Finds 2x2 special-unitaries A, B where mat = Mag.H @ kron(A, B) @ Mag.

Mag is the magic basis matrix:

1  0  0  i
0  i  1  0
0  i -1  0     (times sqrt(0.5) to normalize)
1  0  0 -i

mat A real 4x4 orthogonal matrix.
rtol Per-matrix-entry relative tolerance on equality.
atol Per-matrix-entry absolute tolerance on equality.
check_preconditions When set, the code verifies that the given matrix is from SO(4). Defaults to set.

A pair (A, B) of matrices in SU(2) such that Mag.H @ kron(A, B) @ Mag is approximately equal to the given matrix.

ValueError Bad matrix.