stats.h

   1 #ifndef ZZGO_STATS_H
   2 #define ZZGO_STATS_H
   3
   4 /* Move statistics; we track how good value each move has. */
   5
   6 struct move_stats {
   7         int playouts; // # of playouts
   8         float value; // BLACK wins/playouts
   9 };
  10
  11 /* Add a result to the stats. */
  12 static void stats_add_result(struct move_stats *s, float result, int playouts);
  13
  14 /* Merge two stats together. */
  15 static void stats_merge(struct move_stats *dest, struct move_stats *src);
  16
  17 /* Reverse stats parity. */
  18 static void stats_reverse_parity(struct move_stats *s);
  19
  20
  21 static inline void
  22 stats_add_result(struct move_stats *s, float result, int playouts)
  23 {
  24         s->playouts += playouts;
  25         s->value += (result - s->value) * playouts / s->playouts;
  26 }
  27
  28 static inline void
  29 stats_merge(struct move_stats *dest, struct move_stats *src)
  30 {
  31         if (src->playouts > 0)
  32                 stats_add_result(dest, src->value, src->playouts);
  33 }
  34
  35 static inline void
  36 stats_reverse_parity(struct move_stats *s)
  37 {
  38         s->value = 1 - s->value;
  39 }
  40
  41 #endif