board.h

   1 /* probdist.h must be included before the include goard since we require
   2  * proper including order. */
   3 #include "probdist.h"
   4
   5 #ifndef ZZGO_BOARD_H
   6 #define ZZGO_BOARD_H
   7
   8 #include <inttypes.h>
   9 #include <stdbool.h>
  10 #include <stdint.h>
  11
  12 #include "util.h"
  13 #include "stone.h"
  14 #include "move.h"
  15
  16 struct features_gamma;
  17
  18
  19 /* The board implementation has bunch of optional features.
  20  * Turn them on below: */
  21
  22 #define WANT_BOARD_C // capturable groups queue
  23
  24 //#define BOARD_SIZE 9 // constant board size, allows better optimization
  25
  26 //#define BOARD_SPATHASH // incremental patternsp.h hashes
  27 #define BOARD_SPATHASH_MAXD 3 // maximal diameter
  28
  29 #define BOARD_PAT3 // incremental 3x3 pattern codes
  30
  31 //#define BOARD_TRAITS 1 // incremental point traits (see struct btraits)
  32 //#define BOARD_GAMMA 1 // incremental probability distribution (requires BOARD_TRAITS, BOARD_PAT3)
  33
  34
  35 /* Some engines might normalize their reading and skip symmetrical
  36  * moves. We will tell them how can they do it. */
  37 struct board_symmetry {
  38         /* Playground is in this rectangle. */
  39         int x1, x2, y1, y2;
  40         /* d ==  0: Full rectangle
  41          * d ==  1: Top triangle */
  42         int d;
  43         /* General symmetry type. */
  44         /* Note that the above is redundant to this, but just provided
  45          * for easier usage. */
  46         enum {
  47                 SYM_FULL,
  48                 SYM_DIAG_UP,
  49                 SYM_DIAG_DOWN,
  50                 SYM_HORIZ,
  51                 SYM_VERT,
  52                 SYM_NONE
  53         } type;
  54 };
  55
  56
  57 typedef uint64_t hash_t;
  58 #define PRIhash PRIx64
  59
  60
  61 /* Note that "group" is only chain of stones that is solidly
  62  * connected for us. */
  63 typedef coord_t group_t;
  64
  65 struct group {
  66         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  67          * don't care. */
  68         /* _Combination_ of these two values can make some difference
  69          * in performance - fine-tune. */
  70 #define GROUP_KEEP_LIBS 10
  71         // refill lib[] only when we hit this; this must be at least 2!
  72         // Moggy requires at least 3 - see below for semantic impact.
  73 #define GROUP_REFILL_LIBS 5
  74         coord_t lib[GROUP_KEEP_LIBS];
  75         /* libs is only LOWER BOUND for the number of real liberties!!!
  76          * It denotes only number of items in lib[], thus you can rely
  77          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  78         int libs;
  79 };
  80
  81 struct neighbor_colors {
  82         char colors[S_MAX];
  83 };
  84
  85
  86 /* Point traits bitmap; we update this information incrementally,
  87  * it can be used e.g. for fast pattern.h features matching. */
  88 struct btraits {
  89         /* Number of neighbors we can capture. 0=this move is
  90          * not capturing, 1..4=this many neighbors we can capture
  91          * (can be multiple neighbors of same group). */
  92         unsigned cap:3;
  93         /* Whether it is SAFE to play here. This is essentially just
  94          * cached result of board_safe_to_play(). (Of course the concept
  95          * of "safety" is not perfect here, but it's the cheapest
  96          * reasonable thing we can do.) */
  97         bool safe:1;
  98         /* Whether we need to re-compute this coordinate; used to
  99          * weed out duplicates. Maintained only for S_BLACK. */
 100         bool dirty:1;
 101 };
 102
 103
 104 /* You should treat this struct as read-only. Always call functions below if
 105  * you want to change it. */
 106
 107 struct board {
 108         int size; /* Including S_OFFBOARD margin - see below. */
 109         int size2; /* size^2 */
 110         int bits2; /* ceiling(log2(size2)) */
 111         int captures[S_MAX];
 112         float komi;
 113         int handicap;
 114         /* The ruleset is currently almost never taken into account;
 115          * the board implementation is basically Chinese rules (handicap
 116          * stones compensation) w/ suicide (or you can look at it as
 117          * New Zealand w/o handi stones compensation), while the engine
 118          * enforces no-suicide, making for real Chinese rules. */
 119         enum {
 120                 RULES_CHINESE, /* default value */
 121                 RULES_AGA,
 122                 RULES_NEW_ZEALAND,
 123                 RULES_JAPANESE,
 124         } rules;
 125
 126         /* Iterator offsets for foreach_neighbor*() */
 127         int nei8[8], dnei[4];
 128
 129         int moves;
 130         struct move last_move;
 131         struct move last_move2; /* second-to-last move */
 132         /* Whether we tried to add a hash twice; board_play*() can
 133          * set this, but it will still carry out the move as well! */
 134         bool superko_violation;
 135
 136         /* The following two structures are goban maps and are indexed by
 137          * coord.pos. The map is surrounded by a one-point margin from
 138          * S_OFFBOARD stones in order to speed up some internal loops.
