S.Half, S.Half, -S.Half, -S.Half],
+            22: [S.Half, -S.Half, S.Half, -S.Half], 23: [S.Half, -S.Half, -S.Half, S.Half], 24: [S.Half, -S.Half, -S.Half, -S.Half]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_type_G.py

@@ -0,0 +1,16 @@
+# coding=utf-8
+from sympy.liealgebras.cartan_type import CartanType
+from sympy.matrices import Matrix
+
+def test_type_G():
+    c = CartanType("G2")
+    m = Matrix(2, 2, [2, -1, -3, 2])
+    assert c.cartan_matrix() == m
+    assert c.simple_root(2) == [1, -2, 1]
+    assert c.basis() == 14
+    assert c.roots() == 12
+    assert c.dimension() == 3
+    diag = "0≡<≡0\n1   2"
+    assert diag == c.dynkin_diagram()
+    assert c.positive_roots() == {1: [0, 1, -1], 2: [1, -2, 1], 3: [1, -1, 0],
+            4: [1, 0, 1], 5: [1, 1, -2], 6: [2, -1, -1]}

rl/Lib/site-packages/sympy/liealgebras/tests/test_weyl_group.py

@@ -0,0 +1,35 @@
+from sympy.liealgebras.weyl_group import WeylGroup
+from sympy.matrices import Matrix
+
+def test_weyl_group():
+    c = WeylGroup("A3")
+    assert c.matrix_form('r1*r2') == Matrix([[0, 0, 1, 0], [1, 0, 0, 0],
+        [0, 1, 0, 0], [0, 0, 0, 1]])
+    assert c.generators() == ['r1', 'r2', 'r3']
+    assert c.group_order() == 24.0
+    assert c.group_name() == "S4: the symmetric group acting on 4 elements."
+    assert c.coxeter_diagram() == "0---0---0\n1   2   3"
+    assert c.element_order('r1*r2*r3') == 4
+    assert c.element_order('r1*r3*r2*r3') == 3
+    d = WeylGroup("B5")
+    assert d.group_order() == 3840
+    assert d.element_order('r1*r2*r4*r5') == 12
+    assert d.matrix_form('r2*r3') ==  Matrix([[0, 0, 1, 0, 0], [1, 0, 0, 0, 0],
+        [0, 1, 0, 0, 0], [0, 0, 0, 1, 0], [0, 0, 0, 0, 1]])
+    assert d.element_order('r1*r2*r1*r3*r5') == 6
+    e = WeylGroup("D5")
+    assert e.element_order('r2*r3*r5') == 4
+    assert e.matrix_form('r2*r3*r5') == Matrix([[1, 0, 0, 0, 0], [0, 0, 0, 0, -1],
+        [0, 1, 0, 0, 0], [0, 0, 1, 0, 0], [0, 0, 0, -1, 0]])
+    f = WeylGroup("G2")
+    assert f.element_order('r1*r2*r1*r2') == 3
+    assert f.element_order('r2*r1*r1*r2') == 1
+
+    assert f.matrix_form('r1*r2*r1*r2') == Matrix([[0, 1, 0], [0, 0, 1], [1, 0, 0]])
+    g = WeylGroup("F4")
+    assert g.matrix_form('r2*r3') == Matrix([[1, 0, 0, 0], [0, 1, 0, 0],
+        [0, 0, 0, -1], [0, 0, 1, 0]])
+
+    assert g.element_order('r2*r3') == 4
+    h = WeylGroup("E6")
+    assert h.group_order() == 51840

rl/Lib/site-packages/sympy/liealgebras/type_a.py

@@ -0,0 +1,166 @@
+from sympy.liealgebras.cartan_type import Standard_Cartan
+from sympy.core.backend import eye
+
+
+class TypeA(Standard_Cartan):
+    """
+    This class contains the information about
+    the A series of simple Lie algebras.
+    ====
+    """
+
+    def __new__(cls, n):
+        if n < 1:
+            raise ValueError("n cannot be less than 1")
+        return Standard_Cartan.__new__(cls, "A", n)
+
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A4")
+        >>> c.dimension()
+        5
+        """
+        return self.n+1
+
+
+    def basic_root(self, i, j):
+        """
+        This is a method just to generate roots
+        with a 1 iin the ith position and a -1
+        in the jth position.
+
+        """
+
+        n = self.n
+        root = [0]*(n+1)
+        root[i] = 1
+        root[j] = -1
+        return root
+
+    def simple_root(self, i):
+        """
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        In A_n the ith simple root is the root which has a 1
+        in the ith position, a -1 in the (i+1)th position,
+        and zeroes elsewhere.
+
+        This method returns the ith simple root for the A series.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A4")
+        >>> c.simple_root(1)
+        [1, -1, 0, 0, 0]
+
+        """
+
+        return self.basic_root(i-1, i)
+
+    def positive_roots(self):
+        """
+        This method generates all the positive roots of
+        A_n.  This is half of all of the roots of A_n;
+        by multiplying all the positive roots by -1 we
+        get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+        """
+
+        n = self.n
+        posroots = {}
+        k = 0
+        for i in range(0, n):
+            for j in range(i+1, n+1):
+               k += 1
+               posroots[k] = self.basic_root(i, j)
+        return posroots
+
+    def highest_root(self):
+        """
+        Returns the highest weight root for A_n
+        """
+
+        return self.basic_root(0, self.n)
+
+    def roots(self):
+        """
+        Returns the total number of roots for A_n
+        """
+        n = self.n
+        return n*(n+1)
+
+    def cartan_matrix(self):
+        """
+        Returns the Cartan matrix for A_n.
