function [f]=stream(f)
f(:,:,1)=circshift( squeeze(f(:,:,1)), [+1,+0] );
f(:,:,2)=circshift( squeeze(f(:,:,2)), [+0,+1] );
f(:,:,3)=circshift( squeeze(f(:,:,3)), [-1,+0] );
f(:,:,4)=circshift( squeeze(f(:,:,4)), [+0,-1] );
f(:,:,5)=circshift( squeeze(f(:,:,5)), [+1,+1] );
f(:,:,6)=circshift( squeeze(f(:,:,6)), [-1,+1] );
f(:,:,7)=circshift( squeeze(f(:,:,7)), [-1,-1] );
f(:,:,8)=circshift( squeeze(f(:,:,8)), [+1,-1] );
end