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 /* XXX: This really belongs in pattern3.h, unfortunately that would mean
  61  * a dependency hell. */
  62 typedef uint16_t hash3_t; // 3x3 pattern hash
  63
  64
  65 /* Note that "group" is only chain of stones that is solidly
  66  * connected for us. */
  67 typedef coord_t group_t;
  68
  69 struct group {
  70         /* We keep track of only up to GROUP_KEEP_LIBS; over that, we
  71          * don't care. */
  72         /* _Combination_ of these two values can make some difference
  73          * in performance - fine-tune. */
  74 #define GROUP_KEEP_LIBS 10
  75         // refill lib[] only when we hit this; this must be at least 2!
  76         // Moggy requires at least 3 - see below for semantic impact.
  77 #define GROUP_REFILL_LIBS 5
  78         coord_t lib[GROUP_KEEP_LIBS];
  79         /* libs is only LOWER BOUND for the number of real liberties!!!
  80          * It denotes only number of items in lib[], thus you can rely
  81          * on it to store real liberties only up to <= GROUP_REFILL_LIBS. */
  82         int libs;
  83 };
  84
  85 struct neighbor_colors {
  86         char colors[S_MAX];
  87 };
  88
  89
  90 /* Point traits bitmap; we update this information incrementally,
  91  * it can be used e.g. for fast pattern.h features matching. */
  92 struct btraits {
  93         /* Number of neighbors we can capture. 0=this move is
  94          * not capturing, 1..4=this many neighbors we can capture
  95          * (can be multiple neighbors of same group). */
  96         unsigned cap:3;
  97         /* Whether it is SAFE to play here. This is essentially just
  98          * cached result of board_safe_to_play(). (Of course the concept
  99          * of "safety" is not perfect here, but it's the cheapest
 100          * reasonable thing we can do.) */
 101         bool safe:1;
 102         /* Whether we need to re-compute this coordinate; used to
 103          * weed out duplicates. Maintained only for S_BLACK. */
 104         bool dirty:1;
 105 };
 106
 107
 108 /* You should treat this struct as read-only. Always call functions below if
 109  * you want to change it. */
 110
 111 struct board {
 112         int size; /* Including S_OFFBOARD margin - see below. */
 113         int size2; /* size^2 */
 114         int bits2; /* ceiling(log2(size2)) */
 115         int captures[S_MAX];
 116         float komi;
 117         int handicap;
 118         /* The ruleset is currently almost never taken into account;
 119          * the board implementation is basically Chinese rules (handicap
 120          * stones compensation) w/ suicide (or you can look at it as
 121          * New Zealand w/o handi stones compensation), while the engine
 122          * enforces no-suicide, making for real Chinese rules. */
 123         enum {
 124                 RULES_CHINESE, /* default value */
 125                 RULES_AGA,
 126                 RULES_NEW_ZEALAND,
 127                 RULES_JAPANESE,
 128         } rules;
 129
 130         /* Iterator offsets for foreach_neighbor*() */
 131         int nei8[8], dnei[4];
 132
 133         int moves;
 134         struct move last_move;
 135         struct move last_move2; /* second-to-last move */
 136         /* Whether we tried to add a hash twice; board_play*() can
 137          * set this, but it will still carry out the move as well! */
 138         bool superko_violation;
 139
 140         /* The following two structures are goban maps and are indexed by
 141          * coord.pos. The map is surrounded by a one-point margin from
 142          * S_OFFBOARD stones in order to speed up some internal loops.