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('A4')
+        >>> c.cartan_matrix()
+        Matrix([
+        [ 2, -1,  0,  0],
+        [-1,  2, -1,  0],
+        [ 0, -1,  2, -1],
+        [ 0,  0, -1,  2]])
+
+        """
+
+        n = self.n
+        m = 2 * eye(n)
+        i = 1
+        while i < n-1:
+            m[i, i+1] = -1
+            m[i, i-1] = -1
+            i += 1
+        m[0,1] = -1
+        m[n-1, n-2] = -1
+        return m
+
+    def basis(self):
+        """
+        Returns the number of independent generators of A_n
+        """
+        n = self.n
+        return n**2 - 1
+
+    def lie_algebra(self):
+        """
+        Returns the Lie algebra associated with A_n
+        """
+        n = self.n
+        return "su(" + str(n + 1) + ")"
+
+    def dynkin_diagram(self):
+        n = self.n
+        diag = "---".join("0" for i in range(1, n+1)) + "\n"
+        diag += "   ".join(str(i) for i in range(1, n+1))
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_b.py

@@ -0,0 +1,172 @@
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import eye
+
+class TypeB(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n < 2:
+            raise ValueError("n cannot be less than 2")
+        return Standard_Cartan.__new__(cls, "B", n)
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("B3")
+        >>> c.dimension()
+        3
+        """
+
+        return self.n
+
+    def basic_root(self, i, j):
+        """
+        This is a method just to generate roots
+        with a 1 iin the ith position and a -1
+        in the jth position.
+
+        """
+        root = [0]*self.n
+        root[i] = 1
+        root[j] = -1
+        return root
+
+    def simple_root(self, i):
+        """
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        In B_n the first n-1 simple roots are the same as the
+        roots in A_(n-1) (a 1 in the ith position, a -1 in
+        the (i+1)th position, and zeroes elsewhere).  The n-th
+        simple root is the root with a 1 in the nth position
+        and zeroes elsewhere.
+
+        This method returns the ith simple root for the B series.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("B3")
+        >>> c.simple_root(2)
+        [0, 1, -1]
+
+        """
+        n = self.n
+        if i < n:
+            return self.basic_root(i-1, i)
+        else:
+            root = [0]*self.n
+            root[n-1] = 1
+            return root
+
+    def positive_roots(self):
+        """
+        This method generates all the positive roots of
+        A_n.  This is half of all of the roots of B_n;
+        by multiplying all the positive roots by -1 we
+        get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+        """
+
+        n = self.n
+        posroots = {}
+        k = 0
+        for i in range(0, n-1):
+            for j in range(i+1, n):
+               k += 1
+               posroots[k] = self.basic_root(i, j)
+               k += 1
+               root = self.basic_root(i, j)
+               root[j] = 1
+               posroots[k] = root
+
+        for i in range(0, n):
+            k += 1
+            root = [0]*n
+            root[i] = 1
+            posroots[k] = root
+
+        return posroots
+
+    def roots(self):
+        """
+        Returns the total number of roots for B_n"
+        """
+
+        n = self.n
+        return 2*(n**2)
+
+    def cartan_matrix(self):
+        """
+        Returns the Cartan matrix for B_n.
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('B4')
+        >>> c.cartan_matrix()
+        Matrix([
+        [ 2, -1,  0,  0],
+        [-1,  2, -1,  0],
+        [ 0, -1,  2, -2],
+        [ 0,  0, -1,  2]])
+
+        """
+
+        n = self.n
+        m = 2* eye(n)
+        i = 1
+        while i < n-1:
+            m[i, i+1] = -1
+            m[i, i-1] = -1
+            i += 1
+        m[0, 1] = -1
+        m[n-2, n-1] = -2
+        m[n-1, n-2] = -1
+        return m
+
+    def basis(self):
+        """
+        Returns the number of independent generators of B_n
+        """
+
+        n = self.n
+        return (n**2 - n)/2
+
+    def lie_algebra(self):
+        """
+        Returns the Lie algebra associated with B_n
+        """
+
+        n = self.n
+        return "so(" + str(2*n) + ")"
+
+    def dynkin_diagram(self):
+        n = self.n
+        diag = "---".join("0" for i in range(1, n)) + "=>=0\n"
+        diag += "   ".join(str(i) for i in range(1, n+1))
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_c.py

@@ -0,0 +1,171 @@
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import eye
+
+class TypeC(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n < 3:
+            raise ValueError("n cannot be less than 3")
+        return Standard_Cartan.__new__(cls, "C", n)
+
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("C3")
+        >>> c.dimension()
+        3
+        """
+        n = self.n
+        return n
+
+    def basic_root(self, i, j):
+        """Generate roots with 1 in ith position and a -1 in jth position
+        """
+        n = self.n
+        root = [0]*n
+        root[i] = 1
+        root[j] = -1
+        return root
+
