fits.py 文件源码

def fit_rabi(xdata, ydata):
    """Analyze Rabi amplitude data to find pi-pulse amplitude and phase offset.
        Arguments:
            xdata: ndarray of calibration amplitudes. length should be even.
            ydata: measurement amplitudes
        Returns:
            pi_amp: Fitted amplitude of pi pulsed
            offset: Fitted mixer offset
            fit_pts: Fitted points."""

    #seed Rabi frequency from largest FFT component
    N = len(ydata)
    yfft = fft(ydata)
    f_max_ind = np.argmax(np.abs(yfft[1:N//2]))
    f_0 = 0.5 * max([1, f_max_ind]) / xdata[-1]
    amp_0 = 0.5*(ydata.max() - ydata.min())
    offset_0 = np.mean(ydata)
    phase_0 = 0
    if ydata[N//2 - 1] > offset_0:
        amp_0 = -amp_0
    popt, _ = curve_fit(rabi_model, xdata, ydata, [offset_0, amp_0, f_0, phase_0])
    f_rabi = np.abs(popt[2])
    pi_amp = 0.5/f_rabi
    offset = popt[3]
    return pi_amp, offset, popt