"Nick" wrote in message <firstname.lastname@example.org>... > I would like to do operations on vectors of a matrix efficiently, without memory copying. > For example, say V is KxK, A is Nxp p>k > I want to do X(:,1:K)*V efficiently. As it is currently written, matlab makes a temporary copy of the first K colomns of X and does the multiplication. The primitive BLAS routines can handle this without memory copying: just give it the same pointer to X with different number of columns as input. I would like to realize this speedup without having to go to mex. Is this possible?