| 1 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\ |
| 2 | * This is GNU Go, a Go program. Contact gnugo@gnu.org, or see * |
| 3 | * http://www.gnu.org/software/gnugo/ for more information. * |
| 4 | * * |
| 5 | * Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, * |
| 6 | * 2008 and 2009 by the Free Software Foundation. * |
| 7 | * * |
| 8 | * This program is free software; you can redistribute it and/or * |
| 9 | * modify it under the terms of the GNU General Public License as * |
| 10 | * published by the Free Software Foundation - version 3 or * |
| 11 | * (at your option) any later version. * |
| 12 | * * |
| 13 | * This program is distributed in the hope that it will be useful, * |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| 16 | * GNU General Public License in file COPYING for more details. * |
| 17 | * * |
| 18 | * You should have received a copy of the GNU General Public * |
| 19 | * License along with this program; if not, write to the Free * |
| 20 | * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * |
| 21 | * Boston, MA 02111, USA. * |
| 22 | \* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 23 | |
| 24 | |
| 25 | /* This file contains functions that deals with threats and, |
| 26 | * especially, combinations of threats. |
| 27 | */ |
| 28 | |
| 29 | #include "gnugo.h" |
| 30 | |
| 31 | #include <string.h> |
| 32 | |
| 33 | #include "liberty.h" |
| 34 | #include "gg_utils.h" |
| 35 | #include "patterns.h" |
| 36 | |
| 37 | |
| 38 | static void find_double_threats(int color); |
| 39 | |
| 40 | /* Generate move reasons for combination attacks and defenses against |
| 41 | * them. |
| 42 | * |
| 43 | * This is one of the move generators called from genmove(). |
| 44 | */ |
| 45 | |
| 46 | void |
| 47 | combinations(int color) |
| 48 | { |
| 49 | int save_verbose; |
| 50 | int attack_point; |
| 51 | signed char defense_points[BOARDMAX]; |
| 52 | int other = OTHER_COLOR(color); |
| 53 | int aa_val; |
| 54 | |
| 55 | /* Find intersections with multiple threats. */ |
| 56 | find_double_threats(color); |
| 57 | |
| 58 | save_verbose = verbose; |
| 59 | if (verbose > 0) |
| 60 | verbose--; |
| 61 | |
| 62 | if (save_verbose) |
| 63 | gprintf("\nlooking for combination attacks ...\n"); |
| 64 | |
| 65 | aa_val = atari_atari(color, &attack_point, NULL, save_verbose); |
| 66 | if (aa_val > 0) { |
| 67 | if (save_verbose) |
| 68 | gprintf("Combination attack for %C with size %d found at %1m\n", |
| 69 | color, aa_val, attack_point); |
| 70 | add_my_atari_atari_move(attack_point, aa_val); |
| 71 | } |
| 72 | |
| 73 | aa_val = atari_atari(other, &attack_point, defense_points, save_verbose); |
| 74 | if (aa_val > 0) { |
| 75 | int pos; |
| 76 | if (save_verbose) |
| 77 | gprintf("Combination attack for %C with size %d found at %1m\n", |
| 78 | other, aa_val, attack_point); |
| 79 | |
| 80 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 81 | if (ON_BOARD(pos) && defense_points[pos]) { |
| 82 | add_your_atari_atari_move(pos, aa_val); |
| 83 | if (save_verbose) |
| 84 | gprintf("- defense at %1m\n", pos); |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | verbose = save_verbose; |
| 89 | } |
| 90 | |
| 91 | |
| 92 | #define MAX_THREATENED_STRINGS 10 /* Should be enough for one intersection */ |
| 93 | |
| 94 | static void |
| 95 | find_double_threats(int color) |
| 96 | { |
| 97 | int ii; |
| 98 | int k; |
| 99 | int l; |
| 100 | |
| 101 | for (ii = BOARDMIN; ii < BOARDMAX; ii++) { |
| 102 | int num_a_threatened_groups; |
| 103 | int a_threatened_groups[MAX_THREATENED_STRINGS]; |
| 104 | #if 0 |
| 105 | int num_d_threatened_groups; |
| 106 | int d_threatened_groups[MAX_THREATENED_STRINGS]; |
| 107 | #endif |
| 108 | |
| 109 | if (!ON_BOARD(ii)) |
| 110 | continue; |
| 111 | |
| 112 | /* Generate an EITHER_MOVE move reasons for each pair of the |
| 113 | * threatened strings. We must also remove the threats, because |
| 114 | * otherwise we would get followup points for them as well. |
| 115 | * |
| 116 | * FIXME: |
| 117 | * - This is perhaps not the best way to do it, but realistically |
| 118 | * it will be seldom that more than two strings are threatened |
| 119 | * at the same point. Still, we should find a better way. |
| 120 | * - EITHER_MOVE should be generalized to more than two strings. |
| 121 | */ |
| 122 | num_a_threatened_groups = get_attack_threats(ii, MAX_THREATENED_STRINGS, |
| 123 | a_threatened_groups); |
| 124 | if (num_a_threatened_groups > 1) { |
| 125 | if (trymove(ii, color, "find_double_threats-A", ii)) { |
| 126 | for (k = 0; k < num_a_threatened_groups - 1; ++k) |
| 127 | for (l = k + 1; l < num_a_threatened_groups; ++l) { |
| 128 | /* Note: If we used attack_either() here instead of trymove() |
| 129 | * and !defend_both(), we would not make use of the fact |
| 130 | * that we already know of a common threat point for |
| 131 | * the two strings. |
| 132 | * Besides, attack_either is currently (3.1.11) not very good. |
| 133 | * |
| 134 | * The call to attack() is intended to detect the case |
| 135 | * where the move at ii is a snapback capture. |
| 136 | */ |
| 137 | if (board[a_threatened_groups[k]] == EMPTY |
| 138 | || board[a_threatened_groups[l]] == EMPTY) { |
| 139 | if (!attack(ii, NULL)) { |
| 140 | TRACE("Double threat at %1m, either %1m or %1m attacked.\n", |
| 141 | ii, a_threatened_groups[k], a_threatened_groups[l]); |
| 142 | add_either_move(ii, ATTACK_STRING, a_threatened_groups[k], |
| 143 | ATTACK_STRING, a_threatened_groups[l]); |
| 144 | remove_attack_threat_move(ii, a_threatened_groups[k]); |
| 145 | remove_attack_threat_move(ii, a_threatened_groups[l]); |
| 146 | } |
| 147 | } |
| 148 | else if (!defend_both(a_threatened_groups[k], |
| 149 | a_threatened_groups[l])) { |
| 150 | TRACE("Double threat at %1m, either %1m or %1m attacked.\n", |
| 151 | ii, a_threatened_groups[k], a_threatened_groups[l]); |
| 152 | add_either_move(ii, ATTACK_STRING, a_threatened_groups[k], |
| 153 | ATTACK_STRING, a_threatened_groups[l]); |
| 154 | remove_attack_threat_move(ii, a_threatened_groups[k]); |
| 155 | remove_attack_threat_move(ii, a_threatened_groups[l]); |
| 156 | } |
| 157 | } |
| 158 | popgo(); |
| 159 | } |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | |
| 164 | /* FIXME: |
| 165 | * TODO: |
| 166 | * - defense threats |
| 167 | * - combinations of owl threats and other threats |
| 168 | * - combinations of threats to cut and connect |
| 169 | * - combinations of breakins into enemy territory |
| 170 | */ |
| 171 | } |
| 172 | |
| 173 | |
| 174 | /* ================================================================ */ |
| 175 | /* Combination attacks */ |
| 176 | /* ================================================================ */ |
| 177 | |
| 178 | |
