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, struct move *m, int gamelen,
  13                  playout_policeman policeman, void *policy)
  14 {
  15         if (b->superko_violation) {
  16                 if (DEBUGL(0)) {
  17                         fprintf(stderr, "\tILLEGAL: superko violation at root!\n");
  18                         board_print(b, stderr);
  19                 }
  20                 return -1;
  21         }
  22
  23         struct board b2;
  24         board_copy(&b2, b);
  25
  26         board_play_random(&b2, m->color, &m->coord);
  27         if (!is_pass(m->coord) && !group_at(&b2, m->coord)) {
  28                 if (DEBUGL(4)) {
  29                         fprintf(stderr, "SUICIDE DETECTED at %d,%d:\n", coord_x(m->coord, b), coord_y(m->coord, b));
  30                         board_print(&b2, stderr);
  31                 }
  32                 board_done_noalloc(&b2);
  33                 return -3;
  34         }
  35
  36         if (DEBUGL(3))
  37                 fprintf(stderr, "[%d,%d] playing random game of color %d\n", coord_x(m->coord, b), coord_y(m->coord, b), m->color);
  38
  39         gamelen = gamelen - b2.moves;
  40         if (gamelen < 10)
  41                 gamelen = 10;
  42
  43         enum stone color = stone_other(m->color);
  44         coord_t urgent;
  45
  46         int passes = is_pass(m->coord);
  47
  48         /* Special check: We probably tenukied the last opponent's move. But
  49          * check if the opponent has lucrative local continuation for her last
  50          * move! */
  51         /* This check is ultra-important BTW. Without it domain checking does
  52          * not bring that much of an advantage. It might even warrant it to by
  53          * default do only this domain check. */
  54         urgent = policeman(policy, b, m->color);
  55         if (!is_pass(urgent))
  56                 goto play_urgent;
  57
  58         while (gamelen-- && passes < 2) {
  59                 urgent = policeman(policy, &b2, m->color);
  60
  61                 coord_t coord;
  62
  63                 if (!is_pass(urgent)) {
  64                         struct move m;
  65 play_urgent:
  66                         m.coord = urgent; m.color = color;
  67                         if (board_play(&b2, &m) < 0) {
  68                                 if (DEBUGL(8)) {
  69                                         fprintf(stderr, "Urgent move %d,%d is ILLEGAL:\n", coord_x(urgent, b), coord_y(urgent, b));
  70                                         board_print(&b2, stderr);
  71                                 }
  72                                 goto play_random;
  73                         }
  74                         coord = urgent;
  75                 } else {
  76 play_random:
  77                         board_play_random(&b2, color, &coord);
  78                 }
  79
  80                 if (unlikely(b2.superko_violation)) {
  81                         /* We ignore superko violations that are suicides. These
  82                          * are common only at the end of the game and are
  83                          * rather harmless. (They will not go through as a root
  84                          * move anyway.) */
  85                         if (group_at(&b2, coord)) {
  86                                 if (DEBUGL(3)) {
  87                                         fprintf(stderr, "Superko fun at %d,%d in\n", coord_x(coord, b), coord_y(coord, b));
  88                                         if (DEBUGL(4))
  89                                                 board_print(&b2, stderr);
  90                                 }
  91                                 board_done_noalloc(&b2);
  92                                 return -2;
  93                         } else {
  94                                 if (DEBUGL(6)) {
  95                                         fprintf(stderr, "Ignoring superko at %d,%d in\n", coord_x(coord, b), coord_y(coord, b));
  96                                         board_print(&b2, stderr);
  97                                 }
  98                                 b2.superko_violation = false;
  99                         }
 100                 }
 101
 102                 if (DEBUGL(8)) {
 103                         char *cs = coord2str(coord, b);
 104                         fprintf(stderr, "%s %s\n", stone2str(color), cs);
 105                         free(cs);
 106                 }
 107
 108                 if (unlikely(is_pass(coord))) {
 109                         passes++;
 110                 } else {
 111                         passes = 0;
 112                 }
 113
 114                 color = stone_other(color);
 115         }
 116
 117         float score = board_fast_score(&b2);
 118         bool result = (m->color == S_WHITE ? (score > 0) : (score < 0));
 119
 120         if (DEBUGL(6)) {
 121                 fprintf(stderr, "Random playout result: %d (W %f)\n", result, score);
 122                 if (DEBUGL(7))
 123                         board_print(&b2, stderr);
 124         }
 125
 126         board_done_noalloc(&b2);
 127         return result;
 128 }