 139          * Some of the foreach iterators below might include these points;
 140          * you need to handle them yourselves, if you need to. */
 141
 142         /* Stones played on the board */
 143         enum stone *b; /* enum stone */
 144         /* Group id the stones are part of; 0 == no group */
 145         group_t *g;
 146         /* Positions of next stones in the stone group; 0 == last stone */
 147         coord_t *p;
 148         /* Neighboring colors; numbers of neighbors of index color */
 149         struct neighbor_colors *n;
 150         /* Zobrist hash for each position */
 151         hash_t *h;
 152 #ifdef BOARD_SPATHASH
 153         /* For spatial hashes, we use only 24 bits. */
 154         /* [0] is d==1, we don't keep hash for d==0. */
 155         /* We keep hashes for black-to-play ([][0]) and white-to-play
 156          * ([][1], reversed stone colors since we match all patterns as
 157          * black-to-play). */
 158         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 159 #endif
 160 #ifdef BOARD_PAT3
 161         /* 3x3 pattern code for each position; see pattern3.h for encoding
 162          * specification. The information is only valid for empty points. */
 163         uint16_t *pat3;
 164 #endif
 165 #ifdef BOARD_TRAITS
 166         /* Incrementally matched point traits information, black-to-play
 167          * ([][0]) and white-to-play ([][1]). */
 168         /* The information is only valid for empty points. */
 169         struct btraits (*t)[2];
 170 #endif
 171 #ifdef BOARD_GAMMA
 172         /* Relative probabilities of moves being played next, computed by
 173          * multiplying gammas of the appropriate pattern features based on
 174          * pat3 and traits (see pattern.h). The probability distribution
 175          * is maintained over the full board grid. */
 176         /* - Always invalid moves are guaranteed to have zero probability.
 177          * - Self-eye-filling moves will always have zero probability.
 178          * - Ko-prohibited moves might have non-zero probability.
 179          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 180         struct probdist prob[2];
 181 #endif
 182         /* Cached information on x-y coordinates so that we avoid division. */
 183         uint8_t (*coord)[2];
 184
 185         /* Group information - indexed by gid (which is coord of base group stone) */
 186         struct group *gi;
 187
 188         /* Positions of free positions - queue (not map) */
 189         /* Note that free position here is any valid move; including single-point eyes!
 190          * However, pass is not included. */
 191         coord_t *f; int flen;
 192
 193 #ifdef WANT_BOARD_C
 194         /* Queue of capturable groups */
 195         group_t *c; int clen;
 196 #endif
 197
 198 #ifdef BOARD_TRAITS
 199         /* Queue of positions that need their traits updated */
 200         coord_t *tq; int tqlen;
 201 #endif
 202
 203         /* Symmetry information */
 204         struct board_symmetry symmetry;
 205
 206         /* Last ko played on the board. */
 207         struct move last_ko;
 208         int last_ko_age;
 209
 210         /* Basic ko check */
 211         struct move ko;
 212
 213         /* Engine-specific state; persistent through board development,
 214          * is reset only at clear_board. */
 215         void *es;
 216
 217         /* Playout-specific state; persistent through board development,
 218          * but its lifetime is maintained in play_random_game(); it should
 219          * not be set outside of it. */
 220         void *ps;
 221
 222 #ifdef BOARD_GAMMA
 223         /* Gamma values for probability distribution; user must setup
 224          * this pointer before any move is played, using board_gamma_set(). */
 225         struct features_gamma *gamma;
 226         /* Whether to compute the 'safe' trait using board_safe_to_play()
 227          * (false) or is_bad_selfatari() (true, much slower). */
 228         bool precise_selfatari;
 229 #endif
 230
 231
 232         /* --- PRIVATE DATA --- */
 233
 234         /* For superko check: */
 235
 236         /* Board "history" - hashes encountered. Size of the hash should be
 237          * >> board_size^2. */
 238 #define history_hash_bits 12
 239 #define history_hash_mask ((1 << history_hash_bits) - 1)
 240 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 241 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 242         hash_t history_hash[1 << history_hash_bits];
 243         /* Hash of current board position. */
 244         hash_t hash;
 245 };
 246
 247 #ifdef BOARD_SIZE
 248 /* Avoid unused variable warnings */
 249 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 250 #define board_size2(b_) (board_size(b_) * board_size(b_))
 251 #else
 252 #define board_size(b_) ((b_)->size)
 253 #define board_size2(b_) ((b_)->size2)
 254 #endif
 255
 256 #if BOARD_SIZE == 19
 257 #  define board_bits2(b_) 9
 258 #elif BOARD_SIZE == 13
 259 #  define board_bits2(b_) 8
 260 #elif BOARD_SIZE == 9
 261 #  define board_bits2(b_) 7
 262 #else
 263 #  define board_bits2(b_) ((b_)->bits2)
 264 #endif
 265
 266 #define board_at(b_, c) ((b_)->b[c])
 267 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 268
 269 #define group_at(b_, c) ((b_)->g[c])