| 179 | /* atari_atari(color, *move) looks for a series of ataris on |
| 180 | * strings of the other color culminating in the capture of |
| 181 | * a string which is thought to be invulnerable by the reading |
| 182 | * code. Such a move can be missed since it may be that each |
| 183 | * string involved individually can be rescued, but nevertheless |
| 184 | * one of them can be caught. The simplest example is a double |
| 185 | * atari. The return value is the size of the smallest opponent |
| 186 | * worm. |
| 187 | * |
| 188 | * One danger with this scheme is that the first atari |
| 189 | * tried might be irrelevant to the actual combination. |
| 190 | * To detect this possibility, once we've found a combination, |
| 191 | * we mark that first move as forbidden, then try again. If |
| 192 | * no combination of the same size or larger turns up, then |
| 193 | * the first move was indeed essential. |
| 194 | * |
| 195 | * For the purpose of the move generation, returns the |
| 196 | * size of the smallest of the worms under attack. |
| 197 | */ |
| 198 | |
| 199 | /* Local struct to keep track of atari_atari attack moves and what |
| 200 | * they threat. |
| 201 | */ |
| 202 | #define AA_MAX_TARGETS_PER_MOVE 4 |
| 203 | |
| 204 | #define MAX_AA_DIST 5 |
| 205 | |
| 206 | struct aa_move { |
| 207 | int move; |
| 208 | int target[AA_MAX_TARGETS_PER_MOVE]; |
| 209 | }; |
| 210 | |
| 211 | #define AA_MAX_MOVES MAX_BOARD * MAX_BOARD |
| 212 | static int aa_status[BOARDMAX]; /* ALIVE, DEAD or CRITICAL */ |
| 213 | static int forbidden[BOARDMAX]; |
| 214 | static int aa_values[BOARDMAX]; |
| 215 | static void compute_aa_status(int color, |
| 216 | const signed char safe_stones[BOARDMAX]); |
| 217 | static void compute_aa_values(int color); |
| 218 | static int get_aa_status(int pos); |
| 219 | static int do_atari_atari(int color, int *attack_point, int *defense_point, |
| 220 | signed char all_potential_defenses[BOARDMAX], |
| 221 | int last_friendly, int save_verbose, int minsize, |
| 222 | signed char goal[BOARDMAX]); |
| 223 | static int atari_atari_succeeded(int color, int *attack_point, |
| 224 | int *defense_point, int last_friendly, |
| 225 | int save_verbose, int minsize); |
| 226 | static void atari_atari_find_attack_moves(int color, int minsize, |
| 227 | struct aa_move attacks[AA_MAX_MOVES], |
| 228 | signed char goal[BOARDMAX]); |
| 229 | static void atari_atari_attack_patterns(int color, int minsize, |
| 230 | struct aa_move attacks[AA_MAX_MOVES], |
| 231 | signed char goal[BOARDMAX]); |
| 232 | static void atari_atari_attack_callback(int anchor, int color, |
| 233 | struct pattern *pattern, |
| 234 | int ll, void *data); |
| 235 | static int atari_atari_find_defense_moves(int targets[AA_MAX_TARGETS_PER_MOVE], |
| 236 | int moves[AA_MAX_MOVES]); |
| 237 | static int get_aa_value(int str); |
| 238 | static int update_aa_goal(signed char goal[BOARDMAX], |
| 239 | signed char new_goal[BOARDMAX], |
| 240 | int apos, int color); |
| 241 | static void aa_init_moves(struct aa_move attacks[AA_MAX_MOVES]); |
| 242 | static void aa_add_move(struct aa_move attacks[AA_MAX_MOVES], |
| 243 | int move, int target); |
| 244 | static int aa_move_known(struct aa_move attacks[AA_MAX_MOVES], |
| 245 | int move, int target); |
| 246 | static void aa_sort_moves(struct aa_move attacks[AA_MAX_MOVES]); |
| 247 | |
| 248 | /* Set to 1 if you want verbose traces from this function. */ |
| 249 | |
| 250 | int |
| 251 | atari_atari(int color, int *attack_move, signed char defense_moves[BOARDMAX], |
| 252 | int save_verbose) |
| 253 | { |
| 254 | int other = OTHER_COLOR(color); |
| 255 | int apos; |
| 256 | int dpos; |
| 257 | int aa_val; |
| 258 | signed char saved_defense_moves[BOARDMAX]; |
| 259 | |
| 260 | /* Collect worm statuses of opponent's worms. We need to |
| 261 | * know this because we only want to report unexpected |
| 262 | * results. For example, we do not want to report success |
| 263 | * if we find we can kill a worm which is already dead. |
| 264 | * The worm status of empty points is set to UNKNOWN to signal |
| 265 | * that stones added along the way need special attention. |
| 266 | */ |
| 267 | if (aa_depth < 2) |
| 268 | return 0; |
| 269 | memset(forbidden, 0, sizeof(forbidden)); |
| 270 | |
| 271 | compute_aa_status(color, NULL); |
| 272 | compute_aa_values(color); |
| 273 | |
| 274 | if (defense_moves) |
| 275 | memset(defense_moves, 0, BOARDMAX); |
| 276 | aa_val = do_atari_atari(color, &apos, &dpos, defense_moves, NO_MOVE, |
| 277 | save_verbose, 0, NULL); |
| 278 | |
| 279 | if (aa_val == 0) |
| 280 | return 0; |
| 281 | |
| 282 | /* We try excluding the first atari found and see if the |
| 283 | * combination still works. Repeat until failure. |
| 284 | */ |
| 285 | while (1) { |
| 286 | int new_aa_val; |
| 287 | |
| 288 | if (attack_move) |
| 289 | *attack_move = apos; |
| 290 | |
| 291 | forbidden[apos] = 1; |
| 292 | if (defense_moves) { |
| 293 | memcpy(saved_defense_moves, defense_moves, BOARDMAX); |
| 294 | memset(defense_moves, 0, BOARDMAX); |
| 295 | } |
| 296 | new_aa_val = do_atari_atari(color, &apos, &dpos, defense_moves, NO_MOVE, |
| 297 | save_verbose, aa_val, NULL); |
| 298 | |
| 299 | /* The last do_atari_atari call fails. When do_atari_atari fails, |
| 300 | * it does not change the value of (apos), so these correspond |
| 301 | * to a move that works and is necessary. |
| 302 | */ |
| 303 | if (new_aa_val == 0) |
| 304 | break; |
| 305 | else |
| 306 | aa_val = new_aa_val; |
| 307 | } |
| 308 | |
| 309 | if (defense_moves) { |
| 310 | int pos; |
| 311 | memcpy(defense_moves, saved_defense_moves, BOARDMAX); |
| 312 | /* defense_moves[] contains potential defense moves. Now we |
| 313 | * examine which of them really work. |
| 314 | */ |
| 315 | forbidden[apos] = 0; |
| 316 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 317 | if (!ON_BOARD(pos) || !defense_moves[pos]) |
| 318 | continue; |
| 319 | |
| 320 | if (!trymove(pos, other, "atari_atari", NO_MOVE)) { |
| 321 | defense_moves[pos] = 0; |
| 322 | if (save_verbose) |
| 323 | gprintf("%1m deleted defense point, illegal\n", pos); |
| 324 | continue; |
| 325 | } |
| 326 | |
| 327 | if (attack(pos, NULL)) { |
| 328 | defense_moves[pos] = 0; |
| 329 | popgo(); |
| 330 | if (save_verbose) |
| 331 | gprintf("%1m deleted defense point, unsafe\n", pos); |
| 332 | continue; |
| 333 | } |
| 334 | |
| 335 | if (do_atari_atari(color, &apos, &dpos, NULL, NO_MOVE, |
| 336 | save_verbose, aa_val, NULL) > 0) { |
| 337 | if (save_verbose) |
| 338 | gprintf("%1m deleted defense point, didn't work\n", pos); |
| 339 | defense_moves[pos] = 0; |
| 340 | } |
| 341 | |
| 342 | popgo(); |
| 343 | } |
| 344 | } |
| 345 | return aa_val; |
| 346 | } |
| 347 | |
| 348 | |
