numpy einsum and reshape can't have order=None

[yslan]

Not sure whether this related to the numpy version (mine is 1.24).
However, order = None fails since inside numpy it will try to do upper().

I suggest to set default order to 'C' unless we have decided to change everything into 'F'ortran ordering

SemPy/sempy/kron.py

Line 4 in 202123f

def kron_2d(Sy, Sx, U, order=None):

SemPy/sempy/kron.py

Line 17 in 202123f

def kron(Sz, Sy, Sx, U, order=None):

[thilinarmtb]

Sounds good !