 143          * Some of the foreach iterators below might include these points;
 144          * you need to handle them yourselves, if you need to. */
 145
 146         /* Stones played on the board */
 147         enum stone *b; /* enum stone */
 148         /* Group id the stones are part of; 0 == no group */
 149         group_t *g;
 150         /* Positions of next stones in the stone group; 0 == last stone */
 151         coord_t *p;
 152         /* Neighboring colors; numbers of neighbors of index color */
 153         struct neighbor_colors *n;
 154         /* Zobrist hash for each position */
 155         hash_t *h;
 156 #ifdef BOARD_SPATHASH
 157         /* For spatial hashes, we use only 24 bits. */
 158         /* [0] is d==1, we don't keep hash for d==0. */
 159         /* We keep hashes for black-to-play ([][0]) and white-to-play
 160          * ([][1], reversed stone colors since we match all patterns as
 161          * black-to-play). */
 162         uint32_t (*spathash)[BOARD_SPATHASH_MAXD][2];
 163 #endif
 164 #ifdef BOARD_PAT3
 165         /* 3x3 pattern code for each position; see pattern3.h for encoding
 166          * specification. The information is only valid for empty points. */
 167         hash3_t *pat3;
 168 #endif
 169 #ifdef BOARD_TRAITS
 170         /* Incrementally matched point traits information, black-to-play
 171          * ([][0]) and white-to-play ([][1]). */
 172         /* The information is only valid for empty points. */
 173         struct btraits (*t)[2];
 174 #endif
 175 #ifdef BOARD_GAMMA
 176         /* Relative probabilities of moves being played next, computed by
 177          * multiplying gammas of the appropriate pattern features based on
 178          * pat3 and traits (see pattern.h). The probability distribution
 179          * is maintained over the full board grid. */
 180         /* - Always invalid moves are guaranteed to have zero probability.
 181          * - Self-eye-filling moves will always have zero probability.
 182          * - Ko-prohibited moves might have non-zero probability.
 183          * - FEAT_CONTIGUITY is not accounted for in the probability. */
 184         struct probdist prob[2];
 185 #endif
 186         /* Cached information on x-y coordinates so that we avoid division. */
 187         uint8_t (*coord)[2];
 188
 189         /* Group information - indexed by gid (which is coord of base group stone) */
 190         struct group *gi;
 191
 192         /* Positions of free positions - queue (not map) */
 193         /* Note that free position here is any valid move; including single-point eyes!
 194          * However, pass is not included. */
 195         coord_t *f; int flen;
 196
 197 #ifdef WANT_BOARD_C
 198         /* Queue of capturable groups */
 199         group_t *c; int clen;
 200 #endif
 201
 202 #ifdef BOARD_TRAITS
 203         /* Queue of positions that need their traits updated */
 204         coord_t *tq; int tqlen;
 205 #endif
 206
 207         /* Symmetry information */
 208         struct board_symmetry symmetry;
 209
 210         /* Last ko played on the board. */
 211         struct move last_ko;
 212         int last_ko_age;
 213
 214         /* Basic ko check */
 215         struct move ko;
 216
 217         /* Engine-specific state; persistent through board development,
 218          * is reset only at clear_board. */
 219         void *es;
 220
 221         /* Playout-specific state; persistent through board development,
 222          * but its lifetime is maintained in play_random_game(); it should
 223          * not be set outside of it. */
 224         void *ps;
 225
 226 #ifdef BOARD_GAMMA
 227         /* Gamma values for probability distribution; user must setup
 228          * this pointer before any move is played, using board_gamma_set(). */
 229         struct features_gamma *gamma;
 230         /* Whether to compute the 'safe' trait using board_safe_to_play()
 231          * (false) or is_bad_selfatari() (true, much slower). */
 232         bool precise_selfatari;
 233 #endif
 234
 235
 236         /* --- PRIVATE DATA --- */
 237
 238         /* For superko check: */
 239
 240         /* Board "history" - hashes encountered. Size of the hash should be
