playout.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5 #include "board.h"
   6 #include "debug.h"
   7 #include "engine.h"
   8 #include "move.h"
   9 #include "playout.h"
  10
  11 int
  12 play_random_game(struct board *b, enum stone starting_color, int gamelen,
  13                  playout_policeman policeman, void *policy)
  14 {
  15         gamelen = gamelen - b->moves;
  16         if (gamelen < 10)
  17                 gamelen = 10;
  18
  19         enum stone color = starting_color;
  20         enum stone policy_color = stone_other(starting_color);
  21         coord_t urgent;
  22
  23         int passes = is_pass(b->last_move.coord);
  24
  25         while (gamelen-- && passes < 2) {
  26                 urgent = policeman(policy, b, policy_color);
  27
  28                 coord_t coord;
  29
  30                 if (!is_pass(urgent)) {
  31                         struct move m;
  32                         m.coord = urgent; m.color = color;
  33                         if (board_play(b, &m) < 0) {
  34                                 if (DEBUGL(8)) {
  35                                         fprintf(stderr, "Urgent move %d,%d is ILLEGAL:\n", coord_x(urgent, b), coord_y(urgent, b));
  36                                         board_print(b, stderr);
  37                                 }
  38                                 goto play_random;
  39                         }
  40                         coord = urgent;
  41                 } else {
  42 play_random:
  43                         board_play_random(b, color, &coord);
  44                 }
  45
  46 #if 0
  47                 /* For UCT, superko test here is downright harmful since
  48                  * in superko-likely situation we throw away literarily
  49                  * 95% of our playouts; UCT will deal with this fine by
  50                  * itself. */
  51                 if (unlikely(b->superko_violation)) {
  52                         /* We ignore superko violations that are suicides. These
  53                          * are common only at the end of the game and are
  54                          * rather harmless. (They will not go through as a root
  55                          * move anyway.) */
  56                         if (group_at(b, coord)) {
  57                                 if (DEBUGL(3)) {
  58                                         fprintf(stderr, "Superko fun at %d,%d in\n", coord_x(coord, b), coord_y(coord, b));
  59                                         if (DEBUGL(4))
  60                                                 board_print(b, stderr);
  61                                 }
  62                                 return -1;
  63                         } else {
  64                                 if (DEBUGL(6)) {
  65                                         fprintf(stderr, "Ignoring superko at %d,%d in\n", coord_x(coord, b), coord_y(coord, b));
  66                                         board_print(b, stderr);
  67                                 }
  68                                 b->superko_violation = false;
  69                         }
  70                 }
  71 #endif
  72
  73                 if (DEBUGL(8)) {
  74                         char *cs = coord2str(coord, b);
  75                         fprintf(stderr, "%s %s\n", stone2str(color), cs);
  76                         free(cs);
  77                 }
  78
  79                 if (unlikely(is_pass(coord))) {
  80                         passes++;
  81                 } else {
  82                         passes = 0;
  83                 }
  84
  85                 color = stone_other(color);
  86         }
  87
  88         float score = board_fast_score(b);
  89         bool result = (starting_color == S_WHITE ? (score > 0) : (score < 0));
  90
  91         if (DEBUGL(6)) {
  92                 fprintf(stderr, "Random playout result: %d (W %f)\n", result, score);
  93                 if (DEBUGL(7))
  94                         board_print(b, stderr);
  95         }
  96
  97         return result;
  98 }