Code for periodizing a signal in Fourier (corresponds to subsampling in signal space)

periodize.py

# Code for periodizing a signal in Fourier (corresponds to subsampling in signal space)

def periodize_1d(array, axis, downsampling):
    axis_shape = array.shape[axis]
    before_shape = array.shape[:axis]
    after_shape = array.shape[axis + 1:]
    new_shape = before_shape + (downsampling, -1) + after_shape
    return array.reshape(new_shape).mean(axis)


def periodize(array, axes, stride):
    axes = tuple(np.atleast_1d(axes))
    downsampling = tuple(np.atleast_1d(stride))
    if len(downsampling) == 1:
        downsampling = downsampling * len(axes)
    for axis, ds in zip(axes, downsampling):
        array = periodize_1d(array, axis, ds)
    return array