tebd.py 文件源码

def __newgammaD(self, theta, l):
        """ Apply Eqns. 22-24 in Vidal 2003 to update gamma^D 
            (gamma of the next qbit).
        """
        rhoDK = self.__rhoDK(theta, self.coefs[l-1].lam)    
        #diagonalize
        idx = self.chi * self.hdim
        rhoDKflat = rhoDK.reshape([idx, idx]) 
        evals, evecs = la.eigh(rhoDKflat) #note rho is a density matrix and thus
                                          #hermitian
        evals = evals[:self.chi]
        evecs = evecs[:,:self.chi]
        return evecs