| 349 | /* Wrapper around atari_atari_blunder_size. Check whether a |
| 350 | * combination attack of size at least minsize appears after move |
| 351 | * at (move) has been made. |
| 352 | * The arrays saved_dragons[] and saved_worms[] should be one for |
| 353 | * stones belonging to dragons or worms respectively, which are |
| 354 | * supposedly saved by (move). |
| 355 | * |
| 356 | * FIXME: We probably want to change the calling convention of this |
| 357 | * function to return all defense moves. |
| 358 | */ |
| 359 | int |
| 360 | atari_atari_confirm_safety(int color, int move, int *defense, int minsize, |
| 361 | const signed char saved_dragons[BOARDMAX], |
| 362 | const signed char saved_worms[BOARDMAX]) |
| 363 | { |
| 364 | signed char safe_stones[BOARDMAX]; |
| 365 | signed char defense_moves[BOARDMAX]; |
| 366 | int pos; |
| 367 | int blunder_size; |
| 368 | |
| 369 | mark_safe_stones(color, move, saved_dragons, saved_worms, safe_stones); |
| 370 | blunder_size = atari_atari_blunder_size(color, move, defense_moves, |
| 371 | safe_stones); |
| 372 | |
| 373 | if (defense) { |
| 374 | /* Return one arbitrary defense move. */ |
| 375 | *defense = NO_MOVE; |
| 376 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 377 | if (ON_BOARD(pos) && defense_moves[pos]) { |
| 378 | *defense = pos; |
| 379 | break; |
| 380 | } |
| 381 | } |
| 382 | |
| 383 | return blunder_size >= minsize; |
| 384 | } |
| 385 | |
| 386 | |
| 387 | /* This function checks whether any new combination attack appears after |
| 388 | * move at (move) has been made, and returns its size (in points). |
| 389 | * safe_stones marks which of our stones are supposedly safe after this move. |
| 390 | */ |
| 391 | int |
| 392 | atari_atari_blunder_size(int color, int move, |
| 393 | signed char defense_moves[BOARDMAX], |
| 394 | const signed char safe_stones[BOARDMAX]) |
| 395 | { |
| 396 | int apos; |
| 397 | int defense_point = NO_MOVE; |
| 398 | int aa_val, after_aa_val; |
| 399 | int other = OTHER_COLOR(color); |
| 400 | signed char defense_points[BOARDMAX]; |
| 401 | int last_forbidden = NO_MOVE; |
| 402 | |
| 403 | /* If aa_depth is too small, we can't see any combination attacks, |
| 404 | * so in this respect the move is safe enough. |
| 405 | */ |
| 406 | if (aa_depth < 2) |
| 407 | return 0; |
| 408 | |
| 409 | memset(forbidden, 0, sizeof(forbidden)); |
| 410 | memset(defense_points, 0, sizeof(defense_points)); |
| 411 | |
| 412 | compute_aa_status(other, safe_stones); |
| 413 | compute_aa_values(other); |
| 414 | |
| 415 | /* Accept illegal ko capture here. */ |
| 416 | if (!tryko(move, color, NULL)) |
| 417 | /* Really shouldn't happen. */ |
| 418 | abortgo(__FILE__, __LINE__, "trymove", move); |
| 419 | |
| 420 | increase_depth_values(); |
| 421 | |
| 422 | aa_val = do_atari_atari(other, &apos, &defense_point, defense_points, |
| 423 | NO_MOVE, 0, 0, NULL); |
| 424 | after_aa_val = aa_val; |
| 425 | |
| 426 | if (aa_val == 0 || defense_point == NO_MOVE) { |
| 427 | |
| 428 | /* No sufficiently large combination attack, so the move is safe from |
| 429 | * this danger. |
| 430 | * |
| 431 | * On rare occasions do_atari_atari might find a combination |
| 432 | * but no defense. In this case we assume that the combination |
| 433 | * is illusory. |
| 434 | */ |
| 435 | |
| 436 | popgo(); |
| 437 | decrease_depth_values(); |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | while (aa_val >= after_aa_val && defense_point != NO_MOVE) { |
| 442 | /* Try dropping moves from the combination and see if it still |
| 443 | * works. What we really want is to get the proper defense move |
| 444 | * into (*defense). |
| 445 | */ |
| 446 | forbidden[apos] = 1; |
| 447 | last_forbidden = apos; |
| 448 | aa_val = do_atari_atari(other, &apos, &defense_point, NULL, |
| 449 | NO_MOVE, 0, aa_val, NULL); |
| 450 | } |
| 451 | |
| 452 | popgo(); |
| 453 | decrease_depth_values(); |
| 454 | /* We know that a combination exists, but we don't know if |
| 455 | * the original move at (aa) was really relevant. So we |
| 456 | * try omitting it and see if a combination is still found. |
| 457 | */ |
| 458 | compute_aa_status(other, NULL); |
| 459 | compute_aa_values(other); |
| 460 | forbidden[last_forbidden] = 0; |
| 461 | aa_val = do_atari_atari(other, NULL, NULL, NULL, NO_MOVE, 0, 0, NULL); |
| 462 | if (aa_val >= after_aa_val) |
| 463 | return 0; |
| 464 | |
| 465 | /* Try the potential defense moves to see which are effective. */ |
| 466 | if (defense_moves) { |
| 467 | int pos; |
| 468 | /* defense_points[] contains potential defense moves. Now we |
| 469 | * examine which of them really work. |
| 470 | */ |
| 471 | |
| 472 | /* FIXME: Maybe these should be moved after the tryko() below? */ |
| 473 | compute_aa_status(other, safe_stones); |
| 474 | compute_aa_values(other); |
| 475 | |
| 476 | memcpy(defense_moves, defense_points, sizeof(defense_points)); |
| 477 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 478 | if (!ON_BOARD(pos) || !defense_moves[pos] || pos == move) |
| 479 | continue; |
| 480 | |
| 481 | if (!trymove(pos, color, "atari_atari", NO_MOVE)) { |
| 482 | defense_moves[pos] = 0; |
| 483 | continue; |
| 484 | } |
| 485 | increase_depth_values(); |
| 486 | |
| 487 | if (attack(pos, NULL)) { |
| 488 | defense_moves[pos] = 0; |
| 489 | decrease_depth_values(); |
| 490 | popgo(); |
| 491 | continue; |
| 492 | } |
| 493 | |
| 494 | /* Accept illegal ko capture here. */ |
| 495 | if (!tryko(move, color, NULL)) |
| 496 | /* Really shouldn't happen. */ |
| 497 | abortgo(__FILE__, __LINE__, "trymove", move); |
| 498 | increase_depth_values(); |
| 499 | |
| 500 | if (do_atari_atari(other, &apos, &defense_point, NULL, NO_MOVE, |
| 501 | 0, after_aa_val, NULL) >= after_aa_val) |
| 502 | defense_moves[pos] = 0; |
| 503 | |
| 504 | decrease_depth_values(); |
| 505 | popgo(); |
| 506 | decrease_depth_values(); |
| 507 | popgo(); |
| 508 | } |
| 509 | } |
| 510 | |
| 511 | return after_aa_val - aa_val; |
| 512 | } |
| 513 | |
| 514 | |
| 515 | /* ---------------------------------------------------------------- */ |
| 516 | /* Helper functions for atari_atari. */ |
| 517 | /* ---------------------------------------------------------------- */ |
| 518 | |
| 519 | |
| 520 | /* Helper function for computing the aa_status for all opponent's strings. |
| 521 | * If safe_stones is given, we just copy the information from there. |
| 522 | * If called at stackp > 0, safe_stones must be provided since the |
| 523 | * dragon_data is not valid then. |
| 524 | */ |
| 525 | |
| 526 | static void |
| 527 | compute_aa_status(int color, const signed char safe_stones[BOARDMAX]) |
| 528 | { |
| 529 | int other = OTHER_COLOR(color); |
| 530 | int pos; |
| 531 | SGFTree *save_sgf_dumptree = sgf_dumptree; |
