def test_tensorsymmetry():
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
sym = tensorsymmetry([1] * 2)
sym1 = TensorSymmetry(get_symmetric_group_sgs(2))
assert sym == sym1
sym = tensorsymmetry([2])
sym1 = TensorSymmetry(get_symmetric_group_sgs(2, 1))
assert sym == sym1
sym2 = tensorsymmetry()
assert sym2.base == Tuple() and sym2.generators == Tuple(Permutation(1))
raises(NotImplementedError, lambda: tensorsymmetry([2, 1]))
def test_tensor_element():
L = TensorIndexType("L")
i, j, k, l, m, n = tensor_indices("i j k l m n", L)
A = TensorHead("A", [L, L], TensorSymmetry.no_symmetry(2))
a = A(i, j)
assert isinstance(TensorElement(a, {}), Tensor)
assert isinstance(TensorElement(a, {k: 1}), Tensor)
te1 = TensorElement(a, {Symbol("i"): 1})
assert te1.free == [(j, 0)]
assert te1.get_free_indices() == [j]
assert te1.dum == []
te2 = TensorElement(a, {i: 1})
assert te2.free == [(j, 0)]
assert te2.get_free_indices() == [j]
assert te2.dum == []
assert te1 == te2
array = Array([[1, 2], [3, 4]])
assert te1.replace_with_arrays({A(i, j): array}, [j]) == array[1, :]
metric(LorentzIndex,LorentzIndex)
"""
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.matrices.dense import eye
from sympy.matrices.expressions.trace import trace
from sympy.tensor.tensor import TensorIndexType, TensorIndex,\
TensMul, TensAdd, tensor_mul, Tensor, TensorHead, TensorSymmetry
# DiracSpinorIndex = TensorIndexType('DiracSpinorIndex', dim=4, dummy_name="S")
LorentzIndex = TensorIndexType('LorentzIndex', dim=4, dummy_name="L")
GammaMatrix = TensorHead("GammaMatrix", [LorentzIndex],
TensorSymmetry.no_symmetry(1),
comm=None)
def extract_type_tens(expression, component):
"""
Extract from a ``TensExpr`` all tensors with `component`.
Returns two tensor expressions:
* the first contains all ``Tensor`` of having `component`.
* the second contains all remaining.
"""
if isinstance(expression, Tensor):
"""
from sympy import S, Mul, eye, trace
from sympy.tensor.tensor import TensorIndexType, TensorIndex,\
TensMul, TensAdd, tensor_mul, Tensor, TensorHead, TensorSymmetry
from sympy.core.compatibility import range
# DiracSpinorIndex = TensorIndexType('DiracSpinorIndex', dim=4, dummy_fmt="S")
LorentzIndex = TensorIndexType('LorentzIndex', dim=4, dummy_fmt="L")
GammaMatrix = TensorHead("GammaMatrix", [LorentzIndex],
TensorSymmetry.no_symmetry(1), comm=None)
def extract_type_tens(expression, component):
"""
Extract from a ``TensExpr`` all tensors with `component`.
Returns two tensor expressions:
* the first contains all ``Tensor`` of having `component`.
* the second contains all remaining.
"""
if isinstance(expression, Tensor):
sp = [expression]