import numpy as np
%alias_magic t timeit
def pow2_1():
    for step in range(1, 10000):
        if np.abs(np.log2(step) - np.round(np.log2(step))) > 1e-6:
            msg = "Row and column strides must be powers of 2."
            continue
        yield int(np.round(np.log2(step)))

def pow2_2():
    for step in range(1, 10000):
        rlevel = step.bit_length() - 1
        if (step % (1 << rlevel)) != 0:
            msg = "Row and column strides must be powers of 2."
            #raise ValueError(msg)
            continue
        yield rlevel

%%t
levels1 = [rlevel for rlevel in pow2_1()]

%%t
levels2 = [rlevel for rlevel in pow2_2()]

levels1 = [rlevel for rlevel in pow2_1()]
levels2 = [rlevel for rlevel in pow2_2()]
assert len(levels1 == levels2)
assert all(level1 == level2 for level1, level2 in zip(levels1, levels2))