| 532 | int save_count_variations = count_variations; |
| 533 | int save_verbose = verbose; |
| 534 | |
| 535 | gg_assert(safe_stones || stackp == 0); |
| 536 | |
| 537 | sgf_dumptree = NULL; |
| 538 | count_variations = 0; |
| 539 | if (verbose) |
| 540 | verbose--; |
| 541 | |
| 542 | /* Collect worm statuses of opponent's worms. We need to |
| 543 | * know this because we only want to report unexpected |
| 544 | * results. For example, we do not want to report success |
| 545 | * if we find we can kill a worm which is already dead. |
| 546 | * The worm status of empty points is set to UNKNOWN to signal |
| 547 | * that stones added along the way need special attention. |
| 548 | */ |
| 549 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 550 | if (board[pos] == other) { |
| 551 | if (safe_stones) { |
| 552 | if (safe_stones[pos]) |
| 553 | aa_status[pos] = ALIVE; |
| 554 | else |
| 555 | aa_status[pos] = DEAD; |
| 556 | } |
| 557 | else { |
| 558 | if (dragon[pos].status == DEAD) |
| 559 | aa_status[pos] = DEAD; |
| 560 | else if (dragon[pos].status == CRITICAL) |
| 561 | aa_status[pos] = CRITICAL; |
| 562 | else if (worm[pos].attack_codes[0] != 0) { |
| 563 | if (worm[pos].defense_codes[0] != 0) |
| 564 | aa_status[pos] = CRITICAL; |
| 565 | else |
| 566 | aa_status[pos] = DEAD; |
| 567 | } |
| 568 | else |
| 569 | aa_status[pos] = ALIVE; |
| 570 | } |
| 571 | } |
| 572 | else if (ON_BOARD(pos)) |
| 573 | aa_status[pos] = UNKNOWN; |
| 574 | } |
| 575 | |
| 576 | /* reclassify a worm with 2 liberties as INSUBSTANTIAL if capturing |
| 577 | * it does not result in a live group. |
| 578 | */ |
| 579 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 580 | if (board[pos] == other |
| 581 | && find_origin(pos) == pos |
| 582 | && countlib(pos) == 2 |
| 583 | && aa_status[pos] == ALIVE) { |
| 584 | int libs[2]; |
| 585 | findlib(pos, 2, libs); |
| 586 | /* Don't waste time running owl_substantial() if we can't safely |
| 587 | * atari anyway. |
| 588 | */ |
| 589 | if (is_self_atari(libs[0], color) |
| 590 | && is_self_atari(libs[1], color)) |
| 591 | continue; |
| 592 | |
| 593 | if (!owl_substantial(pos)) { |
| 594 | int pos2; |
| 595 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) |
| 596 | if (board[pos2] == other && find_origin(pos2) == pos) |
| 597 | aa_status[pos2] = INSUBSTANTIAL; |
| 598 | } |
| 599 | } |
| 600 | } |
| 601 | |
| 602 | if (debug & DEBUG_ATARI_ATARI) { |
| 603 | gprintf("compute_aa_status() for %C\n", color); |
| 604 | gprintf("aa_status: (ALIVE worms not listed)\n"); |
| 605 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 606 | if (board[pos] == other && is_worm_origin(pos, pos)) { |
| 607 | const char *status = "UNKNOWN (shouldn't happen)"; |
| 608 | if (aa_status[pos] == DEAD) |
| 609 | status = "DEAD"; |
| 610 | else if (aa_status[pos] == CRITICAL) |
| 611 | status = "CRITICAL"; |
| 612 | else if (aa_status[pos] == INSUBSTANTIAL) |
| 613 | status = "INSUBSTANTIAL"; |
| 614 | |
| 615 | if (aa_status[pos] != ALIVE) |
| 616 | gprintf("%1M: %s\n", pos, status); |
| 617 | } |
| 618 | } |
| 619 | } |
| 620 | |
| 621 | sgf_dumptree = save_sgf_dumptree; |
| 622 | count_variations = save_count_variations; |
| 623 | verbose = save_verbose; |
| 624 | } |
| 625 | |
| 626 | |
| 627 | /* Helper function for retrieving the aa_status for a string. We can't |
| 628 | * reliably do this simply by looking up aa_status[pos] since this is |
| 629 | * only valid at vertices which were non-empty at the start of the |
| 630 | * reading. For later added stones, we need to find their aa_status by |
| 631 | * locating a part of the string which was a worm at the beginning of |
| 632 | * the reading. |
| 633 | */ |
| 634 | |
| 635 | static int |
| 636 | get_aa_status(int pos) |
| 637 | { |
| 638 | int stones[MAX_BOARD * MAX_BOARD]; |
| 639 | int num_stones; |
| 640 | int k; |
| 641 | |
| 642 | if (aa_status[pos] != UNKNOWN) |
| 643 | return aa_status[pos]; |
| 644 | |
| 645 | num_stones = findstones(pos, MAX_BOARD * MAX_BOARD, stones); |
| 646 | for (k = 0; k < num_stones; k++) |
| 647 | if (aa_status[stones[k]] != UNKNOWN) |
| 648 | return aa_status[stones[k]]; |
| 649 | |
| 650 | return UNKNOWN; |
| 651 | } |
| 652 | |
| 653 | |
| 654 | |
| 655 | /* Helper function for atari_atari. Here worms is the number of |
| 656 | * opponent worms involved in the combination, and (last_friendly) is |
| 657 | * the location of the last friendly move played. Moves marked |
| 658 | * with the forbidden array are not tried. If no move is found, |
| 659 | * the values of *attack_point and *defense_point are not changed. |
| 660 | * |
| 661 | * If not NULL, *attack_point is left pointing to the location of the |
| 662 | * attacking move, and *defense_point points to a move defending the |
| 663 | * combination. In rare cases a defensive move might not be found. If |
| 664 | * a non-static function calling do_atari_atari gets a return value of |
| 665 | * 1 but NO_MOVE as the defense point, this should be treated as |
| 666 | * equivalent to a return value of 0. |
| 667 | * |
| 668 | * The goal array limits where we are allowed to consider threats. |
| 669 | * Only strings for which goal is set to 1 may be threatened. If goal |
| 670 | * is NULL, anything may be attacked. Thus goal is typically NULL when |
| 671 | * do_atari_atari() is called from an external function. After the |
| 672 | * first threat has been made, the goal array is set to one in a |
| 673 | * neighborhood of the move and after subsequent threats it is |
| 674 | * expanded with neighborhoods of those moves. The details of this can |
| 675 | * be found in the function update_aa_goal(). |
| 676 | */ |
| 677 | |
| 678 | static int |
| 679 | do_atari_atari(int color, int *attack_point, int *defense_point, |
| 680 | signed char all_potential_defenses[BOARDMAX], int last_friendly, |
| 681 | int save_verbose, int minsize, signed char goal[BOARDMAX]) |
| 682 | { |
| 683 | int other = OTHER_COLOR(color); |
| 684 | int k; |
| 685 | struct aa_move attacks[AA_MAX_MOVES]; |
| 686 | int num_defense_moves; |
| 687 | int defense_moves[AA_MAX_MOVES]; |
| 688 | int pos; |
| 689 | SGFTree *save_sgf_dumptree; |
| 690 | int save_count_variations; |
| 691 | |
| 692 | if (debug & DEBUG_ATARI_ATARI) { |
| 693 | gprintf("%odo_atari_atari: "); |
| 694 | dump_stack(); |
| 695 | gprintf("%oforbidden moves: "); |
| 696 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 697 | if (ON_BOARD(pos) && forbidden[pos]) |
| 698 | gprintf("%o%1m ", pos); |
| 699 | gprintf("\n"); |
| 700 | gprintf("%ogoal: "); |
| 701 | if (!goal) |
| 702 | gprintf("none"); |
| 703 | else { |
| 704 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 705 | if (ON_BOARD(pos) && goal[pos]) |
| 706 | gprintf("%o%1m ", pos); |
| 707 | } |
