function deltG=func_deltG(Busnum,PVi,GB,Volt,UAngel,indexi,indexj,PGi)
dg1_dPg=eye(size(PGi,1));
dg2_dPg=zeros(size(PGi,1));
dg3_dPg=zeros(size(PGi,1),Busnum);
dg4_dPg=zeros(size(PGi,1),Busnum);

%% 
dg1_dQr=zeros(size(PVi,1));
dg2_dQr=eye(size(PVi,1));
dg3_dQr=zeros(size(PVi,1),Busnum);
dg4_dQr=zeros(size(PVi,1),Busnum);
%% 
dg1_dx=zeros(2*Busnum,2);
dg2_dx=zeros(2*Busnum,2);
dg3_dx=zeros(2*Busnum,Busnum);
for I=1:Busnum
    dg3_dx(2*I,I)=1;
end

dg4_dx=zeros(2*Busnum,Busnum);
indexi=indexi';
indexj=indexj';

%% 线路
t1=Volt(indexi).*Volt(indexj);
t2=real(...
        GB( ...
                 sub2ind(size(GB),indexi,indexj) ...
            ...
         )...
       ).*...
    sin(...
        UAngel(indexi)'-UAngel(indexj)'... 
        );
     
 t3=imag(... 
            GB( sub2ind(size(GB),indexi,indexj)  )...
        ).*... 
    cos(...
        UAngel(indexi)'-UAngel(indexj)'...
        );
dPij_dThytai=t1.*(t2-t3)';
%%
t1=-Volt(indexj);
t2=real(...
        GB( ...
                 sub2ind(size(GB),indexi,indexj) ...
            ...
         )...
       ).*...
    cos(...
        UAngel(indexi)'-UAngel(indexj)' ...
        );
    
 t3=imag(... 
            GB( sub2ind(size(GB),indexi,indexj)  )...
        ).*... 
    sin(...
        UAngel(indexi)'-UAngel(indexj)'...
        );
     
 t4=2*Volt(indexi).*real(... 
            GB( sub2ind(size(GB),indexi,indexj)  )...
        )';
dPij_dVi=t4+t1.*(t2+t3)';
dPij_dVj=-Volt(indexi).*(t2+t3)';
%% 开始形成dg4_dx
for I=1:size(indexi,1)
    dg4_dx(2*indexi(I)-1,I)=dPij_dThytai(I);
    dg4_dx(2*indexj(I)-1,I)=-dPij_dThytai(I);
    dg4_dx(2*indexi(I),I)=dPij_dVi(I);
    dg4_dx(2*indexj(I),I)=dPij_dVj(I);
end
%% 
deltG=[dg1_dPg,dg2_dPg,dg3_dPg,dg4_dPg;
       dg1_dQr,dg2_dQr,dg3_dQr,dg4_dQr;
       dg1_dx,dg2_dx,dg3_dx,dg4_dx;
];