time_tools.py 文件源码

def make_residual_func(samples, indices, **params):
    'closure for residual func'
    fft_size = 2
    while fft_size < indices[-1]:
        fft_size *= 2
    freqs = rfftfreq(fft_size, 5)
    ind_from = int(round(1/(params['t_max']*freqs[1])))
    ind_to = ind_from+params['n_harm']
    def make_series(x):
        'Calculates time series from parameterized spectrum'
        nonlocal freqs, ind_from, ind_to, params
        spectrum = zeros_like(freqs, 'complex')
        sign_x0 = 0 if x[0] == 0.5 else abs(x[0]-0.5)/(x[0]-0.5)
        spectrum[0] = rect(sign_x0*exp(params['scale'][0]*abs(x[0]-0.5)), 0)
        for i in range(ind_from, ind_to):
            spectrum[i] = rect(
                exp(params['scale'][1]*x[1]+params['slope']*log(freqs[i])),
                params['scale'][2]*x[2+i-ind_from]
            )
        return irfft(spectrum)
    def residual_func(x):
        'calculates sum of squared residuals'
        nonlocal samples, indices
        series = make_series(x)
        sum_err = 0
        for position, ind in enumerate(indices):
            sum_err += (series[ind]-samples[position])**2
        return sum_err
    return make_series, residual_func