On Thu, Feb 12, 2009 at 10:58, Michael S. Gilbert <michael.s.gilb...@gmail.com> wrote: > On Fri, 6 Feb 2009 18:18:44 -0500 "Michael S. Gilbert" wrote: >> BTW, there is a 64-bit version of the reference mersenne twister >> implementation available [1]. > > I did some testing with this 64-bit implementation (mt19937-64). I've > found that it is actually slower than the 32-bit reference (mt19937ar) > on 64-bit systems (2.15s vs 2.25s to generate 100000000 ints). This is > likely because it generates 64-bit long long ints instead of 32-bit > long ints. However, it should be possible to break up each 64-bit int > into two 32-bit ints, then the runtime would appear to be almost twice > as fast.
Why do you think that? > One other consideration to keep in mind is that the 64-bit > version is not stream-compatible with the 32-bit implementation (you > will get different sequences for the same input seed). > > Would it be worth it to implement this in numpy in order to get an > almost 2x speedup on 64-bit machines? The incompatibility is a showstopper to replacing the PRNG on any platform. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
