solvers.py 文件源码

def gain_substitution_scalar(gain, x, xwt):
    nants, nchan, nrec, _ = gain.shape
    newgain = numpy.ones_like(gain, dtype='complex')
    gwt = numpy.zeros_like(gain, dtype='float')

    # We are going to work with Jones 2x2 matrix formalism so everything has to be
    # converted to that format
    x = x.reshape(nants, nants, nchan, nrec, nrec)
    xwt = xwt.reshape(nants, nants, nchan, nrec, nrec)

    for ant1 in range(nants):
        for chan in range(nchan):
            # Loop over e.g. 'RR', 'LL, or 'xx', 'YY' ignoring cross terms
            top = numpy.sum(x[:, ant1, chan, 0, 0] *
                            gain[:, chan, 0, 0] * xwt[:, ant1, chan, 0, 0], axis=0)
            bot = numpy.sum((gain[:, chan, 0, 0] * numpy.conjugate(gain[:, chan, 0, 0]) *
                             xwt[:, ant1, chan, 0, 0]).real, axis=0)

            if bot > 0.0:
                newgain[ant1, chan, 0, 0] = top / bot
                gwt[ant1, chan, 0, 0] = bot
            else:
                newgain[ant1, chan, 0, 0] = 0.0
                gwt[ant1, chan, 0, 0] = 0.0
    return newgain, gwt