probdist.c

   1 #include <assert.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 #include "move.h"
   7 #include "probdist.h"
   8 #include "random.h"
   9 #include "board.h"
  10
  11 int
  12 probdist_pick(struct probdist *pd, int *ignore)
  13 {
  14         double total = probdist_total(pd) - PROBDIST_EPSILON;
  15         assert(total >= 0);
  16         double stab = fast_frandom() * total;
  17         //fprintf(stderr, "stab %f / %f\n", stab, total);
  18         for (int i = 0; i < pd->n; i++) {
  19                 //struct board b = { .size = 11 };
  20                 //fprintf(stderr, "[%s] %f (%f)\n", coord2sstr(i, &b), pd->items[i], stab);
  21                 if (*ignore && i == *ignore) {
  22                         ignore++;
  23                         continue;
  24                 }
  25                 if (stab <= pd->items[i])
  26                         return i;
  27                 stab -= pd->items[i];
  28         }
  29         fprintf(stderr, "overstab %f (total %f)\n", stab, total);
  30         assert(0);
  31         return -1;
  32 }