Max, That's interesting, where can I read about "giant-stepping the generator"? The wiki article http://en.wikipedia.org/wiki/Linear_congruential_generator doesn't mention distributed processing. Thanks, Peter
On Wed, Aug 21, 2013 at 2:44 PM, Max R. Dechantsreiter < [email protected]> wrote: > Hi Peter, > > > What about the old random number generator: take a 16 bit seed, square it, >> take the middle 16 bits, and repeat. They'd want a large number in order >> (so you can repeat an experiment, or a run of a model, with the same >> "random" numbers), and it's easy to computer sequentially; but if you want >> a million of them it would be nice to distribute the job, but I don't >> think >> you can. But maybe "can't parallelize" isn't the same as "badly >> inefficient >> to parallelize". >> > > Many RNG _can_ be distributed. The enabling characteristic > is the existence of a way to "giant-step" the generator. > This is certainly possible for LCG (LCRNG), such as the one > used throughout NPB I. > > The NPB generator has the form > > x(k+1) = a*x(k) modulo 2**46 (suggested a = 5**13) > > which has period 2**44. > > It could be an interesting excercise: take two generators, > one which can be distributed, one which cannot.... > > Cheers, > > Max >
_______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
