solvers.py 文件源码

def solution_residual_scalar(gain, x, xwt):
    """Calculate residual across all baselines of gain for point source equivalent visibilities

    :param gain: gain [nant, ...]
    :param x: Point source equivalent visibility [nant, ...]
    :param xwt: Point source equivalent weight [nant, ...]
    :return: residual[...]
    """

    nants, nchan, nrec, _ = gain.shape
    x = x.reshape(nants, nants, nchan, nrec, nrec)

    xwt = xwt.reshape(nants, nants, nchan, nrec, nrec)

    residual = numpy.zeros([nchan, nrec, nrec])
    sumwt = numpy.zeros([nchan, nrec, nrec])

    for ant1 in range(nants):
        for ant2 in range(nants):
            for chan in range(nchan):
                error = x[ant2, ant1, chan, 0, 0] - \
                    gain[ant1, chan, 0, 0] * numpy.conjugate(gain[ant2, chan, 0, 0])
                residual += (error * xwt[ant2, ant1, chan, 0, 0] * numpy.conjugate(error)).real
                sumwt += xwt[ant2, ant1, chan, 0, 0]

    residual[sumwt > 0.0] = numpy.sqrt(residual[sumwt > 0.0] / sumwt[sumwt > 0.0])
    residual[sumwt <= 0.0] = 0.0

    return residual