+    def simple_root(self, i):
+        """The ith simple root for the C series
+
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        In C_n, the first n-1 simple roots are the same as
+        the roots in A_(n-1) (a 1 in the ith position, a -1
+        in the (i+1)th position, and zeroes elsewhere).  The
+        nth simple root is the root in which there is a 2 in
+        the nth position and zeroes elsewhere.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("C3")
+        >>> c.simple_root(2)
+        [0, 1, -1]
+
+        """
+
+        n = self.n
+        if i < n:
+            return self.basic_root(i-1,i)
+        else:
+            root = [0]*self.n
+            root[n-1] = 2
+            return root
+
+
+    def positive_roots(self):
+        """Generates all the positive roots of A_n
+
+        This is half of all of the roots of C_n; by multiplying all the
+        positive roots by -1 we get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+
+        """
+
+        n = self.n
+        posroots = {}
+        k = 0
+        for i in range(0, n-1):
+            for j in range(i+1, n):
+               k += 1
+               posroots[k] = self.basic_root(i, j)
+               k += 1
+               root = self.basic_root(i, j)
+               root[j] = 1
+               posroots[k] = root
+
+        for i in range(0, n):
+            k += 1
+            root = [0]*n
+            root[i] = 2
+            posroots[k] = root
+
+        return posroots
+
+    def roots(self):
+        """
+        Returns the total number of roots for C_n"
+        """
+
+        n = self.n
+        return 2*(n**2)
+
+    def cartan_matrix(self):
+        """The Cartan matrix for C_n
+
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('C4')
+        >>> c.cartan_matrix()
+        Matrix([
+        [ 2, -1,  0,  0],
+        [-1,  2, -1,  0],
+        [ 0, -1,  2, -1],
+        [ 0,  0, -2,  2]])
+
+        """
+
+        n = self.n
+        m = 2 * eye(n)
+        i = 1
+        while i < n-1:
+           m[i, i+1] = -1
+           m[i, i-1] = -1
+           i += 1
+        m[0,1] = -1
+        m[n-1, n-2] = -2
+        return m
+
+
+    def basis(self):
+        """
+        Returns the number of independent generators of C_n
+        """
+
+        n = self.n
+        return n*(2*n + 1)
+
+    def lie_algebra(self):
+        """
+        Returns the Lie algebra associated with C_n"
+        """
+
+        n = self.n
+        return "sp(" + str(2*n) + ")"
+
+    def dynkin_diagram(self):
+        n = self.n
+        diag = "---".join("0" for i in range(1, n)) + "=<=0\n"
+        diag += "   ".join(str(i) for i in range(1, n+1))
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_d.py

@@ -0,0 +1,175 @@
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import eye
+
+class TypeD(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n < 3:
+            raise ValueError("n cannot be less than 3")
+        return Standard_Cartan.__new__(cls, "D", n)
+
+
+    def dimension(self):
+        """Dmension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("D4")
+        >>> c.dimension()
+        4
+        """
+
+        return self.n
+
+    def basic_root(self, i, j):
+        """
+        This is a method just to generate roots
+        with a 1 iin the ith position and a -1
+        in the jth position.
+
+        """
+
+        n = self.n
+        root = [0]*n
+        root[i] = 1
+        root[j] = -1
+        return root
+
+    def simple_root(self, i):
+        """
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        In D_n, the first n-1 simple roots are the same as
+        the roots in A_(n-1) (a 1 in the ith position, a -1
+        in the (i+1)th position, and zeroes elsewhere).
+        The nth simple root is the root in which there 1s in
+        the nth and (n-1)th positions, and zeroes elsewhere.
+
+        This method returns the ith simple root for the D series.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("D4")
+        >>> c.simple_root(2)
+        [0, 1, -1, 0]
+
+        """
+
+        n = self.n
+        if i < n:
+            return self.basic_root(i-1, i)
+        else:
+            root = [0]*n
+            root[n-2] = 1
+            root[n-1] = 1
+            return root
+
+
+    def positive_roots(self):
+        """
+        This method generates all the positive roots of
+        A_n.  This is half of all of the roots of D_n
+        by multiplying all the positive roots by -1 we
+        get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+        """
+
+        n = self.n
+        posroots = {}
+        k = 0
+        for i in range(0, n-1):
+            for j in range(i+1, n):
+               k += 1
+               posroots[k] = self.basic_root(i, j)
+               k += 1
+               root = self.basic_root(i, j)
+               root[j] = 1
+               posroots[k] = root
+        return posroots
+
+    def roots(self):
+        """
+        Returns the total number of roots for D_n"
+        """
+
+        n = self.n
+        return 2*n*(n-1)
+
+    def cartan_matrix(self):
+        """
+        Returns the Cartan matrix for D_n.
