Random Number Generator: Difference between revisions

Implementation according to Wikipedia:

 

#include <stddef.h>

#include <stdint.h>

index++;

return y;

 

Some implementations automatically seed the generator with seed 5489, but this will (obviously) lead to the same outputs at every initialization.

If you are still not satisfied, you may want to build your own PRNG. You can do this in a fairly trial-and-error way by writing something that looks good and subjecting it to automated statistical testing suites such as [http://simul.iro.umontreal.ca/testu01/tu01.html TestU01]'s SmallCrush, Crush and finally BigCrush. These tests are very easy to run and can quickly point out problems, for example:

 

#include <unif01.h>

#include <bbattery.h>

unif01_DeleteExternGenBits(gen);

}

 

SmallCrush will report that this generator failed 12 out of 15 statistical tests. The other tests, which are also much slower, are therefore not necessary.