Re: Random numbers generation

[Christian Holm Christensen <cholm@nbi.dk>]

Hi there,

On Wed, 2005-12-07 at 13:51 -0300, Lisandro Damian Nicanor Perez Meyer
wrote:
> ¿Is there any way of making differents results without having to change the 
> seed from "the outside"?

If you want a `random' seed for the `random number generator' you can
use the current time, as turned by `time'.  Used with a command line
option, is even better. 

  int main(int argc, char** argv) 
  {
     int seed = 0, default_seed = 0;
     for (int i = 1; i < argc; i++) {
         if (argv[i][0] == '-') {
            switch (argv[i][1]) {
            case 's':   seed = strtol(argv[i+1], NULL, 0); i++; break;
            case 'd':   default_seed = 1;  break;
	    ... 
     }
     gsl_rng_env_setup();
     if (!getenv("GSL_RNG_SEED")) { 
       if (seed == 0) seed = time();
       if (default_seed) seed = 0;
       gsl_rng_set(r, seed);
     }
     else {
       ...
     }
     ...
  }

Yours,

-- 
 ___  |  Christian Holm Christensen 
  |_| |  -------------------------------------------------------------
    | |  Address: Sankt Hansgade 23, 1. th.  Phone:  (+45) 35 35 96 91
     _|           DK-2200 Copenhagen N       Cell:   (+45) 24 61 85 91
    _|            Denmark                    Office: (+45) 353  25 404
 ____|   Email:   cholm@nbi.dk               Web:    www.nbi.dk/~cholm
 | |