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('D4')
+        >>> c.cartan_matrix()
+            Matrix([
+            [ 2, -1,  0,  0],
+            [-1,  2, -1, -1],
+            [ 0, -1,  2,  0],
+            [ 0, -1,  0,  2]])
+
+        """
+
+        n = self.n
+        m = 2*eye(n)
+        i = 1
+        while i < n-2:
+           m[i,i+1] = -1
+           m[i,i-1] = -1
+           i += 1
+        m[n-2, n-3] = -1
+        m[n-3, n-1] = -1
+        m[n-1, n-3] = -1
+        m[0, 1] = -1
+        return m
+
+    def basis(self):
+        """
+        Returns the number of independent generators of D_n
+        """
+        n = self.n
+        return n*(n-1)/2
+
+    def lie_algebra(self):
+        """
+        Returns the Lie algebra associated with D_n"
+        """
+
+        n = self.n
+        return "so(" + str(2*n) + ")"
+
+    def dynkin_diagram(self):
+        n = self.n
+        diag = " "*4*(n-3) + str(n-1) + "\n"
+        diag += " "*4*(n-3) + "0\n"
+        diag += " "*4*(n-3) +"|\n"
+        diag += " "*4*(n-3) + "|\n"
+        diag += "---".join("0" for i in range(1,n)) + "\n"
+        diag += "   ".join(str(i) for i in range(1, n-1)) + "   "+str(n)
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_e.py

@@ -0,0 +1,287 @@
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import eye, Rational
+
+
+class TypeE(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n < 6 or n > 8:
+            raise ValueError("Invalid value of n")
+        return Standard_Cartan.__new__(cls, "E", n)
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("E6")
+        >>> c.dimension()
+        8
+        """
+
+        return 8
+
+    def basic_root(self, i, j):
+        """
+        This is a method just to generate roots
+        with a -1 in the ith position and a 1
+        in the jth position.
+
+        """
+
+        root = [0]*8
+        root[i] = -1
+        root[j] = 1
+        return root
+
+    def simple_root(self, i):
+        """
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        This method returns the ith simple root for E_n.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("E6")
+        >>> c.simple_root(2)
+        [1, 1, 0, 0, 0, 0, 0, 0]
+        """
+        n = self.n
+        if i == 1:
+            root = [-0.5]*8
+            root[0] = 0.5
+            root[7] = 0.5
+            return root
+        elif i == 2:
+            root = [0]*8
+            root[1] = 1
+            root[0] = 1
+            return root
+        else:
+            if i in (7, 8) and n == 6:
+                raise ValueError("E6 only has six simple roots!")
+            if i == 8 and n == 7:
+                raise ValueError("E7 has only 7 simple roots!")
+
+            return self.basic_root(i - 3, i - 2)
+
+    def positive_roots(self):
+        """
+        This method generates all the positive roots of
+        A_n.  This is half of all of the roots of E_n;
+        by multiplying all the positive roots by -1 we
+        get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+        """
+        n = self.n
+        if n == 6:
+            posroots = {}
+            k = 0
+            for i in range(n-1):
+                for j in range(i+1, n-1):
+                    k += 1
+                    root = self.basic_root(i, j)
+                    posroots[k] = root
+                    k += 1
+                    root = self.basic_root(i, j)
+                    root[i] = 1
+                    posroots[k] = root
+
+            root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
+                    Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
+            for a in range(0, 2):
+                for b in range(0, 2):
+                    for c in range(0, 2):
+                        for d in range(0, 2):
+                            for e in range(0, 2):
+                                if (a + b + c + d + e)%2 == 0:
+                                    k += 1
+                                    if a == 1:
+                                        root[0] = Rational(-1, 2)
+                                    if b == 1:
+                                        root[1] = Rational(-1, 2)
+                                    if c == 1:
+                                        root[2] = Rational(-1, 2)
+                                    if d == 1:
+                                        root[3] = Rational(-1, 2)
+                                    if e == 1:
+                                        root[4] = Rational(-1, 2)
+                                    posroots[k] = root
+
+            return posroots
+        if n == 7:
+            posroots = {}
+            k = 0
+            for i in range(n-1):
+                for j in range(i+1, n-1):
+                    k += 1
+                    root = self.basic_root(i, j)
+                    posroots[k] = root
+                    k += 1
+                    root = self.basic_root(i, j)
+                    root[i] = 1
+                    posroots[k] = root
+
+            k += 1
+            posroots[k] = [0, 0, 0, 0, 0, 1, 1, 0]
+            root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
+                    Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
+            for a in range(0, 2):
+                for b in range(0, 2):
+                    for c in range(0, 2):
+                        for d in range(0, 2):
+                            for e in range(0, 2):
+                                for f in range(0, 2):
+                                    if (a + b + c + d + e + f)%2 == 0:
+                                        k += 1
+                                        if a == 1:
+                                            root[0] = Rational(-1, 2)
+                                        if b == 1:
+                                            root[1] = Rational(-1, 2)
+                                        if c == 1:
+                                            root[2] = Rational(-1, 2)
+                                        if d == 1:
+                                            root[3] = Rational(-1, 2)
+                                        if e == 1:
+                                            root[4] = Rational(-1, 2)
+                                        if f == 1:
+                                            root[5] = Rational(1, 2)
+                                        posroots[k] = root
+
+            return posroots
+        if n == 8:
+            posroots = {}
+            k = 0
+            for i in range(n):
+                for j in range(i+1, n):
+                    k += 1
+                    root = self.basic_root(i, j)
+                    posroots[k] = root
+                    k += 1
+                    root = self.basic_root(i, j)
+                    root[i] = 1
+                    posroots[k] = root
+
+            root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
