TensorProduct bug when the args are a combination of symbols and matrices

[saidctb]

I have this simple example that doesn't work, I'm not so sure if we are allowed to combine such arguments or not, but then why does it work in a certain order and doesn't on the other.

In [37]: from sympy.physics.quantum import TensorProduct

In [38]: from sympy import Symbol, eye

In [39]: a = Symbol('a',commutative=False)

In [40]: TensorProduct(a,eye(1))
Out[40]: axMatrix([[1]])

In [41]: TensorProduct(eye(1),a)

TypeError Traceback (most recent call last)
in ()
----> 1 TensorProduct(eye(1),a)

/usr/local/lib/python3.5/dist-packages/sympy/physics/quantum/tensorproduct.py in new(cls, *args)
120 def new(cls, *args):
121 if isinstance(args[0], (Matrix, numpy_ndarray, scipy_sparse_matrix)):
--> 122 return matrix_tensor_product(*args)
123 c_part, new_args = cls.flatten(sympify(args))
124 c_part = Mul(*c_part)

/usr/local/lib/python3.5/dist-packages/sympy/physics/quantum/matrixutils.py in matrix_tensor_product(*product)
245 """Compute the matrix tensor product of sympy/numpy/scipy.sparse matrices."""
246 if isinstance(product[0], MatrixBase):
--> 247 return _sympy_tensor_product(*product)
248 elif isinstance(product[0], numpy_ndarray):
249 return _numpy_tensor_product(*product)

/usr/local/lib/python3.5/dist-packages/sympy/physics/quantum/matrixutils.py in _sympy_tensor_product(*matrices)
192 if not all(isinstance(m, MatrixBase) for m in matrices):
193 raise TypeError(
--> 194 'Sequence of Matrices expected, got: %s' % repr(matrices)
195 )
196

TypeError: Sequence of Matrices expected, got: (Matrix([[1]]), a)

In [42]:

[ManuelZierl]

it works if u use
from sympy.tensor.functions import TensorProduct

also i'm not sure what you are trying to do but
a = Symbol('a',commutative=False)
is interpreted to the best of my knowledge as a number not a matrix so:

x = Symbol('x',commutative=False)
TensorProduct(x,eye(4))

results in:
⎡x 0 0 0⎤
⎢0 x 0 0⎥
⎢0 0 x 0⎥
⎣0 0 0 x⎦

if you want x to be a Matrix as well (like i would suggest snice you are using the tesorproduct) i would recommend to use MatrixSybols

M = MatrixSymbol('M',2,2)
TensorProduct(eye(2), M)

⎡1 0 0 0⎤
⎢0 1 0 0⎥ ⊗M
⎢0 0 1 0⎥
⎣0 0 0 1⎦

[saidctb]

ah thanks a lot, yes I was trying to use a matrix