def _check_symbolic_index(self, index):
# Check if any index is symbolic:
tuple_index = (index if isinstance(index, tuple) else (index,))
if any([(isinstance(i, Expr) and (not i.is_number)) for i in tuple_index]):
for i, nth_dim in zip(tuple_index, self.shape):
if ((i < 0) == True) or ((i >= nth_dim) == True):
raise ValueError("index out of range")
from sympy.tensor import Indexed
return Indexed(self, *tuple_index)
return None
def test_Indexed_subs():
i, j, k = symbols('i j k', integer=True)
a, b = symbols('a b')
A = Indexed(a)
B = Indexed(b)
assert A == B.subs(b, a)
def __getitem__(self, indices, **kw_args):
if is_sequence(indices):
# Special case needed because M[*my_tuple] is a syntax error.
return Indexed(self, *indices, **kw_args)
else:
return Indexed(self, indices, **kw_args)