+                    Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
+            for a in range(0, 2):
+                for b in range(0, 2):
+                    for c in range(0, 2):
+                        for d in range(0, 2):
+                            for e in range(0, 2):
+                                for f in range(0, 2):
+                                    for g in range(0, 2):
+                                        if (a + b + c + d + e + f + g)%2 == 0:
+                                            k += 1
+                                            if a == 1:
+                                                root[0] = Rational(-1, 2)
+                                            if b == 1:
+                                                root[1] = Rational(-1, 2)
+                                            if c == 1:
+                                                root[2] = Rational(-1, 2)
+                                            if d == 1:
+                                                root[3] = Rational(-1, 2)
+                                            if e == 1:
+                                                root[4] = Rational(-1, 2)
+                                            if f == 1:
+                                                root[5] = Rational(1, 2)
+                                            if g == 1:
+                                                root[6] = Rational(1, 2)
+                                            posroots[k] = root
+
+            return posroots
+
+
+
+    def roots(self):
+        """
+        Returns the total number of roots of E_n
+        """
+
+        n = self.n
+        if n == 6:
+            return 72
+        if n == 7:
+            return 126
+        if n == 8:
+            return 240
+
+
+    def cartan_matrix(self):
+        """
+        Returns the Cartan matrix for G_2
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('A4')
+        >>> c.cartan_matrix()
+        Matrix([
+        [ 2, -1,  0,  0],
+        [-1,  2, -1,  0],
+        [ 0, -1,  2, -1],
+        [ 0,  0, -1,  2]])
+
+
+        """
+
+        n = self.n
+        m = 2*eye(n)
+        i = 3
+        while i < n-1:
+            m[i, i+1] = -1
+            m[i, i-1] = -1
+            i += 1
+        m[0, 2] = m[2, 0] = -1
+        m[1, 3] = m[3, 1] = -1
+        m[2, 3] = -1
+        m[n-1, n-2] = -1
+        return m
+
+
+    def basis(self):
+        """
+        Returns the number of independent generators of E_n
+        """
+
+        n = self.n
+        if n == 6:
+            return 78
+        if n == 7:
+            return 133
+        if n == 8:
+            return 248
+
+    def dynkin_diagram(self):
+        n = self.n
+        diag = " "*8 + str(2) + "\n"
+        diag += " "*8 + "0\n"
+        diag += " "*8 + "|\n"
+        diag += " "*8 + "|\n"
+        diag += "---".join("0" for i in range(1, n)) + "\n"
+        diag += "1   " + "   ".join(str(i) for i in range(3, n+1))
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_f.py

@@ -0,0 +1,162 @@
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import Matrix, Rational
+
+
+class TypeF(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n != 4:
+            raise ValueError("n should be 4")
+        return Standard_Cartan.__new__(cls, "F", 4)
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("F4")
+        >>> c.dimension()
+        4
+        """
+
+        return 4
+
+
+    def basic_root(self, i, j):
+        """Generate roots with 1 in ith position and -1 in jth position
+
+        """
+
+        n = self.n
+        root = [0]*n
+        root[i] = 1
+        root[j] = -1
+        return root
+
+    def simple_root(self, i):
+        """The ith simple root of F_4
+
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("F4")
+        >>> c.simple_root(3)
+        [0, 0, 0, 1]
+
+        """
+
+        if i < 3:
+            return self.basic_root(i-1, i)
+        if i == 3:
+            root = [0]*4
+            root[3] = 1
+            return root
+        if i == 4:
+            root = [Rational(-1, 2)]*4
+            return root
+
+    def positive_roots(self):
+        """Generate all the positive roots of A_n
+
+        This is half of all of the roots of F_4; by multiplying all the
+        positive roots by -1 we get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+
+        """
+
+        n = self.n
+        posroots = {}
+        k = 0
+        for i in range(0, n-1):
+            for j in range(i+1, n):
+               k += 1
+               posroots[k] = self.basic_root(i, j)
+               k += 1
+               root = self.basic_root(i, j)
+               root[j] = 1
+               posroots[k] = root
+
+        for i in range(0, n):
+            k += 1
+            root = [0]*n
+            root[i] = 1
+            posroots[k] = root
+
+        k += 1
+        root = [Rational(1, 2)]*n
+        posroots[k] = root
+        for i in range(1, 4):
+            k += 1
+            root = [Rational(1, 2)]*n
+            root[i] = Rational(-1, 2)
+            posroots[k] = root
+
+        posroots[k+1] = [Rational(1, 2), Rational(1, 2), Rational(-1, 2), Rational(-1, 2)]
+        posroots[k+2] = [Rational(1, 2), Rational(-1, 2), Rational(1, 2), Rational(-1, 2)]
+        posroots[k+3] = [Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
+        posroots[k+4] = [Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(-1, 2)]
+
+        return posroots
+
+
+    def roots(self):
+        """
+        Returns the total number of roots for F_4
+        """
+        return 48
+
+    def cartan_matrix(self):
+        """The Cartan matrix for F_4
+
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType('A4')
+        >>> c.cartan_matrix()
+        Matrix([
+        [ 2, -1,  0,  0],
+        [-1,  2, -1,  0],
+        [ 0, -1,  2, -1],
+        [ 0,  0, -1,  2]])
+        """
+
+        m = Matrix( 4, 4, [2, -1, 0, 0, -1, 2, -2, 0, 0,
+            -1, 2, -1, 0, 0, -1, 2])
+        return m
+
+    def basis(self):
+        """
+        Returns the number of independent generators of F_4
+        """
+        return 52
+
+    def dynkin_diagram(self):
+        diag = "0---0=>=0---0\n"
+        diag += "   ".join(str(i) for i in range(1, 5))
+        return diag

rl/Lib/site-packages/sympy/liealgebras/type_g.py

@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*-
+
+from .cartan_type import Standard_Cartan
+from sympy.core.backend import Matrix
+
+class TypeG(Standard_Cartan):
+
+    def __new__(cls, n):
+        if n != 2:
+            raise ValueError("n should be 2")
+        return Standard_Cartan.__new__(cls, "G", 2)
+
+
+    def dimension(self):
+        """Dimension of the vector space V underlying the Lie algebra
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("G2")
+        >>> c.dimension()
+        3
+        """
+        return 3
+
+    def simple_root(self, i):
+        """The ith simple root of G_2
+
+        Every lie algebra has a unique root system.