| 708 | gprintf("\n"); |
| 709 | } |
| 710 | |
| 711 | /* First look for strings adjacent to the last friendly move played |
| 712 | * (or to another stone in the same string) which can be |
| 713 | * unexpectedly attacked. If so, the combination attack |
| 714 | * has succeeded. |
| 715 | */ |
| 716 | if (last_friendly != NO_MOVE) { |
| 717 | int retval; |
| 718 | save_sgf_dumptree = sgf_dumptree; |
| 719 | save_count_variations = count_variations; |
| 720 | sgf_dumptree = NULL; |
| 721 | count_variations = 0; |
| 722 | retval = atari_atari_succeeded(color, attack_point, defense_point, |
| 723 | last_friendly, save_verbose, minsize); |
| 724 | sgf_dumptree = save_sgf_dumptree; |
| 725 | count_variations = save_count_variations; |
| 726 | if (retval != 0) { |
| 727 | if (sgf_dumptree) |
| 728 | /* FIXME: Better message. */ |
| 729 | sgftreeAddComment(sgf_dumptree, "attack found"); |
| 730 | return retval; |
| 731 | } |
| 732 | } |
| 733 | |
| 734 | if (stackp > aa_depth) |
| 735 | return 0; |
| 736 | |
| 737 | /* Find attack moves. These are typically ataris but may also be |
| 738 | * more general. |
| 739 | */ |
| 740 | save_sgf_dumptree = sgf_dumptree; |
| 741 | save_count_variations = count_variations; |
| 742 | sgf_dumptree = NULL; |
| 743 | count_variations = 0; |
| 744 | atari_atari_find_attack_moves(color, minsize, attacks, goal); |
| 745 | sgf_dumptree = save_sgf_dumptree; |
| 746 | count_variations = save_count_variations; |
| 747 | |
| 748 | /* Try the attacking moves and let the opponent defend. Then call |
| 749 | * ourselves recursively. |
| 750 | */ |
| 751 | for (k = 0; attacks[k].move != NO_MOVE; k++) { |
| 752 | int aa_val; |
| 753 | int str = attacks[k].target[0]; |
| 754 | int apos = attacks[k].move; |
| 755 | int bpos; |
| 756 | int r; |
| 757 | |
| 758 | if (!trymove(apos, color, "do_atari_atari-A", str)) |
| 759 | continue; |
| 760 | |
| 761 | if (all_potential_defenses) { |
| 762 | all_potential_defenses[apos] = 1; |
| 763 | if (countlib(apos) <= 2) { |
| 764 | int libs[2]; |
| 765 | int num_libs = findlib(apos, 2, libs); |
| 766 | all_potential_defenses[libs[0]] = 1; |
| 767 | if (num_libs == 2) |
| 768 | all_potential_defenses[libs[1]] = 1; |
| 769 | } |
| 770 | } |
| 771 | |
| 772 | if (!IS_STONE(board[str])) { |
| 773 | /* Error situation. This could be caused by a wrong matcher status. */ |
| 774 | if (save_verbose || (debug & DEBUG_ATARI_ATARI)) |
| 775 | gprintf("%oError condition found by atari_atari\n"); |
| 776 | popgo(); |
| 777 | return 0; |
| 778 | } |
| 779 | |
| 780 | /* Try to defend the stone (str) which is threatened. */ |
| 781 | aa_val = get_aa_value(str); |
| 782 | |
| 783 | /* Pick up defense moves. */ |
| 784 | save_sgf_dumptree = sgf_dumptree; |
| 785 | save_count_variations = count_variations; |
| 786 | sgf_dumptree = NULL; |
| 787 | count_variations = 0; |
| 788 | num_defense_moves = atari_atari_find_defense_moves(attacks[k].target, |
| 789 | defense_moves); |
| 790 | sgf_dumptree = save_sgf_dumptree; |
| 791 | count_variations = save_count_variations; |
| 792 | |
| 793 | for (r = 0; r < num_defense_moves; r++) { |
| 794 | bpos = defense_moves[r]; |
| 795 | |
| 796 | if (all_potential_defenses) |
| 797 | all_potential_defenses[bpos] = 1; |
| 798 | |
| 799 | if (trymove(bpos, other, "do_atari_atari-B", str)) { |
| 800 | int new_aa_val; |
| 801 | signed char new_goal[BOARDMAX]; |
| 802 | /* These moves may have been irrelevant for later |
| 803 | * reading, so in order to avoid horizon problems, we |
| 804 | * need to temporarily increase the depth values. |
| 805 | */ |
| 806 | modify_depth_values(2); |
| 807 | update_aa_goal(goal, new_goal, apos, color); |
| 808 | new_aa_val = do_atari_atari(color, NULL, defense_point, |
| 809 | all_potential_defenses, |
| 810 | apos, save_verbose, minsize, new_goal); |
| 811 | modify_depth_values(-2); |
| 812 | if (new_aa_val < aa_val) |
| 813 | aa_val = new_aa_val; |
| 814 | popgo(); |
| 815 | } |
| 816 | |
| 817 | /* Defense successful, no need to try any further. */ |
| 818 | if (aa_val == 0) |
| 819 | break; |
| 820 | } |
| 821 | |
| 822 | /* Undo the attacking move. */ |
| 823 | popgo(); |
| 824 | |
| 825 | if (aa_val == 0) |
| 826 | continue; |
| 827 | |
| 828 | /* atari_atari successful */ |
| 829 | if (num_defense_moves == 0) { |
| 830 | if (save_verbose || (debug & DEBUG_ATARI_ATARI)) { |
| 831 | gprintf("%oThe worm %1m can be attacked at %1m after ", str, apos); |
| 832 | dump_stack(); |
| 833 | } |
| 834 | if (sgf_dumptree) |
| 835 | /* FIXME: Better message. */ |
| 836 | sgftreeAddComment(sgf_dumptree, "attack found"); |
| 837 | } |
| 838 | |
| 839 | if (attack_point) |
| 840 | *attack_point = apos; |
| 841 | |
| 842 | if (defense_point) { |
| 843 | save_sgf_dumptree = sgf_dumptree; |
| 844 | save_count_variations = count_variations; |
| 845 | sgf_dumptree = NULL; |
| 846 | count_variations = 0; |
| 847 | |
| 848 | if (!find_defense(str, defense_point)) |
| 849 | *defense_point = NO_MOVE; |
| 850 | |
| 851 | /* If no defense point is known and (apos) is a safe |
| 852 | * move for other, it probably defends the combination. |
| 853 | */ |
| 854 | if ((*defense_point == NO_MOVE || !safe_move(*defense_point, other)) |
| 855 | && safe_move(apos, other)) |
| 856 | *defense_point = apos; |
| 857 | |
| 858 | sgf_dumptree = save_sgf_dumptree; |
| 859 | count_variations = save_count_variations; |
| 860 | } |
| 861 | |
| 862 | DEBUG(DEBUG_ATARI_ATARI, "%oreturn value:%d (%1m)\n", aa_val, str); |
| 863 | return aa_val; |
| 864 | } |
| 865 | |
| 866 | /* No atari_atari attack. */ |
| 867 | return 0; |
| 868 | } |
| 869 | |
| 870 | |
| 871 | static int |
| 872 | atari_atari_succeeded(int color, int *attack_point, int *defense_point, |
| 873 | int last_friendly, int save_verbose, int minsize) |
| 874 | { |
| 875 | int pos; |
| 876 | int apos; |
| 877 | int other = OTHER_COLOR(color); |
| 878 | |
| 879 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 880 | if (board[pos] != other) |
| 881 | continue; |
| 882 | |
| 883 | if (pos != find_origin(pos)) |
| 884 | continue; |
| 885 | |
| 886 | if (minsize > 0 |
| 887 | && get_aa_value(pos) < minsize) |
| 888 | continue; |
| 889 | |
| 890 | if (get_aa_status(pos) != ALIVE) |
| 891 | continue; |
| 892 | |
| 893 | if (board[last_friendly] != EMPTY |
| 894 | && !adjacent_strings(last_friendly, pos)) |
| 895 | continue; |
| 896 | |
| 897 | if (board[last_friendly] == EMPTY |
| 898 | && !liberty_of_string(last_friendly, pos)) |
| 899 | continue; |
| 900 | |
| 901 | if (debug & DEBUG_ATARI_ATARI) |
| 902 | gprintf("Considering attack of %1m. depth = %d.\n", pos, depth); |
| 903 | |
| 904 | if (attack(pos, &apos) && !forbidden[apos]) { |
| 905 | if (save_verbose || (debug & DEBUG_ATARI_ATARI)) { |