 270 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 271
 272 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 273 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 274 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 275 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 276 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 277 #define immediate_liberty_count(b_, coord) (4 - neighbor_count_at(b_, coord, S_BLACK) - neighbor_count_at(b_, coord, S_WHITE) - neighbor_count_at(b_, coord, S_OFFBOARD))
 278
 279 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 280
 281 #define groupnext_at(b_, c) ((b_)->p[c])
 282 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 283
 284 #define group_base(g_) (g_)
 285 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 286 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 287 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 288
 289 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 290
 291 struct board *board_init(void);
 292 struct board *board_copy(struct board *board2, struct board *board1);
 293 void board_done_noalloc(struct board *board);
 294 void board_done(struct board *board);
 295 /* size here is without the S_OFFBOARD margin. */
 296 void board_resize(struct board *board, int size);
 297 void board_clear(struct board *board);
 298
 299 struct FILE;
 300 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 301 void board_print(struct board *board, FILE *f);
 302 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 303
 304 /* Place given handicap on the board; coordinates are printed to f. */
 305 void board_handicap(struct board *board, int stones, FILE *f);
 306
 307 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 308 int board_play(struct board *board, struct move *m);
 309 /* Like above, but plays random move; the move coordinate is recorded
 310  * to *coord. This method will never fill your own eye. pass is played
 311  * when no move can be played. You can impose extra restrictions if you
 312  * supply your own permit function; the permit function can also modify
 313  * the move coordinate to redirect the move elsewhere. */
 314 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 315 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 316
 317 /* Returns true if given move can be played. */
 318 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 319 static bool board_is_valid_move(struct board *b, struct move *m);
 320 /* Returns true if ko was just taken. */
 321 static bool board_playing_ko_threat(struct board *b);
 322 /* Returns 0 or ID of neighboring group in atari. */
 323 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 324 /* Returns true if the move is not obvious self-atari. */
 325 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 326
 327 /* Adjust symmetry information as if given coordinate has been played. */
 328 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 329 /* Associate a set of feature gamma values (for pd building) with the board. */
 330 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 331 /* Force re-compute of a probability distribution item. */
 332 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 333
 334 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 335 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 336 /* Returns true if given coordinate could be a false eye; this check makes
 337  * sense only if you already know the coordinate is_eyelike(). */
 338 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 339 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 340  * at least tries to). */
 341 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 342 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 343 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 344
 345 /* board_official_score() is the scoring method for yielding score suitable
 346  * for external presentation. For fast scoring of entirely filled boards
 347  * (e.g. playouts), use board_fast_score(). */
 348 /* Positive: W wins */
 349 /* Compare number of stones + 1pt eyes. */
 350 float board_fast_score(struct board *board);
 351 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 352 struct move_queue;
 353 float board_official_score(struct board *board, struct move_queue *mq);
 354
 355 /** Iterators */
 356
 357 #define foreach_point(board_) \
 358         do { \
 359                 coord_t c = 0; \
 360                 for (; c < board_size(board_) * board_size(board_); c++)
 361 #define foreach_point_and_pass(board_) \
 362         do { \
 363                 coord_t c = pass; \
 364                 for (; c < board_size(board_) * board_size(board_); c++)
 365 #define foreach_point_end \
 366         } while (0)
 367
 368 #define foreach_in_group(board_, group_) \
 369         do { \
 370                 struct board *board__ = board_; \
 371                 coord_t c = group_base(group_); \
 372                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 373                 do {
 374 #define foreach_in_group_end \
 375                         c = c2; c2 = groupnext_at(board__, c2); \
 376                 } while (c != 0); \
 377         } while (0)
 378
 379 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 380  * on S_OFFBOARD coordinates. */
 381 #define foreach_neighbor(board_, coord_, loop_body) \