+        Given a root system Q, there is a subset of the
+        roots such that an element of Q is called a
+        simple root if it cannot be written as the sum
+        of two elements in Q.  If we let D denote the
+        set of simple roots, then it is clear that every
+        element of Q can be written as a linear combination
+        of elements of D with all coefficients non-negative.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("G2")
+        >>> c.simple_root(1)
+        [0, 1, -1]
+
+        """
+        if i == 1:
+            return [0, 1, -1]
+        else:
+            return [1, -2, 1]
+
+    def positive_roots(self):
+        """Generate all the positive roots of A_n
+
+        This is half of all of the roots of A_n; by multiplying all the
+        positive roots by -1 we get the negative roots.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("A3")
+        >>> c.positive_roots()
+        {1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
+                5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
+
+        """
+
+        roots = {1: [0, 1, -1], 2: [1, -2, 1], 3: [1, -1, 0], 4: [1, 0, 1],
+                5: [1, 1, -2], 6: [2, -1, -1]}
+        return roots
+
+    def roots(self):
+        """
+        Returns the total number of roots of G_2"
+        """
+        return 12
+
+    def cartan_matrix(self):
+        """The Cartan matrix for G_2
+
+        The Cartan matrix matrix for a Lie algebra is
+        generated by assigning an ordering to the simple
+        roots, (alpha[1], ...., alpha[l]).  Then the ijth
+        entry of the Cartan matrix is (<alpha[i],alpha[j]>).
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.cartan_type import CartanType
+        >>> c = CartanType("G2")
+        >>> c.cartan_matrix()
+        Matrix([
+            [ 2, -1],
+            [-3,  2]])
+
+        """
+
+        m = Matrix( 2, 2, [2, -1, -3, 2])
+        return m
+
+    def basis(self):
+        """
+        Returns the number of independent generators of G_2
+        """
+        return 14
+
+    def dynkin_diagram(self):
+        diag = "0≡<≡0\n1   2"
+        return diag

rl/Lib/site-packages/sympy/liealgebras/weyl_group.py

@@ -0,0 +1,403 @@
+# -*- coding: utf-8 -*-
+
+from .cartan_type import CartanType
+from mpmath import fac
+from sympy.core.backend import Matrix, eye, Rational, igcd
+from sympy.core.basic import Atom
+
+class WeylGroup(Atom):
+
+    """
+    For each semisimple Lie group, we have a Weyl group.  It is a subgroup of
+    the isometry group of the root system.  Specifically, it's the subgroup
+    that is generated by reflections through the hyperplanes orthogonal to
+    the roots.  Therefore, Weyl groups are reflection groups, and so a Weyl
+    group is a finite Coxeter group.
+
+    """
+
+    def __new__(cls, cartantype):
+        obj = Atom.__new__(cls)
+        obj.cartan_type = CartanType(cartantype)
+        return obj
+
+    def generators(self):
+        """
+        This method creates the generating reflections of the Weyl group for
+        a given Lie algebra.  For a Lie algebra of rank n, there are n
+        different generating reflections.  This function returns them as
+        a list.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.weyl_group import WeylGroup
+        >>> c = WeylGroup("F4")
+        >>> c.generators()
+        ['r1', 'r2', 'r3', 'r4']
+        """
+        n = self.cartan_type.rank()
+        generators = []
+        for i in range(1, n+1):
+            reflection = "r"+str(i)
+            generators.append(reflection)
+        return generators
+
+    def group_order(self):
+        """
+        This method returns the order of the Weyl group.
+        For types A, B, C, D, and E the order depends on
+        the rank of the Lie algebra.  For types F and G,
+        the order is fixed.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.weyl_group import WeylGroup
+        >>> c = WeylGroup("D4")
+        >>> c.group_order()
+        192.0
+        """
+        n = self.cartan_type.rank()
+        if self.cartan_type.series == "A":
+            return fac(n+1)
+
+        if self.cartan_type.series in ("B", "C"):
+            return fac(n)*(2**n)
+
+        if self.cartan_type.series == "D":
+            return fac(n)*(2**(n-1))
+
+        if self.cartan_type.series == "E":
+            if n == 6:
+                return 51840
+            if n == 7:
+                return 2903040
+            if n == 8:
+                return 696729600
+        if self.cartan_type.series == "F":
+            return 1152
+
+        if self.cartan_type.series == "G":
+            return 12
+
+    def group_name(self):
+        """
+        This method returns some general information about the Weyl group for
+        a given Lie algebra.  It returns the name of the group and the elements
+        it acts on, if relevant.
