def test_MatMul_postprocessor():
z = zeros(2)
z1 = ZeroMatrix(2, 2)
assert Mul(0, z) == Mul(z, 0) in [z, z1]
M = Matrix([[1, 2], [3, 4]])
Mx = Matrix([[x, 2*x], [3*x, 4*x]])
assert Mul(x, M) == Mul(M, x) == Mx
A = MatrixSymbol("A", 2, 2)
assert Mul(A, M) == MatMul(A, M)
assert Mul(M, A) == MatMul(M, A)
# Scalars should be absorbed into constant matrices
a = Mul(x, M, A)
b = Mul(M, x, A)
c = Mul(M, A, x)
assert a == b == c == MatMul(Mx, A)
a = Mul(x, A, M)
b = Mul(A, x, M)
c = Mul(A, M, x)
assert a == b == c == MatMul(A, Mx)
assert Mul(M, M) == M**2
assert Mul(A, M, M) == MatMul(A, M**2)
assert Mul(M, M, A) == MatMul(M**2, A)
assert Mul(M, A, M) == MatMul(M, A, M)
assert Mul(A, x, M, M, x) == MatMul(A, Mx**2)
def test_invariants():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
X = MatrixSymbol('X', n, n)
objs = [Identity(n), ZeroMatrix(m, n), A, MatMul(A, B), MatAdd(A, A),
Transpose(A), Adjoint(A), Inverse(X), MatPow(X, 2), MatPow(X, -1),
MatPow(X, 0)]
for obj in objs:
assert obj == obj.__class__(*obj.args)
def test_generic_identity():
I = GenericIdentity()
A = MatrixSymbol("A", n, n)
assert I == I
assert I != A
assert A != I
assert I.is_Identity
assert I**-1 == I
raises(TypeError, lambda: I.shape)
raises(TypeError, lambda: I.rows)
raises(TypeError, lambda: I.cols)
assert MatMul() == I
assert MatMul(I, A) == MatMul(A)
# Make sure it is hashable
hash(I)
def test_MatMul():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
assert (2 * A * B).shape == (n, l)
assert (A * 0 * B) == ZeroMatrix(n, l)
raises(ShapeError, lambda: B * A)
assert (2 * A).shape == A.shape
assert MatMul(A, ZeroMatrix(m, m), B) == ZeroMatrix(n, l)
assert MatMul(C * Identity(n) * C.I) == Identity(n)
assert B / 2 == S.Half * B
raises(NotImplementedError, lambda: 2 / B)
A = MatrixSymbol('A', n, n)
B = MatrixSymbol('B', n, n)
assert MatMul(Identity(n), (A + B)).is_MatAdd
def test_subs():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', m, l)
assert A.subs(n, m).shape == (m, m)
assert (A * B).subs(B, C) == A * C
assert (A * B).subs(l, n).is_square
A = SparseMatrix([[1, 2], [3, 4]])
B = Matrix([[1, 2], [3, 4]])
C, D = MatrixSymbol('C', 2, 2), MatrixSymbol('D', 2, 2)
assert (C * D).subs({C: A, D: B}) == MatMul(A, B)
def test_MatMul():
n, m, l = symbols('n m l', integer=True)
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
assert (2 * A * B).shape == (n, l)
assert (A * 0 * B) == ZeroMatrix(n, l)
raises(ShapeError, "B*A")
assert (2 * A).shape == A.shape
assert MatMul(A, ZeroMatrix(m, m), B) == ZeroMatrix(n, l)
assert MatMul(C * Identity(n) * C.I) == Identity(n)
assert B / 2 == S.Half * B
raises(NotImplementedError, "2/B")
A = MatrixSymbol('A', n, n)
B = MatrixSymbol('B', n, n)
assert MatMul(Identity(n), (A + B)).is_Add
def test_matexpr_subs():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', m, l)
assert A.subs(n, m).shape == (m, m)
assert (A * B).subs(B, C) == A * C
assert (A * B).subs(l, n).is_square
W = MatrixSymbol("W", 3, 3)
X = MatrixSymbol("X", 2, 2)
Y = MatrixSymbol("Y", 1, 2)
Z = MatrixSymbol("Z", n, 2)
# no restrictions on Symbol replacement
assert X.subs(X, Y) == Y
# it might be better to just change the name
y = Str('y')
assert X.subs(Str("X"), y).args == (y, 2, 2)
# it's ok to introduce a wider matrix
assert X[1, 1].subs(X, W) == W[1, 1]
