_stockwell.py 文件源码

def _st(x, start_f, windows):
    """Implementation based on Ali Moukadem Matlab code (only used in tests)"""
    n_samp = x.shape[-1]
    ST = np.empty(x.shape[:-1] + (len(windows), n_samp), dtype=np.complex)
    # do the work
    Fx = fftpack.fft(x)
    XF = np.concatenate([Fx, Fx], axis=-1)
    for i_f, window in enumerate(windows):
        f = start_f + i_f
        ST[..., i_f, :] = fftpack.ifft(XF[..., f:f + n_samp] * window)
    return ST