On Fri, Oct 14, 2011 at 1:08 PM, Ewart Shaw <[email protected]> wrote: > I want to generate pseudorandom sequences that are the same for 32- & 64-bit > J. > I need better statistical properties than the old linear congruential > generator > as in 'roll' & 'deal' at http://www.jsoftware.com/help/release/random.htm .
Have you tried the other random generators the (9!:43) foreign makes available? I'd guess some of them are the same for 32 and 64 bit J. If that fails, > I could implement the 32-bit MT19937 'by hand' in J I'd recommend against that: instead pull in a C library that implements that or some other random generator, such as GSL, with the J foreign interface (15!:). If you have trouble with this, tell me and I'll try to help. You may still have to implement deal if you need it. The case when the right argument isn't too large is implemented in GSL, but the case when the right argument is very large and its left argument is small isn't trivial. If you need this latter case, one implementation can be found in the J source code: this is a very tricky algorithm using a sparse table; a different algorithm is given in Knuth chapter 3.4.2 exercise 15. Ambrus ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