# but for a given MatrixExpression, only change
# name if indexing on the new shape is valid.
# Here, X is 2,2; Y is 1,2 and Y[1, 1] is out
# of range so an error is raised
raises(IndexError, lambda: X[1, 1].subs(X, Y))
# here, [0, 1] is in range so the subs succeeds
assert X[0, 1].subs(X, Y) == Y[0, 1]
# and here the size of n will accept any index
# in the first position
assert W[2, 1].subs(W, Z) == Z[2, 1]
# but not in the second position
raises(IndexError, lambda: W[2, 2].subs(W, Z))
# any matrix should raise if invalid
raises(IndexError, lambda: W[2, 2].subs(W, zeros(2)))
A = SparseMatrix([[1, 2], [3, 4]])
B = Matrix([[1, 2], [3, 4]])
C, D = MatrixSymbol('C', 2, 2), MatrixSymbol('D', 2, 2)
assert (C * D).subs({C: A, D: B}) == MatMul(A, B)
def test_matmul_simplify():
A = MatrixSymbol('A', 1, 1)
assert simplify(MatMul(A, ImmutableMatrix([[sin(x)**2 + cos(x)**2]]))) == \
MatMul(A, ImmutableMatrix([[1]]))
def test_arrayexpr_convert_array_to_diagonalized_vector():
# Check matrix recognition over trivial dimensions:
cg = ArrayTensorProduct(a, b)
assert convert_array_to_matrix(cg) == a * b.T
cg = ArrayTensorProduct(I1, a, b)
assert convert_array_to_matrix(cg) == a * b.T
# Recognize trace inside a tensor product:
cg = ArrayContraction(ArrayTensorProduct(A, B, C), (0, 3), (1, 2))
assert convert_array_to_matrix(cg) == Trace(A * B) * C
# Transform diagonal operator to contraction:
cg = ArrayDiagonal(ArrayTensorProduct(A, a), (1, 2))
assert _array_diag2contr_diagmatrix(cg) == ArrayContraction(ArrayTensorProduct(A, OneArray(1), DiagMatrix(a)), (1, 3))
assert convert_array_to_matrix(cg) == A * DiagMatrix(a)
cg = ArrayDiagonal(ArrayTensorProduct(a, b), (0, 2))
assert _array_diag2contr_diagmatrix(cg) == PermuteDims(
ArrayContraction(ArrayTensorProduct(DiagMatrix(a), OneArray(1), b), (0, 3)), [1, 2, 0]
)
assert convert_array_to_matrix(cg) == b.T * DiagMatrix(a)
cg = ArrayDiagonal(ArrayTensorProduct(A, a), (0, 2))
assert _array_diag2contr_diagmatrix(cg) == ArrayContraction(ArrayTensorProduct(A, OneArray(1), DiagMatrix(a)), (0, 3))
assert convert_array_to_matrix(cg) == A.T * DiagMatrix(a)
cg = ArrayDiagonal(ArrayTensorProduct(I, x, I1), (0, 2), (3, 5))
assert _array_diag2contr_diagmatrix(cg) == ArrayContraction(ArrayTensorProduct(I, OneArray(1), I1, DiagMatrix(x)), (0, 5))
assert convert_array_to_matrix(cg) == DiagMatrix(x)
cg = ArrayDiagonal(ArrayTensorProduct(I, x, A, B), (1, 2), (5, 6))
assert _array_diag2contr_diagmatrix(cg) == ArrayDiagonal(ArrayContraction(ArrayTensorProduct(I, OneArray(1), A, B, DiagMatrix(x)), (1, 7)), (5, 6))
# TODO: this is returning a wrong result:
# convert_array_to_matrix(cg)
cg = ArrayDiagonal(ArrayTensorProduct(I1, a, b), (1, 3, 5))
assert convert_array_to_matrix(cg) == a*b.T
cg = ArrayDiagonal(ArrayTensorProduct(I1, a, b), (1, 3))
assert _array_diag2contr_diagmatrix(cg) == ArrayContraction(ArrayTensorProduct(OneArray(1), a, b, I1), (2, 6))
assert convert_array_to_matrix(cg) == a*b.T
cg = ArrayDiagonal(ArrayTensorProduct(x, I1), (1, 2))
assert isinstance(cg, ArrayDiagonal)
assert cg.diagonal_indices == ((1, 2),)
assert convert_array_to_matrix(cg) == x
cg = ArrayDiagonal(ArrayTensorProduct(x, I), (0, 2))
assert _array_diag2contr_diagmatrix(cg) == ArrayContraction(ArrayTensorProduct(OneArray(1), I, DiagMatrix(x)), (1, 3))
assert convert_array_to_matrix(cg).doit() == DiagMatrix(x)
raises(ValueError, lambda: ArrayDiagonal(x, (1,)))
# Ignore identity matrices with contractions:
cg = ArrayContraction(ArrayTensorProduct(I, A, I, I), (0, 2), (1, 3), (5, 7))
assert cg.split_multiple_contractions() == cg
assert convert_array_to_matrix(cg) == Trace(A) * I