 241          * >> board_size^2. */
 242 #define history_hash_bits 12
 243 #define history_hash_mask ((1 << history_hash_bits) - 1)
 244 #define history_hash_prev(i) ((i - 1) & history_hash_mask)
 245 #define history_hash_next(i) ((i + 1) & history_hash_mask)
 246         hash_t history_hash[1 << history_hash_bits];
 247         /* Hash of current board position. */
 248         hash_t hash;
 249 };
 250
 251 #ifdef BOARD_SIZE
 252 /* Avoid unused variable warnings */
 253 #define board_size(b_) (((b_) == (b_)) ? BOARD_SIZE + 2 : 0)
 254 #define board_size2(b_) (board_size(b_) * board_size(b_))
 255 #else
 256 #define board_size(b_) ((b_)->size)
 257 #define board_size2(b_) ((b_)->size2)
 258 #endif
 259
 260 #if BOARD_SIZE == 19
 261 #  define board_bits2(b_) 9
 262 #elif BOARD_SIZE == 13
 263 #  define board_bits2(b_) 8
 264 #elif BOARD_SIZE == 9
 265 #  define board_bits2(b_) 7
 266 #else
 267 #  define board_bits2(b_) ((b_)->bits2)
 268 #endif
 269
 270 #define board_at(b_, c) ((b_)->b[c])
 271 #define board_atxy(b_, x, y) ((b_)->b[(x) + board_size(b_) * (y)])
 272
 273 #define group_at(b_, c) ((b_)->g[c])
 274 #define group_atxy(b_, x, y) ((b_)->g[(x) + board_size(b_) * (y)])
 275
 276 /* Warning! Neighbor count is kept up-to-date for S_NONE! */
 277 #define neighbor_count_at(b_, coord, color) ((b_)->n[coord].colors[(enum stone) color])
 278 #define set_neighbor_count_at(b_, coord, color, count) (neighbor_count_at(b_, coord, color) = (count))
 279 #define inc_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)++)
 280 #define dec_neighbor_count_at(b_, coord, color) (neighbor_count_at(b_, coord, color)--)
 281 #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))
 282
 283 #define trait_at(b_, coord, color) (b_)->t[coord][(color) - 1]
 284
 285 #define groupnext_at(b_, c) ((b_)->p[c])
 286 #define groupnext_atxy(b_, x, y) ((b_)->p[(x) + board_size(b_) * (y)])
 287
 288 #define group_base(g_) (g_)
 289 #define board_group_info(b_, g_) ((b_)->gi[(g_)])
 290 #define board_group_captured(b_, g_) (board_group_info(b_, g_).libs == 0)
 291 #define group_is_onestone(b_, g_) (groupnext_at(b_, group_base(g_)) == 0)
 292
 293 #define hash_at(b_, coord, color) ((b_)->h[((color) == S_BLACK ? board_size2(b_) : 0) + coord])
 294
 295 struct board *board_init(void);
 296 struct board *board_copy(struct board *board2, struct board *board1);
 297 void board_done_noalloc(struct board *board);
 298 void board_done(struct board *board);
 299 /* size here is without the S_OFFBOARD margin. */
 300 void board_resize(struct board *board, int size);
 301 void board_clear(struct board *board);
 302
 303 struct FILE;
 304 typedef char *(*board_cprint)(struct board *b, coord_t c, char *s, char *end);
 305 void board_print(struct board *board, FILE *f);
 306 void board_print_custom(struct board *board, FILE *f, board_cprint cprint);
 307
 308 /* Place given handicap on the board; coordinates are printed to f. */
 309 void board_handicap(struct board *board, int stones, FILE *f);
 310
 311 /* Returns group id, 0 on allowed suicide, pass or resign, -1 on error */
 312 int board_play(struct board *board, struct move *m);
 313 /* Like above, but plays random move; the move coordinate is recorded
 314  * to *coord. This method will never fill your own eye. pass is played
 315  * when no move can be played. You can impose extra restrictions if you
 316  * supply your own permit function; the permit function can also modify
 317  * the move coordinate to redirect the move elsewhere. */
 318 typedef bool (*ppr_permit)(void *data, struct board *b, struct move *m);
 319 void board_play_random(struct board *b, enum stone color, coord_t *coord, ppr_permit permit, void *permit_data);
 320
 321 /* Returns true if given move can be played. */
 322 static bool board_is_valid_play(struct board *b, enum stone color, coord_t coord);
 323 static bool board_is_valid_move(struct board *b, struct move *m);
 324 /* Returns true if ko was just taken. */
 325 static bool board_playing_ko_threat(struct board *b);
 326 /* Returns 0 or ID of neighboring group in atari. */
 327 static group_t board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color);
 328 /* Returns true if the move is not obvious self-atari. */