| 906 | gprintf("%oThe worm %1m can be attacked at %1m after ", pos, apos); |
| 907 | dump_stack(); |
| 908 | } |
| 909 | if (attack_point) |
| 910 | *attack_point = apos; |
| 911 | |
| 912 | /* We look for a move defending the combination. |
| 913 | * Normally this is found by find_defense but failing |
| 914 | * that, if the attacking move is a safe move for color, |
| 915 | * it probably defends. |
| 916 | */ |
| 917 | if (defense_point) { |
| 918 | if (!find_defense(pos, defense_point)) { |
| 919 | if (safe_move(apos, other)) |
| 920 | *defense_point = apos; |
| 921 | else |
| 922 | *defense_point = NO_MOVE; |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | DEBUG(DEBUG_ATARI_ATARI, "%oreturn value:%d (%1m)\n", |
| 927 | get_aa_value(pos), pos); |
| 928 | return get_aa_value(pos); |
| 929 | } |
| 930 | } |
| 931 | |
| 932 | return 0; |
| 933 | } |
| 934 | |
| 935 | #define MAX_THREAT_MOVES MAX_TACTICAL_POINTS |
| 936 | |
| 937 | static void |
| 938 | atari_atari_find_attack_moves(int color, int minsize, |
| 939 | struct aa_move attacks[AA_MAX_MOVES], |
| 940 | signed char goal[BOARDMAX]) |
| 941 | { |
| 942 | int k; |
| 943 | int r; |
| 944 | |
| 945 | aa_init_moves(attacks); |
| 946 | |
| 947 | atari_atari_attack_patterns(color, minsize, attacks, goal); |
| 948 | |
| 949 | /* Sort the attack moves. */ |
| 950 | aa_sort_moves(attacks); |
| 951 | |
| 952 | if (debug & DEBUG_ATARI_ATARI) { |
| 953 | gprintf("Attack moves:"); |
| 954 | for (k = 0; k < AA_MAX_MOVES && attacks[k].move != NO_MOVE; k++) { |
| 955 | gprintf("%o %1m(", attacks[k].move); |
| 956 | for (r = 0; r < AA_MAX_TARGETS_PER_MOVE; r++) { |
| 957 | if (attacks[k].target[r] == NO_MOVE) |
| 958 | break; |
| 959 | gprintf("%o%s%1m", r == 0 ? "" : ",", attacks[k].target[r]); |
| 960 | } |
| 961 | gprintf("%o)"); |
| 962 | } |
| 963 | gprintf("%o\n"); |
| 964 | } |
| 965 | } |
| 966 | |
| 967 | /* FIXME: Move these to a struct and pass to callback through the |
| 968 | * *data parameter. |
| 969 | */ |
| 970 | static int current_minsize; |
| 971 | static struct aa_move *current_attacks; |
| 972 | static int conditional_attack_point[BOARDMAX]; |
| 973 | |
| 974 | static void |
| 975 | atari_atari_attack_patterns(int color, int minsize, |
| 976 | struct aa_move attacks[AA_MAX_MOVES], |
| 977 | signed char goal[BOARDMAX]) |
| 978 | { |
| 979 | signed char revised_goal[BOARDMAX]; |
| 980 | current_minsize = minsize; |
| 981 | current_attacks = attacks; |
| 982 | memset(conditional_attack_point, 0, sizeof(conditional_attack_point)); |
| 983 | |
| 984 | /* If goal is NULL and there are forbidden moves we need to compute |
| 985 | * a new goal around the forbidden moves. |
| 986 | */ |
| 987 | if (goal == NULL && update_aa_goal(goal, revised_goal, NO_MOVE, color)) |
| 988 | goal = revised_goal; |
| 989 | |
| 990 | #if 0 |
| 991 | if (goal != NULL) { |
| 992 | int pos; |
| 993 | gprintf("goal:"); |
| 994 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 995 | if (ON_BOARD(pos) && goal[pos]) |
| 996 | gprintf("%o %1m", pos); |
| 997 | gprintf("%o\n"); |
| 998 | } |
| 999 | #endif |
| 1000 | |
| 1001 | matchpat(atari_atari_attack_callback, color, &aa_attackpat_db, NULL, goal); |
| 1002 | } |
| 1003 | |
| 1004 | /* Try to attack every X string in the pattern, whether there is an attack |
| 1005 | * before or not. Only exclude already known attacking moves. |
| 1006 | */ |
| 1007 | static void |
| 1008 | atari_atari_attack_callback(int anchor, int color, |
| 1009 | struct pattern *pattern, int ll, void *data) |
| 1010 | { |
| 1011 | int move; |
| 1012 | int k; |
| 1013 | UNUSED(data); |
| 1014 | |
| 1015 | move = AFFINE_TRANSFORM(pattern->move_offset, ll, anchor); |
| 1016 | |
| 1017 | if (forbidden[move]) |
| 1018 | return; |
| 1019 | |
| 1020 | /* If the pattern has a constraint, call the autohelper to see |
| 1021 | * if the pattern must be rejected. |
| 1022 | */ |
| 1023 | if (pattern->autohelper_flag & HAVE_CONSTRAINT) |
| 1024 | if (!pattern->autohelper(ll, move, color, 0)) |
| 1025 | return; |
| 1026 | |
| 1027 | /* If the pattern has a helper, call it to see if the pattern must |
| 1028 | * be rejected. |
| 1029 | */ |
| 1030 | if (pattern->helper) |
| 1031 | if (!pattern->helper(pattern, ll, move, color)) |
| 1032 | return; |
| 1033 | |
| 1034 | /* Loop through pattern elements in search of X strings to |
| 1035 | * threaten to attack. |
| 1036 | */ |
| 1037 | for (k = 0; k < pattern->patlen; ++k) { /* match each point */ |
| 1038 | if (pattern->patn[k].att == ATT_X) { |
| 1039 | /* transform pattern real coordinate */ |
| 1040 | int str = find_origin(AFFINE_TRANSFORM(pattern->patn[k].offset, |
| 1041 | ll, anchor)); |
| 1042 | |
| 1043 | if (current_minsize > 0 |
| 1044 | && get_aa_value(str) < current_minsize) |
| 1045 | continue; |
| 1046 | |
| 1047 | if (aa_move_known(current_attacks, move, str)) |
| 1048 | continue; |
| 1049 | |
| 1050 | if (get_aa_status(str) != ALIVE) |
| 1051 | continue; |
| 1052 | |
| 1053 | /* Usually we don't want to play self atari. However, if we |
| 1054 | * capture in snapback it's okay. For s class patterns we don't |
| 1055 | * have this requirement. |
| 1056 | */ |
| 1057 | if (!(pattern->class & CLASS_s) && is_self_atari(move, color)) { |
| 1058 | if (countlib(str) > 2) |
| 1059 | continue; |
| 1060 | |
| 1061 | if (!safe_move(move, color)) |
| 1062 | continue; |
| 1063 | } |
| 1064 | |
| 1065 | /* |
| 1066 | * Play (move) and see if there is an attack. |
| 1067 | */ |
| 1068 | if (trymove(move, color, "attack_callback", str)) { |
| 1069 | int acode; |
| 1070 | int attack_point = NO_MOVE; |
| 1071 | |
| 1072 | if (!board[str]) |
| 1073 | acode = WIN; |
| 1074 | else |
| 1075 | acode = attack(str, &attack_point); |
| 1076 | |
| 1077 | popgo(); |
| 1078 | |
| 1079 | if (acode != 0) { |
| 1080 | if ((pattern->class & CLASS_c) |
| 1081 | && !aa_move_known(current_attacks, move, NO_MOVE)) { |
| 1082 | /* Conditional pattern. */ |
| 1083 | DEBUG(DEBUG_ATARI_ATARI, |
| 1084 | "aa_attack pattern %s+%d (conditional) found threat on %1m at %1m with code %d\n", |
| 1085 | pattern->name, ll, str, move, acode); |
| 1086 | if (conditional_attack_point[move] == NO_MOVE) |
| 1087 | conditional_attack_point[move] = str; |
| 1088 | else if (conditional_attack_point[move] != str) { |
| 1089 | aa_add_move(current_attacks, move, |
| 1090 | conditional_attack_point[move]); |
| 1091 | aa_add_move(current_attacks, move, str); |
| 1092 | } |
| 1093 | } |
| 1094 | else { |
| 1095 | aa_add_move(current_attacks, move, str); |
| 1096 | DEBUG(DEBUG_ATARI_ATARI, |
| 1097 | "aa_attack pattern %s+%d found threat on %1m at %1m with code %d\n", |
| 1098 | pattern->name, ll, str, move, acode); |
| 1099 | } |
| 1100 | } |
| 1101 | } |
| 1102 | } |
| 1103 | } |
| 1104 | } |
| 1105 | |
| 1106 | |