cg = ArrayContraction(ArrayTensorProduct(Trace(A) * I, I, I), (1, 5), (3, 4))
assert cg.split_multiple_contractions() == cg
assert convert_array_to_matrix(cg).doit() == Trace(A) * I
# Add DiagMatrix when required:
cg = ArrayContraction(ArrayTensorProduct(A, a), (1, 2))
assert cg.split_multiple_contractions() == cg
assert convert_array_to_matrix(cg) == A * a
cg = ArrayContraction(ArrayTensorProduct(A, a, B), (1, 2, 4))
assert cg.split_multiple_contractions() == ArrayContraction(ArrayTensorProduct(A, DiagMatrix(a), OneArray(1), B), (1, 2), (3, 5))
assert convert_array_to_matrix(cg) == A * DiagMatrix(a) * B
cg = ArrayContraction(ArrayTensorProduct(A, a, B), (0, 2, 4))
assert cg.split_multiple_contractions() == ArrayContraction(ArrayTensorProduct(A, DiagMatrix(a), OneArray(1), B), (0, 2), (3, 5))
assert convert_array_to_matrix(cg) == A.T * DiagMatrix(a) * B
cg = ArrayContraction(ArrayTensorProduct(A, a, b, a.T, B), (0, 2, 4, 7, 9))
assert cg.split_multiple_contractions() == ArrayContraction(ArrayTensorProduct(A, DiagMatrix(a), OneArray(1),
DiagMatrix(b), OneArray(1), DiagMatrix(a), OneArray(1), B),
(0, 2), (3, 5), (6, 9), (8, 12))
assert convert_array_to_matrix(cg) == A.T * DiagMatrix(a) * DiagMatrix(b) * DiagMatrix(a) * B.T
cg = ArrayContraction(ArrayTensorProduct(I1, I1, I1), (1, 2, 4))
assert cg.split_multiple_contractions() == ArrayContraction(ArrayTensorProduct(I1, I1, OneArray(1), I1), (1, 2), (3, 5))
assert convert_array_to_matrix(cg) == 1
cg = ArrayContraction(ArrayTensorProduct(I, I, I, I, A), (1, 2, 8), (5, 6, 9))
assert convert_array_to_matrix(cg.split_multiple_contractions()).doit() == A
cg = ArrayContraction(ArrayTensorProduct(A, a, C, a, B), (1, 2, 4), (5, 6, 8))
expected = ArrayContraction(ArrayTensorProduct(A, DiagMatrix(a), OneArray(1), C, DiagMatrix(a), OneArray(1), B), (1, 3), (2, 5), (6, 7), (8, 10))
assert cg.split_multiple_contractions() == expected
assert convert_array_to_matrix(cg) == A * DiagMatrix(a) * C * DiagMatrix(a) * B
cg = ArrayContraction(ArrayTensorProduct(a, I1, b, I1, (a.T*b).applyfunc(cos)), (1, 2, 8), (5, 6, 9))
expected = ArrayContraction(ArrayTensorProduct(a, I1, OneArray(1), b, I1, OneArray(1), (a.T*b).applyfunc(cos)),
(1, 3), (2, 10), (6, 8), (7, 11))
assert cg.split_multiple_contractions().dummy_eq(expected)
assert convert_array_to_matrix(cg).doit().dummy_eq(MatMul(a, (a.T * b).applyfunc(cos), b.T))
def test_recognize_diagonalized_vectors():
a = MatrixSymbol("a", k, 1)
b = MatrixSymbol("b", k, 1)
A = MatrixSymbol("A", k, k)
B = MatrixSymbol("B", k, k)
C = MatrixSymbol("C", k, k)
X = MatrixSymbol("X", k, k)
x = MatrixSymbol("x", k, 1)
I1 = Identity(1)
I = Identity(k)
# Check matrix recognition over trivial dimensions:
cg = CodegenArrayTensorProduct(a, b)
assert recognize_matrix_expression(cg) == a * b.T
cg = CodegenArrayTensorProduct(I1, a, b)
assert recognize_matrix_expression(cg) == a * I1 * b.T
# Recognize trace inside a tensor product:
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, B, C), (0, 3),
(1, 2))
assert recognize_matrix_expression(cg) == Trace(A * B) * C
# Transform diagonal operator to contraction:
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(A, a), (1, 2))
assert cg.transform_to_product() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a)), (1, 2))
assert recognize_matrix_expression(cg) == A * DiagMatrix(a)
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(a, b), (0, 2))
assert cg.transform_to_product() == CodegenArrayContraction(
CodegenArrayTensorProduct(DiagMatrix(a), b), (0, 2))
assert recognize_matrix_expression(cg).doit() == DiagMatrix(a) * b