 329 static bool board_safe_to_play(struct board *b, coord_t coord, enum stone color);
 330
 331 /* Adjust symmetry information as if given coordinate has been played. */
 332 void board_symmetry_update(struct board *b, struct board_symmetry *symmetry, coord_t c);
 333 /* Associate a set of feature gamma values (for pd building) with the board. */
 334 void board_gamma_set(struct board *b, struct features_gamma *gamma, bool precise_selfatari);
 335 /* Force re-compute of a probability distribution item. */
 336 void board_gamma_update(struct board *b, coord_t coord, enum stone color);
 337
 338 /* Returns true if given coordinate has all neighbors of given color or the edge. */
 339 static bool board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 340 /* Returns true if given coordinate could be a false eye; this check makes
 341  * sense only if you already know the coordinate is_eyelike(). */
 342 bool board_is_false_eyelike(struct board *board, coord_t coord, enum stone eye_color);
 343 /* Returns true if given coordinate is a 1-pt eye (checks against false eyes, or
 344  * at least tries to). */
 345 bool board_is_one_point_eye(struct board *board, coord_t c, enum stone eye_color);
 346 /* Returns color of a 1pt eye owner, S_NONE if not an eye. */
 347 enum stone board_get_one_point_eye(struct board *board, coord_t c);
 348
 349 /* board_official_score() is the scoring method for yielding score suitable
 350  * for external presentation. For fast scoring of entirely filled boards
 351  * (e.g. playouts), use board_fast_score(). */
 352 /* Positive: W wins */
 353 /* Compare number of stones + 1pt eyes. */
 354 float board_fast_score(struct board *board);
 355 /* Tromp-Taylor scoring, assuming given groups are actually dead. */
 356 struct move_queue;
 357 float board_official_score(struct board *board, struct move_queue *mq);
 358
 359 /** Iterators */
 360
 361 #define foreach_point(board_) \
 362         do { \
 363                 coord_t c = 0; \
 364                 for (; c < board_size(board_) * board_size(board_); c++)
 365 #define foreach_point_and_pass(board_) \
 366         do { \
 367                 coord_t c = pass; \
 368                 for (; c < board_size(board_) * board_size(board_); c++)
 369 #define foreach_point_end \
 370         } while (0)
 371
 372 #define foreach_in_group(board_, group_) \
 373         do { \
 374                 struct board *board__ = board_; \
 375                 coord_t c = group_base(group_); \
 376                 coord_t c2 = c; c2 = groupnext_at(board__, c2); \
 377                 do {
 378 #define foreach_in_group_end \
 379                         c = c2; c2 = groupnext_at(board__, c2); \
 380                 } while (c != 0); \
 381         } while (0)
 382
 383 /* NOT VALID inside of foreach_point() or another foreach_neighbor(), or rather
 384  * on S_OFFBOARD coordinates. */
 385 #define foreach_neighbor(board_, coord_, loop_body) \
 386         do { \
 387                 struct board *board__ = board_; \
 388                 coord_t coord__ = coord_; \
 389                 coord_t c; \
 390                 c = coord__ - 1; do { loop_body } while (0); \
 391                 c = coord__ - board_size(board__); do { loop_body } while (0); \
 392                 c = coord__ + 1; do { loop_body } while (0); \
 393                 c = coord__ + board_size(board__); do { loop_body } while (0); \
 394         } while (0)
 395
 396 #define foreach_8neighbor(board_, coord_) \
 397         do { \
 398                 int fn__i; \
 399                 coord_t c = (coord_); \
 400                 for (fn__i = 0; fn__i < 8; fn__i++) { \
 401                         c += (board_)->nei8[fn__i];
 402 #define foreach_8neighbor_end \
 403                 } \
 404         } while (0)
 405
 406 #define foreach_diag_neighbor(board_, coord_) \
 407         do { \
 408                 int fn__i; \
 409                 coord_t c = (coord_); \
 410                 for (fn__i = 0; fn__i < 4; fn__i++) { \
 411                         c += (board_)->dnei[fn__i];
 412 #define foreach_diag_neighbor_end \
 413                 } \
 414         } while (0)
 415
 416
 417 static inline bool
 418 board_is_eyelike(struct board *board, coord_t coord, enum stone eye_color)