| 1107 | static int |
| 1108 | atari_atari_find_defense_moves(int targets[AA_MAX_TARGETS_PER_MOVE], |
| 1109 | int moves[AA_MAX_MOVES]) |
| 1110 | { |
| 1111 | int num_moves = 0; |
| 1112 | int move; |
| 1113 | int k; |
| 1114 | int liberties; |
| 1115 | int libs[4]; |
| 1116 | int neighbors; |
| 1117 | int adjs[MAXCHAIN]; |
| 1118 | int mx[BOARDMAX]; |
| 1119 | int r, s; |
| 1120 | |
| 1121 | memset(mx, 0, sizeof(mx)); |
| 1122 | |
| 1123 | for (r = 0; r < AA_MAX_TARGETS_PER_MOVE && targets[r] != NO_MOVE; r++) { |
| 1124 | int str = targets[r]; |
| 1125 | |
| 1126 | /* If the attack move happened to remove (str), there's no defense. */ |
| 1127 | if (board[str] == EMPTY) |
| 1128 | continue; |
| 1129 | |
| 1130 | /* Because we know (str) is threatened there is an |
| 1131 | * attack and we can be sure find_defense() will give a |
| 1132 | * useful defense point if it returns non-zero. Usually we |
| 1133 | * would need to call attack_and_defend() to be certain of |
| 1134 | * this. |
| 1135 | */ |
| 1136 | if (!find_defense(str, &move)) |
| 1137 | continue; |
| 1138 | moves[num_moves++] = move; |
| 1139 | if (num_moves == AA_MAX_MOVES) |
| 1140 | return num_moves; |
| 1141 | mx[move] = 1; |
| 1142 | |
| 1143 | /* Consider all moves to attack a neighbor or to play on a liberty. */ |
| 1144 | liberties = findlib(str, 4, libs); |
| 1145 | for (k = 0; k < liberties; k++) { |
| 1146 | if (!mx[libs[k]] |
| 1147 | && trymove(libs[k], board[str], "aa_defend-A", str)) { |
| 1148 | if (attack(str, NULL) == 0) { |
| 1149 | moves[num_moves++] = libs[k]; |
| 1150 | mx[libs[k]] = 1; |
| 1151 | } |
| 1152 | popgo(); |
| 1153 | if (num_moves == AA_MAX_MOVES) |
| 1154 | return num_moves; |
| 1155 | } |
| 1156 | } |
| 1157 | |
| 1158 | neighbors = chainlinks(str, adjs); |
| 1159 | for (k = 0; k < neighbors; k++) { |
| 1160 | int attack_point; |
| 1161 | if (attack(adjs[k], &attack_point) == WIN |
| 1162 | && !mx[attack_point]) { |
| 1163 | moves[num_moves++] = attack_point; |
| 1164 | if (num_moves == AA_MAX_MOVES) |
| 1165 | return num_moves; |
| 1166 | mx[attack_point] = 1; |
| 1167 | } |
| 1168 | |
| 1169 | /* If the neighbor has at most three liberties, try all of them |
| 1170 | * for defense, except self-ataris. |
| 1171 | */ |
| 1172 | liberties = findlib(adjs[k], 3, libs); |
| 1173 | if (liberties <= 3) { |
| 1174 | for (s = 0; s < liberties; s++) { |
| 1175 | if (!mx[libs[s]] |
| 1176 | && !is_self_atari(libs[s], board[str]) |
| 1177 | && trymove(libs[s], board[str], "aa_defend-B", str)) { |
| 1178 | if (attack(str, NULL) == 0) { |
| 1179 | moves[num_moves++] = libs[s]; |
| 1180 | mx[libs[s]] = 1; |
| 1181 | } |
| 1182 | popgo(); |
| 1183 | if (num_moves == AA_MAX_MOVES) |
| 1184 | return num_moves; |
| 1185 | } |
| 1186 | } |
| 1187 | } |
| 1188 | } |
| 1189 | |
| 1190 | if (debug & DEBUG_ATARI_ATARI) { |
| 1191 | gprintf("Defense moves for %1m:", str); |
| 1192 | for (k = 0; k < num_moves; k++) |
| 1193 | gprintf("%o %1m", moves[k]); |
| 1194 | gprintf("%o\n"); |
| 1195 | } |
| 1196 | } |
| 1197 | |
| 1198 | return num_moves; |
| 1199 | } |
| 1200 | |
| 1201 | |
| 1202 | /* Try to guess the value of the strings. We do this by adding twice |
| 1203 | * the number of stones to the number of liberties and second order |
| 1204 | * liberties within the moyo around the string. This is of course |
| 1205 | * quite crude since it doesn't take into account any strategic |
| 1206 | * effects, e.g. a string being cutting stones. |
| 1207 | */ |
| 1208 | static void |
| 1209 | compute_aa_values(int color) |
| 1210 | { |
| 1211 | int other = OTHER_COLOR(color); |
| 1212 | int pos; |
| 1213 | int value; |
| 1214 | int liberties; |
| 1215 | int libs[MAXLIBS]; |
| 1216 | int mx[BOARDMAX]; |
| 1217 | int r, k; |
| 1218 | |
| 1219 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 1220 | if (board[pos] != other |
| 1221 | || pos != find_origin(pos) |
| 1222 | || aa_status[pos] != ALIVE) { |
| 1223 | aa_values[pos] = 0; |
| 1224 | continue; |
| 1225 | } |
| 1226 | |
| 1227 | memset(mx, 0, sizeof(mx)); |
| 1228 | liberties = findlib(pos, MAXLIBS, libs); |
| 1229 | value = 2 * countstones(pos); |
| 1230 | |
| 1231 | for (r = 0; r < liberties; r++) { |
| 1232 | if (!mx[libs[r]] |
| 1233 | && (whose_moyo(&initial_black_influence, libs[r]) == other |
| 1234 | || whose_moyo(&initial_white_influence, libs[r]) == other)) { |
| 1235 | mx[libs[r]] = 1; |
| 1236 | value++; |
| 1237 | } |
| 1238 | for (k = 0; k < 4; k++) { |
| 1239 | int librd = libs[r] + delta[k]; |
| 1240 | if (!ON_BOARD1(librd) || mx[librd]) |
| 1241 | continue; |
| 1242 | mx[librd] = 1; |
| 1243 | if (board[librd] == EMPTY |
| 1244 | && (whose_moyo(&initial_black_influence, librd) == other |
| 1245 | || (whose_moyo(&initial_white_influence, librd) == other))) |
| 1246 | value++; |
| 1247 | } |
| 1248 | } |
| 1249 | |
| 1250 | aa_values[pos] = value; |
| 1251 | if (1) |
| 1252 | DEBUG(DEBUG_ATARI_ATARI, "aa_value for %1m = %d\n", pos, value); |
| 1253 | } |
| 1254 | } |
| 1255 | |
| 1256 | /* The aa_value for a string is the sum of the aa_values for all |
| 1257 | * included strings in the original position. This will systematically |
| 1258 | * overvalue strings which consist of multiple original strings, but |
| 1259 | * this is okay since the defender very rarely should defend a string |
| 1260 | * first and then sacrifice it later. |
| 1261 | */ |
| 1262 | static int |
| 1263 | get_aa_value(int str) |
| 1264 | { |
| 1265 | int stones[MAX_BOARD * MAX_BOARD]; |
| 1266 | int k; |
| 1267 | int num_stones = findstones(str, MAX_BOARD * MAX_BOARD, stones); |
| 1268 | int value = 0; |
| 1269 | |
| 1270 | for (k = 0; k < num_stones; k++) |
| 1271 | value += aa_values[stones[k]]; |
| 1272 | |
| 1273 | return value; |
| 1274 | } |
| 1275 | |
| 1276 | |
| 1277 | /* update_aa_goal(goal, new_goal, apos, color) extends the goal array |
| 1278 | * with vertices in a neighborhood of apos. The algorithm is that |
| 1279 | * starting at apos, a distance measure is computed to nearby |
| 1280 | * vertices. The distance increases with one for each step through |
| 1281 | * empty vertices and by a liberty depending number when passing |
| 1282 | * through strings of the attacked color. Strings with 3 or fewer |
| 1283 | * liberties are free to pass through while strings with more |
| 1284 | * liberties cost (libs - 3) to pass through. Stones with a distance |
| 1285 | * of 5 or less are included in the goal. |
| 1286 | * |
| 1287 | * Additionally neighborhoods of the moves in the forbidden array are |
| 1288 | * included in the goal, to make it possible to limit the goal to a |
| 1289 | * specific area from the beginning. This is needed when trying to |
| 1290 | * decide which moves are relevant to the combination. |
| 1291 | */ |
