On Thu, Mar 4, 2010 at 8:54 AM, Ted Dunning <ted.dunn...@gmail.com> wrote:
> I haven't examined the out-of-core scenarios at all, but in-memory, it is > possible to have labels with no performance cost if you assume add the > constraint that labeled matrices are only conformable if they share the > identical label dictionary. That implies that you can use the internal row > and column indexes for all internal operations. Care to elaborate? If you're multiplying two a matrix by a vector, both labeled by Map<Integer,String> and reverse Map<String,Integer> for both the rows and columns (and they match in the right way), what is the fast way to do the individual dot products, which performs comparably to walking the sparse int[] / double[] parallel arrays? -jake
