Linalg.py 文件源码

def iter(self):
        '''
        The Lanczos iteration.
        '''
        while len(self.candidates)>0:
            v=self.candidates.pop(0)
            norm=nl.norm(v)
            if norm>self.dtol:
                break
            elif self.niter>=self.nc:
                self.deflations.append(self.niter-self.nc)
        else:
            self.stop=True
        if not self.stop:
            self.vectors[self.niter]=v/norm
            if self.niter-self.nc-1>=0:
                self._T_[self.niter,self.niter-self.nc-1]=norm
            else:
                self.P[self.niter,self.niter-self.nc-1+self.nv0]=norm
            for k,vc in enumerate(self.candidates):
                overlap=np.vdot(self.vectors[self.niter],vc)
                if k+self.niter>=self.nc:
                    self._T_[self.niter,k+self.niter-self.nc]=overlap
                else:
                    self.P[self.niter,self.niter-self.nc+k+self.nv0]=overlap
                vc-=overlap*self.vectors[self.niter]
            v=self.matrix.dot(self.vectors[self.niter])
            for k in xrange(max(self.niter-self.nc-1,0),self.niter):
                self._T_[k,self.niter]=np.conjugate(self._T_[self.niter,k])
                v-=self._T_[k,self.niter]*self.vectors[k]
            for k in it.chain(self.deflations,[self.niter]):
                overlap=np.vdot(self.vectors[k],v)
                if k in set(self.deflations)|{self.niter}:
                    self._T_[k,self.niter]=overlap
                    self._T_[self.niter,k]=np.conjugate(overlap)
                v-=overlap*self.vectors[k]
            self.candidates.append(v)
            if not self.keepstate and self.niter>=self.nc and self.niter-self.nc not in self.deflations: self.vectors[self.niter-self.nc]=None
            self.niter+=1