- At least 32 bit long int is required, but works with any larger
                 word lengths
            
                    - Reference:
                      This is algorithm "mzran13" from
                      G. Marsaglia and A. Zaman,
                      "Some portable very-long-period random number generators",
                      Computers in Physics, Vol. 8, No. 1, Jan/Feb 1994.
            
                      In the original implementation the algorithm relies on 32-bit
                      arithmetics with implicit modulo 2^32 on overflow. Since the
                      the size of unsigned longs may not always be 32 bit the
                      modulo 2^32 is coded explicitly using masks.
                 The performance loss is not very important.
            
                      The original code reads:
            
                          long s;
                          if (y > x+c) {
                       s = y - (x+c); c = 0;
                          } else {
                       s = y - (x+c) - 18; c = 1;
                          }
                          x = y;
                          y = z;
                          return ((z = s) + (n - 69069 * n + 1013904243));
                                               ^
                                               Here it contains a misprint
                                               Should really be a "=" !