function ddg=func_ddg(PGi,PVi,Busnum,ContrlCount,RestraintCount,Loadi,PD,QD,Init_Z,Init_W)
% ¼ÆËãϵÊý
InitZW=Init_Z+Init_W;
loc=InitZW(length(PGi)+length(PVi)+length(Loadi)*1+Busnum+1:RestraintCount);
PD_=PD(Loadi);
QD_=QD(Loadi);
t1=sparse(length(PGi)+length(PVi),ContrlCount);
t21=sparse(length(PD_),length(PGi)+length(PVi));
t22=diag(sparse(-2./PD_.^2-2*(QD_.^2-PD_.^2)./( PD_.^2+QD_.^2).^2))*diag(loc);%dF/dPdP
t23=diag(sparse(4*PD_.*QD_./(PD_.^2+QD_.^2).^2))*diag(loc); %dF/dPdQ
t24=sparse(length(PD_),2*Busnum);
t31=t21;
t32=t23;
t33=diag(sparse(-2*(PD_.^2-QD_.^2)./(PD_.^2+QD_.^2).^2  ))*diag(loc);
t34=t24;
t4=sparse(Busnum*2,ContrlCount);
ddg=[
    t1;
    t21,t22,t23,t24;
    t31,t32,t33,t34;
    t4;
];
end