/********************************************************************

          The McGill Super-Duper Random Number Generator

             G. Marsaglia, K. Ananthanarayana, N. Paul

  

    Incorporating the Ziggurat method of sampling from decreasing

              or symmetric unimodal density functions.

                      G. Marsaglia, W.W. Tsang

  

                 Rewritten into C by E. Schneider

 *********************************************************************/

  

static unsigned long mcgn, srgn;

  

#define MULT 69069L

  

void rstart (long i1, long i2)

{

      mcgn = (unsigned long)((i1 == 0L) ? 0L : i1 | 1L);

      srgn = (unsigned long)((i2 == 0L) ? 0L : (i2 & 0x7FFL) | 1L);

}

  

long uni(void)

{

      unsigned long r0, r1;



      r0 = (srgn >> 15);

      r1 = srgn ^ r0;

      r0 = (r1 << 17);

      srgn = r0 ^ r1;

      mcgn = MULT * mcgn;

      r1 = mcgn ^ srgn;

      return (r1 >> 1);

}

  

long vni(void)

{

      unsigned long r0, r1;



      r0 = (srgn >> 15);

      r1 = srgn ^ r0;

      r0 = (r1 << 17);

      srgn = r0 ^ r1;

      mcgn = MULT * mcgn;

      r1 = mcgn ^ srgn;

      return r1;

}



/* 

"Anyone who consider arithmetic means of producing random number is,

 of course, in a state of sin" - John Von Neumann

*/