Internal function for parameter initialization
        Return a vector of random scales

def _getScalesRand(self):
        """
        Internal function for parameter initialization
        Return a vector of random scales
        """
        if self.P>1:
            scales = []
            for term_i in range(self.n_randEffs):
                _scales = sp.randn(self.diag[term_i].shape[0])
                if self.jitter[term_i]>0:
                    _scales = sp.concatenate((_scales,sp.array([sp.sqrt(self.jitter[term_i])])))
                scales.append(_scales)
            scales = sp.concatenate(scales)
        else:
            scales=sp.randn(self.vd.getNumberScales())
        return scales