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(A, a), (0, 2))
assert cg.transform_to_product() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a)), (0, 2))
assert recognize_matrix_expression(cg) == A.T * DiagMatrix(a)
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(I, x, I1), (0, 2),
(3, 5))
assert cg.transform_to_product() == CodegenArrayContraction(
CodegenArrayTensorProduct(I, DiagMatrix(x), I1), (0, 2))
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(I, x, A, B), (1, 2),
(5, 6))
assert cg.transform_to_product() == CodegenArrayDiagonal(
CodegenArrayContraction(
CodegenArrayTensorProduct(I, DiagMatrix(x), A, B), (1, 2)), (3, 4))
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(x, I1), (1, 2))
assert isinstance(cg, CodegenArrayDiagonal)
assert cg.diagonal_indices == ((1, 2), )
assert recognize_matrix_expression(cg) == x
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(x, I), (0, 2))
assert cg.transform_to_product() == CodegenArrayContraction(
CodegenArrayTensorProduct(DiagMatrix(x), I), (0, 2))
assert recognize_matrix_expression(cg).doit() == DiagMatrix(x)
cg = CodegenArrayDiagonal(x, (1, ))
assert cg == x
# Ignore identity matrices with contractions:
cg = CodegenArrayContraction(CodegenArrayTensorProduct(I, A, I, I), (0, 2),
(1, 3), (5, 7))
assert cg.split_multiple_contractions() == cg
assert recognize_matrix_expression(cg) == Trace(A) * I
cg = CodegenArrayContraction(CodegenArrayTensorProduct(Trace(A) * I, I, I),
(1, 5), (3, 4))
assert cg.split_multiple_contractions() == cg
assert recognize_matrix_expression(cg).doit() == Trace(A) * I
# Add DiagMatrix when required:
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a), (1, 2))
assert cg.split_multiple_contractions() == cg
assert recognize_matrix_expression(cg) == A * a
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, B), (1, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a), B), (1, 2), (3, 4))
assert recognize_matrix_expression(cg) == A * DiagMatrix(a) * B
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, B), (0, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a), B), (0, 2), (3, 4))
assert recognize_matrix_expression(cg) == A.T * DiagMatrix(a) * B
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, b, a.T, B),
(0, 2, 4, 7, 9))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a), DiagMatrix(b),
DiagMatrix(a), B), (0, 2), (3, 4), (5, 7),
(6, 9))
assert recognize_matrix_expression(
cg).doit() == A.T * DiagMatrix(a) * DiagMatrix(b) * DiagMatrix(a) * B.T
cg = CodegenArrayContraction(CodegenArrayTensorProduct(I1, I1, I1),
(1, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(I1, I1, I1), (1, 2), (3, 4))
assert recognize_matrix_expression(cg).doit() == Identity(1)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(I, I, I, I, A),
(1, 2, 8), (5, 6, 9))
assert recognize_matrix_expression(
cg.split_multiple_contractions()).doit() == A
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, C, a, B),
(1, 2, 4), (5, 6, 8))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagMatrix(a), C, DiagMatrix(a), B),
(1, 2), (3, 4), (5, 6), (7, 8))
assert recognize_matrix_expression(
cg) == A * DiagMatrix(a) * C * DiagMatrix(a) * B
cg = CodegenArrayContraction(
CodegenArrayTensorProduct(a, I1, b, I1, (a.T * b).applyfunc(cos)),
(1, 2, 8), (5, 6, 9))
assert cg.split_multiple_contractions().dummy_eq(
CodegenArrayContraction(
CodegenArrayTensorProduct(a, I1, b, I1, (a.T * b).applyfunc(cos)),
(1, 2), (3, 8), (5, 6), (7, 9)))
assert recognize_matrix_expression(cg).dummy_eq(
MatMul(a, I1, (a.T * b).applyfunc(cos), Transpose(I1), b.T))
cg = CodegenArrayContraction(
