[petsc-users] transfer vector data diagonally on DA

Hi,  I want to transfer vector data diagonally in the DA grid like   for (k=zs; k<zs+zm; k++) {   for (j=ys; j<ys+ym; j++) {   for (i=xs; i<xs+xm; i++) { if(i!=mx-1 || j!=my-1 || k!=mz-1){ u_new[k+1][j+1][i+1]=u[k][j][i];} }}} Could you please suggest the best way to do it minimizing interprocessor assignments. Thanks in advance.