True for a (2, 2, 2, 2) tensor whose 4x4 reshape is unitary.
The (2, 2, 2, 2) layout is the canonical storage of a 2-qubit gate
(axes: out_ctrl, out_tgt, in_ctrl, in_tgt). We reshape to 4x4 and apply
the standard unitarity check.
- Parameters:
-
- Return type:
bool