CodegenArrayTensorProduct(A.T, a, b, b.T, (A * X * b).applyfunc(cos)),
(1, 2, 8), (5, 6, 9))
assert cg.split_multiple_contractions().dummy_eq(
CodegenArrayContraction(
CodegenArrayTensorProduct(A.T, DiagMatrix(a), b, b.T,
(A * X * b).applyfunc(cos)), (1, 2),
(3, 8), (5, 6, 9)))
# assert recognize_matrix_expression(cg)
# Check no overlap of lines:
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, C, a, B),
(1, 2, 4), (5, 6, 8), (3, 7))
assert cg.split_multiple_contractions() == cg
cg = CodegenArrayContraction(CodegenArrayTensorProduct(a, b, A), (0, 2, 4),
(1, 3))
assert cg.split_multiple_contractions() == cg
def test_MatMul_kind():
M = Matrix([[1, 2], [3, 4]])
assert MatMul(2, M).kind is MatrixKind(NumberKind)
assert MatMul(comm_x, M).kind is MatrixKind(NumberKind)
def test_matrixify():
n, m, l = symbols('n m l')
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
assert matrixify(n + m) == n + m
assert matrixify(Mul(A, B)) == MatMul(A, B)
def test_recognize_diagonalized_vectors():
a = MatrixSymbol("a", k, 1)
b = MatrixSymbol("b", k, 1)
A = MatrixSymbol("A", k, k)
B = MatrixSymbol("B", k, k)
C = MatrixSymbol("C", k, k)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a), (1, 2))
assert cg.split_multiple_contractions() == cg
assert recognize_matrix_expression(cg) == A * a
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, B), (1, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagonalizeVector(a), B), (1, 2), (3, 4))
assert recognize_matrix_expression(cg) == A * DiagonalizeVector(a) * B
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, B), (0, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagonalizeVector(a), B), (0, 2), (3, 4))
assert recognize_matrix_expression(cg) == A.T * DiagonalizeVector(a) * B
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, b, a.T, B),
(0, 2, 4, 7, 9))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A,
DiagonalizeVector(a), DiagonalizeVector(b),
DiagonalizeVector(a), B), (0, 2), (3, 4),
(5, 7), (6, 9))
assert recognize_matrix_expression(cg).doit() == A.T * DiagonalizeVector(
a) * DiagonalizeVector(b) * DiagonalizeVector(a) * B.T
I1 = Identity(1)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(I1, I1, I1),
(1, 2, 4))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(I1, I1, I1), (1, 2), (3, 4))
assert recognize_matrix_expression(cg).doit() == Identity(1)
I = Identity(k)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(I, I, I, I, A),
(1, 2, 8), (5, 6, 9))
assert recognize_matrix_expression(
cg.split_multiple_contractions()).doit() == A
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, C, a, B),
(1, 2, 4), (5, 6, 8))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(A, DiagonalizeVector(a), C,
DiagonalizeVector(a), B), (1, 2), (3, 4),
(5, 6), (7, 8))
assert recognize_matrix_expression(
cg) == A * DiagonalizeVector(a) * C * DiagonalizeVector(a) * B
cg = CodegenArrayContraction(
CodegenArrayTensorProduct(a, I1, b, I1, (a.T * b).applyfunc(cos)),
(1, 2, 8), (5, 6, 9))
assert cg.split_multiple_contractions() == CodegenArrayContraction(
CodegenArrayTensorProduct(a, I1, b, I1, (a.T * b).applyfunc(cos)),
(1, 2), (3, 8), (5, 6), (7, 9))
assert recognize_matrix_expression(cg) == MatMul(a, I1,
(a.T * b).applyfunc(cos),
Transpose(I1), b.T)
# Check no overlap of lines:
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, a, C, a, B),
(1, 2, 4), (5, 6, 8), (3, 7))
raises(ValueError, lambda: cg.split_multiple_contractions())
cg = CodegenArrayContraction(CodegenArrayTensorProduct(a, b, A), (0, 2, 4),
(1, 3))
raises(ValueError, lambda: cg.split_multiple_contractions())