+        """
+        n = self.cartan_type.rank()
+        if self.cartan_type.series == "A":
+            return "S"+str(n+1) + ": the symmetric group acting on " + str(n+1) + " elements."
+
+        if self.cartan_type.series in ("B", "C"):
+            return "The hyperoctahedral group acting on " + str(2*n) + " elements."
+
+        if self.cartan_type.series == "D":
+            return "The symmetry group of the " + str(n) + "-dimensional demihypercube."
+
+        if self.cartan_type.series == "E":
+            if n == 6:
+                return "The symmetry group of the 6-polytope."
+
+            if n == 7:
+                return "The symmetry group of the 7-polytope."
+
+            if n == 8:
+                return "The symmetry group of the 8-polytope."
+
+        if self.cartan_type.series == "F":
+            return "The symmetry group of the 24-cell, or icositetrachoron."
+
+        if self.cartan_type.series == "G":
+            return "D6, the dihedral group of order 12, and symmetry group of the hexagon."
+
+    def element_order(self, weylelt):
+        """
+        This method returns the order of a given Weyl group element, which should
+        be specified by the user in the form of products of the generating
+        reflections, i.e. of the form r1*r2 etc.
+
+        For types A-F, this method current works by taking the matrix form of
+        the specified element, and then finding what power of the matrix is the
+        identity.  It then returns this power.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.weyl_group import WeylGroup
+        >>> b = WeylGroup("B4")
+        >>> b.element_order('r1*r4*r2')
+        4
+        """
+        n = self.cartan_type.rank()
+        if self.cartan_type.series == "A":
+            a = self.matrix_form(weylelt)
+            order = 1
+            while a != eye(n+1):
+                a *= self.matrix_form(weylelt)
+                order += 1
+            return order
+
+        if self.cartan_type.series == "D":
+            a = self.matrix_form(weylelt)
+            order = 1
+            while a != eye(n):
+                a *= self.matrix_form(weylelt)
+                order += 1
+            return order
+
+        if self.cartan_type.series == "E":
+            a = self.matrix_form(weylelt)
+            order = 1
+            while a != eye(8):
+                a *= self.matrix_form(weylelt)
+                order += 1
+            return order
+
+        if self.cartan_type.series == "G":
+            elts = list(weylelt)
+            reflections = elts[1::3]
+            m = self.delete_doubles(reflections)
+            while self.delete_doubles(m) != m:
+                m = self.delete_doubles(m)
+                reflections = m
+            if len(reflections) % 2 == 1:
+                return 2
+
+            elif len(reflections) == 0:
+                return 1
+
+            else:
+                if len(reflections) == 1:
+                    return 2
+                else:
+                    m = len(reflections) // 2
+                    lcm = (6 * m)/ igcd(m, 6)
+                order = lcm / m
+                return order
+
+
+        if self.cartan_type.series == 'F':
+            a = self.matrix_form(weylelt)
+            order = 1
+            while a != eye(4):
+                a *= self.matrix_form(weylelt)
+                order += 1
+            return order
+
+
+        if self.cartan_type.series in ("B", "C"):
+            a = self.matrix_form(weylelt)
+            order = 1
+            while a != eye(n):
+                a *= self.matrix_form(weylelt)
+                order += 1
+            return order
+
+    def delete_doubles(self, reflections):
+        """
+        This is a helper method for determining the order of an element in the
+        Weyl group of G2.  It takes a Weyl element and if repeated simple reflections
+        in it, it deletes them.
+        """
+        counter = 0
+        copy = list(reflections)
+        for elt in copy:
+            if counter < len(copy)-1:
+                if copy[counter + 1] == elt:
+                    del copy[counter]
+                    del copy[counter]
+            counter += 1
+
+
+        return copy
+
+
+    def matrix_form(self, weylelt):
+        """
+        This method takes input from the user in the form of products of the
+        generating reflections, and returns the matrix corresponding to the
+        element of the Weyl group.  Since each element of the Weyl group is
+        a reflection of some type, there is a corresponding matrix representation.
