DIC_CG.m

function [ E ] = DIC_CG(  Y,E0, B,Z, P,A,mu1 )
% optimize the dictionaries via Conjugate gradient 
 maxIter =30;

 P1=P'*P;
 A1=A*A';
 B1=B*B'+mu1*eye(size(B,1));
 H=P'*Z*A'+mu1*E0+Y*B';
 
 r0=H-E0*B1-P1*E0*A1;
 p0=r0;
 for i=1:maxIter
    pp= (p0*B1+P1*p0*A1);
    pp1=p0(:)'*pp(:);

    a=(r0(:)')*r0(:)/pp1;
         E=E0+a*p0;
         r1=r0-a*pp;
         
         b1=(r1(:)'*r1(:))/(r0(:)'*r0(:));
         p1=r1+b1*p0;
     p0=p1;
     r0=r1;
     E0=E;
 end