 419 {
 420         return (neighbor_count_at(board, coord, eye_color)
 421                 + neighbor_count_at(board, coord, S_OFFBOARD)) == 4;
 422 }
 423
 424 static inline bool
 425 board_is_valid_play(struct board *board, enum stone color, coord_t coord)
 426 {
 427         if (board_at(board, coord) != S_NONE)
 428                 return false;
 429         if (!board_is_eyelike(board, coord, stone_other(color)))
 430                 return true;
 431         /* Play within {true,false} eye-ish formation */
 432         if (board->ko.coord == coord && board->ko.color == color)
 433                 return false;
 434 #ifdef BOARD_TRAITS
 435         /* XXX: Disallows suicide. */
 436         return trait_at(board, coord, color).cap > 0;
 437 #else
 438         int groups_in_atari = 0;
 439         foreach_neighbor(board, coord, {
 440                 group_t g = group_at(board, c);
 441                 groups_in_atari += (board_group_info(board, g).libs == 1);
 442         });
 443         return !!groups_in_atari;
 444 #endif
 445 }
 446
 447 static inline bool
 448 board_is_valid_move(struct board *board, struct move *m)
 449 {
 450         return board_is_valid_play(board, m->color, m->coord);
 451 }
 452
 453 static inline bool
 454 board_playing_ko_threat(struct board *b)
 455 {
 456         return !is_pass(b->ko.coord);
 457 }
 458
 459 static inline group_t
 460 board_get_atari_neighbor(struct board *b, coord_t coord, enum stone group_color)
 461 {
 462 #ifdef BOARD_TRAITS
 463         if (!trait_at(b, coord, stone_other(group_color)).cap) return 0;
 464 #endif
 465         foreach_neighbor(b, coord, {
 466                 group_t g = group_at(b, c);
 467                 if (g && board_at(b, c) == group_color && board_group_info(b, g).libs == 1)
 468                         return g;
 469                 /* We return first match. */
 470         });
 471         return 0;
 472 }
 473
 474 static inline bool
 475 board_safe_to_play(struct board *b, coord_t coord, enum stone color)
 476 {
 477         /* number of free neighbors */
 478         int libs = immediate_liberty_count(b, coord);
 479         if (libs > 1)
 480                 return true;
 481
 482 #ifdef BOARD_TRAITS
 483         /* number of capturable enemy groups */
 484         if (trait_at(b, coord, color).cap > 0)
 485                 return true; // XXX: We don't account for snapback.
 486         /* number of non-capturable friendly groups */
 487         int noncap_ours = neighbor_count_at(b, coord, color) - trait_at(b, coord, stone_other(color)).cap;
 488         if (noncap_ours < 1)
 489                 return false;
 490 /*#else see below */
 491 #endif
 492
 493         /* ok, but we need to check if they don't have just two libs. */
 494         coord_t onelib = -1;
 495         foreach_neighbor(b, coord, {
 496 #ifndef BOARD_TRAITS
 497                 if (board_at(b, c) == stone_other(color) && board_group_info(b, group_at(b, c)).libs == 1)
 498                         return true; // can capture; no snapback check
 499 #endif
 500                 if (board_at(b, c) != color) continue;
 501                 group_t g = group_at(b, c);
 502                 if (board_group_info(b, g).libs == 1) continue; // in atari
 503                 if (board_group_info(b, g).libs == 2) { // two liberties
 504                         if (libs > 0) return true; // we already have one real liberty
 505                         // get the other liberty
 506                         coord_t lib = board_group_info(b, g).lib[0];
 507                         if (lib == coord) lib = board_group_info(b, g).lib[0];
 508                         /* we might be connecting two 2-lib groups, which is ok;
 509                          * so remember the other liberty and just make sure it's
 510                          * not the same one */
 511                         if (onelib >= 0 && lib != onelib) return true;
 512                         onelib = lib;
 513                         continue;
 514                 }
 515                 // many liberties
 516                 return true;
 517         });
 518         // no good support group
 519         return false;
 520 }
 521
 522 #endif