"Bruno Luong" <firstname.lastname@example.org> wrote in message <email@example.com>... > "Matt J" wrote in message <firstname.lastname@example.org>... > > > > > Anyway, my point remains. Sparse matrix multiplication has to perform multiplications with the x(j) somewhere, whereas accumarray, in my tests, does not. So sparse mult. is further handicapped. > > 1) Sparse internally access memory via integer indexing. Your accumarray has to cast doubles (firs input) to integers. ==================
Precasting to uint32 does seem to help!
> 2) Sparse multiplication engine might benefice multi-threading, and other low-level optimization. > > Accumarray is not slow. Just sparse is fast. ================