+        This method uses the standard representation for all the generating
+        reflections.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.weyl_group import WeylGroup
+        >>> f = WeylGroup("F4")
+        >>> f.matrix_form('r2*r3')
+        Matrix([
+        [1, 0, 0,  0],
+        [0, 1, 0,  0],
+        [0, 0, 0, -1],
+        [0, 0, 1,  0]])
+
+        """
+        elts = list(weylelt)
+        reflections = elts[1::3]
+        n = self.cartan_type.rank()
+        if self.cartan_type.series == 'A':
+            matrixform = eye(n+1)
+            for elt in reflections:
+                a = int(elt)
+                mat = eye(n+1)
+                mat[a-1, a-1] = 0
+                mat[a-1, a] = 1
+                mat[a, a-1] = 1
+                mat[a, a] = 0
+                matrixform *= mat
+            return matrixform
+
+        if self.cartan_type.series == 'D':
+            matrixform = eye(n)
+            for elt in reflections:
+                a = int(elt)
+                mat = eye(n)
+                if a < n:
+                    mat[a-1, a-1] = 0
+                    mat[a-1, a] = 1
+                    mat[a, a-1] = 1
+                    mat[a, a] = 0
+                    matrixform *= mat
+                else:
+                    mat[n-2, n-1] = -1
+                    mat[n-2, n-2] = 0
+                    mat[n-1, n-2] = -1
+                    mat[n-1, n-1] = 0
+                    matrixform *= mat
+            return matrixform
+
+        if self.cartan_type.series == 'G':
+            matrixform = eye(3)
+            for elt in reflections:
+                a = int(elt)
+                if a == 1:
+                    gen1 = Matrix([[1, 0, 0], [0, 0, 1], [0, 1, 0]])
+                    matrixform *= gen1
+                else:
+                    gen2 = Matrix([[Rational(2, 3), Rational(2, 3), Rational(-1, 3)],
+                                   [Rational(2, 3), Rational(-1, 3), Rational(2, 3)],
+                                   [Rational(-1, 3), Rational(2, 3), Rational(2, 3)]])
+                    matrixform *= gen2
+            return matrixform
+
+        if self.cartan_type.series == 'F':
+            matrixform = eye(4)
+            for elt in reflections:
+                a = int(elt)
+                if a == 1:
+                    mat = Matrix([[1, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 0], [0, 0, 0, 1]])
+                    matrixform *= mat
+                elif a == 2:
+                    mat = Matrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 1], [0, 0, 1, 0]])
+                    matrixform *= mat
+                elif a == 3:
+                    mat = Matrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, -1]])
+                    matrixform *= mat
+                else:
+
+                    mat = Matrix([[Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2)],
+                        [Rational(1, 2), Rational(1, 2), Rational(-1, 2), Rational(-1, 2)],
+                        [Rational(1, 2), Rational(-1, 2), Rational(1, 2), Rational(-1, 2)],
+                        [Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]])
+                    matrixform *= mat
+            return matrixform
+
+        if self.cartan_type.series == 'E':
+            matrixform = eye(8)
+            for elt in reflections:
+                a = int(elt)
+                if a == 1:
+                    mat = Matrix([[Rational(3, 4), Rational(1, 4), Rational(1, 4), Rational(1, 4),
+                        Rational(1, 4), Rational(1, 4), Rational(1, 4), Rational(-1, 4)],
+                        [Rational(1, 4), Rational(3, 4), Rational(-1, 4), Rational(-1, 4),
+                            Rational(-1, 4), Rational(-1, 4), Rational(1, 4), Rational(-1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(3, 4), Rational(-1, 4),
+                        Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(3, 4),
+                        Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
+                        Rational(3, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
+                        Rational(-1, 4), Rational(3, 4), Rational(-1, 4), Rational(1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
+                        Rational(-1, 4), Rational(-1, 4), Rational(-3, 4), Rational(1, 4)],
+                        [Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
+                        Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(3, 4)]])
+                    matrixform *= mat
+                elif a == 2:
+                    mat = eye(8)
+                    mat[0, 0] = 0
+                    mat[0, 1] = -1
+                    mat[1, 0] = -1
+                    mat[1, 1] = 0
+                    matrixform *= mat
+                else:
+                    mat = eye(8)
+                    mat[a-3, a-3] = 0
+                    mat[a-3, a-2] = 1
+                    mat[a-2, a-3] = 1
+                    mat[a-2, a-2] = 0
+                    matrixform *= mat
+            return matrixform
+
+
+        if self.cartan_type.series in ("B", "C"):
+            matrixform = eye(n)
+            for elt in reflections:
+                a = int(elt)
+                mat = eye(n)
+                if a == 1:
+                    mat[0, 0] = -1
+                    matrixform *= mat
+                else:
+                    mat[a - 2, a - 2] = 0
+                    mat[a-2, a-1] = 1
+                    mat[a - 1, a - 2] = 1
+                    mat[a -1, a - 1] = 0
+                    matrixform *= mat
+            return matrixform
+
+
+
+    def coxeter_diagram(self):
+        """
+        This method returns the Coxeter diagram corresponding to a Weyl group.
+        The Coxeter diagram can be obtained from a Lie algebra's Dynkin diagram
+        by deleting all arrows; the Coxeter diagram is the undirected graph.
+        The vertices of the Coxeter diagram represent the generating reflections
+        of the Weyl group, $s_i$.  An edge is drawn between $s_i$ and $s_j$ if the order
+        $m(i, j)$ of $s_is_j$ is greater than two.  If there is one edge, the order
+        $m(i, j)$ is 3.  If there are two edges, the order $m(i, j)$ is 4, and if there
+        are three edges, the order $m(i, j)$ is 6.
+
+        Examples
+        ========
+
+        >>> from sympy.liealgebras.weyl_group import WeylGroup
+        >>> c = WeylGroup("B3")
+        >>> print(c.coxeter_diagram())
+        0---0===0
+        1   2   3
+        """
+        n = self.cartan_type.rank()
+        if self.cartan_type.series in ("A", "D", "E"):
+            return self.cartan_type.dynkin_diagram()
+
+        if self.cartan_type.series in ("B", "C"):
+            diag = "---".join("0" for i in range(1, n)) + "===0\n"
+            diag += "   ".join(str(i) for i in range(1, n+1))
+            return diag
+
+        if self.cartan_type.series == "F":
+            diag = "0---0===0---0\n"
+            diag += "   ".join(str(i) for i in range(1, 5))
+            return diag
+
+        if self.cartan_type.series == "G":
+            diag = "0≡≡≡0\n1   2"
+            return diag