patternprob.h

   1 #ifndef PACHI_PATTERNPROB_H
   2 #define PACHI_PATTERNPROB_H
   3
   4 /* Pattern probability table. */
   5
   6 #include <math.h>
   7
   8 #include "board.h"
   9 #include "move.h"
  10 #include "pattern.h"
  11
  12
  13 /* The pattern probability table considers each pattern as a whole
  14  * (not dividing it to individual features) and stores probability
  15  * of the pattern being played. */
  16
  17 /* The table primary key is the pattern spatial (most distinctive
  18  * feature); within a single primary key chain, the entries are
  19  * unsorted (for now). */
  20
  21 struct pattern_prob {
  22         struct pattern p;
  23         floating_t prob;
  24         struct pattern_prob *next;
  25 };
  26
  27 struct pattern_pdict {
  28         struct pattern_config *pc;
  29
  30         struct pattern_prob **table; /* [pc->spat_dict->nspatials + 1] */
  31 };
  32
  33 /* Initialize the pdict data structure from a given file (pass NULL
  34  * to use default filename). Returns NULL if the file with patterns
  35  * has been found. */
  36 struct pattern_pdict *pattern_pdict_init(char *filename, struct pattern_config *pc);
  37
  38 /* Return probability associated with given pattern. Returns NaN if
  39  * the pattern cannot be found. */
  40 static floating_t pattern_prob(struct pattern_pdict *dict, struct pattern *p);
  41
  42 /* Utility function - extract spatial id from a pattern. If the pattern
  43  * has no spatial feature, it is represented by the highest spatial id
  44  * plus one. */
  45 static uint32_t pattern2spatial(struct pattern_pdict *dict, struct pattern *p);
  46
  47
  48 static inline floating_t
  49 pattern_prob(struct pattern_pdict *dict, struct pattern *p)
  50 {
  51         uint32_t spi = pattern2spatial(dict, p);
  52         for (struct pattern_prob *pb = dict->table[spi]; pb; pb = pb->next)
  53                 if (pattern_eq(p, &pb->p))
  54                         return pb->prob;
  55         return NAN; // XXX: We assume quiet NAN existence
  56 }
  57
  58 static inline uint32_t
  59 pattern2spatial(struct pattern_pdict *dict, struct pattern *p)
  60 {
  61         for (int i = 0; i < p->n; i++)
  62                 if (p->f[i].id == FEAT_SPATIAL)
  63                         return p->f[i].payload;
  64         return dict->pc->spat_dict->nspatials;
  65 }
  66
  67 #endif