Flags solutions with amplitude more than threshold larger than median.

def flagants(self, threshold=50):
        """ Flags solutions with amplitude more than threshold larger than median.
        """

        # identify very low gain amps not already flagged
        badsols = n.where( (n.median(self.amp)/self.amp > threshold) & (self.flagged == False))[0]
        if len(badsols):
            self.logger.info('Solutions %s flagged (times %s, ants %s, freqs %s) for low gain amplitude.' % (str(badsols), self.mjd[badsols], self.antname[badsols], self.ifid[badsols]))
            for sol in badsols:
                self.flagged[sol] = True