spyrit.misc.walsh_hadamard.iwalsh_S

spyrit.misc.walsh_hadamard.iwalsh_S(s, T=None)

Return the inverse Walsh S-transform of s

Args:

x (np.ndarray): n-by-1 signal. n+1 should be a power of two.

Returns:

np.ndarray: n-by-1 inverse transformed signal

Examples:

Inverse S-transform of a 4095-by-1 signal

>>> import spyrit.misc.walsh_hadamard as wh
>>> import numpy as np
>>> x = np.random.rand(4095,1)
>>> s = wh.walsh_S(x)
>>> y = wh.iwalsh_S(s)
>>> err = np.linalg.norm(1-y/x)
>>> print(f'Error: {err}')