code/src/Util/rng.h

   1 #ifndef PPAM_RNG_H
   2 #define PPAM_RNG_H
   3
   4 #include <stdint.h>
   5 #include "Util/types.h"
   6
   7 #define INV_RANDMAX 2.3283064370807974E-10 // 1/0xffffffff
   8
   9 // If (flag!=0), then use a random array to initialize mm[]
  10 #define mix(a,b,c,d,e,f,g,h)  \
  11 {                             \
  12     a^=b<<11; d+=a; b+=c;     \
  13     b^=c>>2;  e+=b; c+=d;     \
  14     c^=d<<8;  f+=c; d+=e;     \
  15     d^=e>>16; g+=d; e+=f;     \
  16     e^=f<<10; h+=e; f+=g;     \
  17     f^=g>>4;  a+=f; g+=h;     \
  18     g^=h<<8;  b+=g; h+=a;     \
  19     h^=a>>9;  c+=h; a+=b;     \
  20 }
  21
  22 // initialize the (pseudo-)random generator
  23 // NOTE: flag has only two states, active or not.
  24 //       flag != 0 --> "maximal randomness"
  25 void init_rng(int flag);
  26
  27 // return a (pseudo-)random integer
  28 uint32_t get_rand_int();
  29
  30 // return a (pseudo-)random real number in [0,1]
  31 Real get_rand_real();
  32
  33 #endif