 382         do { \
 383                 struct board *board__ = board_; \
 384                 coord_t coord__ = coord_; \
 385                 coord_t c; \
 386                 c = coord__ - 1; do { loop_body } while (0); \
 387                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 388                 c = coord__ + 1; do { loop_body } while (0); \
 389                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 390         } while (0)
 391
 392 #define foreach_8neighbor(board_, coord_) \
 393         do { \
 394                 int fn__i; \
 395                 coord_t c = (coord_); \
 396                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 397                         c += (board_)->nei8[fn__i];
 398 #define foreach_8neighbor_end \
 399                 } \
 400         } while (0)
 401
 402 #define foreach_diag_neighbor(board_, coord_) \
 403         do { \
 404                 int fn__i; \
 405                 coord_t c = (coord_); \
 406                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 407                         c += (board_)->dnei[fn__i];
 408 #define foreach_diag_neighbor_end \
 409                 } \
 410         } while (0)
 411
 412
 413 static inline bool
 414 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 415 {
 416         return (neighbor_count_at(board, coord, eye_color)
 417                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 418 }
 419
 420 static inline bool
 421 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 422 {
 423         if (board_at(board, coord) != S_NONE)
 424                 return false;
 425         if (!board_is_eyelike(board, coord, stone_other(color)))
 426                 return true;
 427         /* Play within {true,false} eye-ish formation */
 428         if (board->ko.coord == coord && board->ko.color == color)
 429                 return false;
 430 #ifdef BOARD_TRAITS
 431         /* XXX: Disallows suicide. */
 432         return trait_at(board, coord, color).cap > 0;
 433 #else
 434         int groups_in_atari = 0;
 435         foreach_neighbor(board, coord, {
 436                 group_t g = group_at(board, c);
 437                 groups_in_atari += (board_group_info(board, g).libs == 1);
 438         });
 439         return !!groups_in_atari;
 440 #endif
 441 }
 442
 443 static inline bool
 444 board_is_valid_move(struct board *board, struct move *m)
 445 {
 446         return board_is_valid_play(board, m->color, m->coord);
 447 }
 448
 449 static inline bool
 450 board_playing_ko_threat(struct board *b)
 451 {
 452         return !is_pass(b->ko.coord);
 453 }
 454
 455 static inline group_t
 456 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 457 {
 458 #ifdef BOARD_TRAITS
 459         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 460 #endif
 461         foreach_neighbor(b, coord, {
 462                 group_t g = group_at(b, c);
 463                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 464                         return g;
 465                 /* We return first match. */
 466         });
 467         return 0;
 468 }
 469
 470 static inline bool
 471 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 472 {
 473         /* number of free neighbors */
 474         int libs = immediate_liberty_count(b, coord);
 475         if (libs > 1)
 476                 return true;
 477
 478 #ifdef BOARD_TRAITS
 479         /* number of capturable enemy groups */
 480         if (trait_at(b, coord, color).cap > 0)
 481                 return true; // XXX: We don't account for snapback.
 482         /* number of non-capturable friendly groups */
 483         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 484         if (noncap_ours < 1)
 485                 return false;
 486 /*#else see below */
 487 #endif
 488
 489         /* ok, but we need to check if they don't have just two libs. */
 490         coord_t onelib = -1;
 491         foreach_neighbor(b, coord, {
 492 #ifndef BOARD_TRAITS
 493                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 494                         return true; // can capture; no snapback check
 495 #endif
 496                 if (board_at(b, c) != color) continue;
 497                 group_t g = group_at(b, c);
 498                 if (board_group_info(b, g).libs == 1) continue; // in atari
 499                 if (board_group_info(b, g).libs == 2) { // two liberties
 500                         if (libs > 0) return true; // we already have one real liberty
 501                         // get the other liberty
 502                         coord_t lib = board_group_info(b, g).lib[0];
 503                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 504                         /* we might be connecting two 2-lib groups, which is ok;
 505                          * so remember the other liberty and just make sure it's
 506                          * not the same one */
 507                         if (onelib >= 0 && lib != onelib) return true;
 508                         onelib = lib;
 509                         continue;
 510                 }
 511                 // many liberties
 512                 return true;
 513         });
 514         // no good support group
 515         return false;
 516 }
 517
 518 #endif