m=4;n=3;a=1:m*n;
A=reshape(a,m,n)
I=[1,2,4];J=[2,3];
M=A(I,J)
A(I,J)=0
A(I,J)=A(I,J)-M
A(I,J)=A(I,J)+1
A(I,J)=A(I,J)+[1,2]
A(I,J)=A(I,J)+[1;2;3]