| 1292 | |
| 1293 | #define ENQUEUE(pos, dist) \ |
| 1294 | do { \ |
| 1295 | if ((dist) <= MAX_AA_DIST) { \ |
| 1296 | if (dists[pos] == 0) { \ |
| 1297 | queue[queue_end++] = (pos); \ |
| 1298 | dists[pos] = (dist); \ |
| 1299 | } \ |
| 1300 | else if (dists[pos] < (dist)) \ |
| 1301 | dists[pos] = (dist); \ |
| 1302 | } \ |
| 1303 | } while (0); |
| 1304 | |
| 1305 | static int |
| 1306 | update_aa_goal(signed char goal[BOARDMAX], signed char new_goal[BOARDMAX], |
| 1307 | int apos, int color) |
| 1308 | { |
| 1309 | int other = OTHER_COLOR(color); |
| 1310 | int dists[BOARDMAX]; |
| 1311 | int queue[MAX_BOARD * MAX_BOARD]; |
| 1312 | int queue_end = 0; |
| 1313 | int k, r, s; |
| 1314 | int pos; |
| 1315 | |
| 1316 | if (goal == NULL) |
| 1317 | memset(new_goal, 0, BOARDMAX); |
| 1318 | else |
| 1319 | memcpy(new_goal, goal, BOARDMAX); |
| 1320 | |
| 1321 | memset(dists, 0, sizeof(dists)); |
| 1322 | |
| 1323 | if (apos != NO_MOVE) { |
| 1324 | dists[apos] = 1; |
| 1325 | queue[queue_end++] = apos; |
| 1326 | } |
| 1327 | |
| 1328 | #if 0 |
| 1329 | /* Disabled for now, since it does nothing but break atari_atari:16 |
| 1330 | * and trevorc:1540. It could be reactivated when the rest of the |
| 1331 | * function would be modified in order to garanty that a forbidden |
| 1332 | * move is strictly equivalent to a played move in terms of goal |
| 1333 | * mapping. I doubt it would be anything worth though... |
| 1334 | */ |
| 1335 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 1336 | if (ON_BOARD(pos) && forbidden[pos]) { |
| 1337 | dists[pos] = 1; |
| 1338 | queue[queue_end++] = pos; |
| 1339 | } |
| 1340 | } |
| 1341 | #endif |
| 1342 | |
| 1343 | if (queue_end == 0) |
| 1344 | return 0; |
| 1345 | |
| 1346 | for (r = 0; r < queue_end; r++) { |
| 1347 | int smallest_dist = MAX_BOARD * MAX_BOARD; |
| 1348 | int best_index = -1; |
| 1349 | |
| 1350 | gg_assert(queue_end < MAX_BOARD * MAX_BOARD); |
| 1351 | |
| 1352 | for (k = r; k < queue_end; k++) { |
| 1353 | if (dists[queue[k]] < smallest_dist) { |
| 1354 | smallest_dist = dists[queue[k]]; |
| 1355 | best_index = k; |
| 1356 | } |
| 1357 | } |
| 1358 | |
| 1359 | if (best_index != r) { |
| 1360 | int tmp = queue[r]; |
| 1361 | queue[r] = queue[best_index]; |
| 1362 | queue[best_index] = tmp; |
| 1363 | } |
| 1364 | |
| 1365 | pos = queue[r]; |
| 1366 | if (board[pos] == other) |
| 1367 | new_goal[pos] = 1; |
| 1368 | |
| 1369 | /* FIXME: We shouldn't let dead opponent stones stop the |
| 1370 | * propagation of distance. |
| 1371 | * |
| 1372 | * As a partial fix we include pos == apos in a test below. |
| 1373 | */ |
| 1374 | for (k = 0; k < 4; k++) { |
| 1375 | int pos2 = pos + delta[k]; |
| 1376 | if (!ON_BOARD(pos2)) |
| 1377 | continue; |
| 1378 | if ((board[pos] != color || pos == apos) && board[pos2] == EMPTY) { |
| 1379 | ENQUEUE(pos2, dists[pos] + 1); |
| 1380 | } |
| 1381 | else if (board[pos] != other && board[pos2] == other) { |
| 1382 | int stones[MAX_BOARD * MAX_BOARD]; |
| 1383 | int size = findstones(pos2, MAX_BOARD * MAX_BOARD, stones); |
| 1384 | int libs = countlib(pos2); |
| 1385 | int deltadist = libs - 3; |
| 1386 | if (deltadist < 0) |
| 1387 | deltadist = 0; |
| 1388 | for (s = 0; s < size; s++) |
| 1389 | ENQUEUE(stones[s], dists[pos] + deltadist); |
| 1390 | } |
| 1391 | } |
| 1392 | } |
| 1393 | return 1; |
| 1394 | } |
| 1395 | |
| 1396 | /* Initialize an array with atari_atari attacks. The convention is that |
| 1397 | * the array ends when a NO_MOVE is encountered in the move field. |
| 1398 | */ |
| 1399 | static void |
| 1400 | aa_init_moves(struct aa_move attacks[AA_MAX_MOVES]) |
| 1401 | { |
| 1402 | attacks[0].move = NO_MOVE; |
| 1403 | } |
| 1404 | |
| 1405 | |
| 1406 | /* Add an atari_atari attack move to a struct aa_move array. If the |
| 1407 | * move already is included in the array, we check whether the target |
| 1408 | * also is known for that move and add it if not. |
| 1409 | */ |
| 1410 | static void |
| 1411 | aa_add_move(struct aa_move attacks[AA_MAX_MOVES], int move, int target) |
| 1412 | { |
| 1413 | int k; |
| 1414 | int r; |
| 1415 | |
| 1416 | for (k = 0; k < AA_MAX_MOVES; k++) |
| 1417 | if (attacks[k].move == move || attacks[k].move == NO_MOVE) |
| 1418 | break; |
| 1419 | |
| 1420 | /* If the array is full, give up. */ |
| 1421 | if (k == AA_MAX_MOVES) |
| 1422 | return; |
| 1423 | |
| 1424 | target = find_origin(target); |
| 1425 | |
| 1426 | /* New move. */ |
| 1427 | if (attacks[k].move == NO_MOVE) { |
| 1428 | attacks[k].move = move; |
| 1429 | attacks[k].target[0] = target; |
| 1430 | if (AA_MAX_TARGETS_PER_MOVE > 0) |
| 1431 | attacks[k].target[1] = NO_MOVE; |
| 1432 | |
| 1433 | if (k < AA_MAX_MOVES - 1) |
| 1434 | attacks[k+1].move = NO_MOVE; |
| 1435 | |
| 1436 | return; |
| 1437 | } |
| 1438 | |
| 1439 | /* Known move, maybe new target. */ |
| 1440 | for (r = 0; r < AA_MAX_TARGETS_PER_MOVE; r++) |
| 1441 | if (attacks[k].target[r] == target || attacks[k].target[r] == NO_MOVE) |
| 1442 | break; |
| 1443 | |
| 1444 | /* No place for more targets. */ |
| 1445 | if (r == AA_MAX_TARGETS_PER_MOVE) |
| 1446 | return; |
| 1447 | |
| 1448 | /* Target known. */ |
| 1449 | if (attacks[k].target[r] == target) |
| 1450 | return; |
| 1451 | |
| 1452 | /* Add target. */ |
| 1453 | attacks[k].target[r] = target; |
| 1454 | if (r < AA_MAX_TARGETS_PER_MOVE - 1) |
| 1455 | attacks[k].target[r + 1] = NO_MOVE; |
| 1456 | } |
| 1457 | |
| 1458 | /* Check whether an atari_atari attack move is included in an struct |
| 1459 | * aa_move array. If target is not NO_MOVE, we also require that the |
| 1460 | * target is known for the move. |
| 1461 | */ |
| 1462 | static int |
| 1463 | aa_move_known(struct aa_move attacks[AA_MAX_MOVES], int move, int target) |
| 1464 | { |
| 1465 | int k; |
| 1466 | int r; |
| 1467 | |
| 1468 | for (k = 0; k < AA_MAX_MOVES; k++) |
| 1469 | if (attacks[k].move == move || attacks[k].move == NO_MOVE) |
| 1470 | break; |
| 1471 | |
| 1472 | /* If the array is full, give up and claim the move to be known. */ |
| 1473 | if (k == AA_MAX_MOVES) |
| 1474 | return 1; |
| 1475 | |
| 1476 | /* Unknown move. */ |
| 1477 | if (attacks[k].move == NO_MOVE) |
| 1478 | return 0; |
| 1479 | |
| 1480 | /* Move known, but how about the target? |
| 1481 | * If no target specified, just return 1. |
| 1482 | */ |
| 1483 | if (target == NO_MOVE) |
| 1484 | return 1; |
| 1485 | |
| 1486 | target = find_origin(target); |
| 1487 | for (r = 0; r < AA_MAX_TARGETS_PER_MOVE; r++) |
| 1488 | if (attacks[k].target[r] == target || attacks[k].target[r] == NO_MOVE) |
| 1489 | break; |
| 1490 | |
| 1491 | /* No place for more targets. Give up and claim the target to be known. */ |
| 1492 | if (r == AA_MAX_TARGETS_PER_MOVE) |
| 1493 | return 1; |
| 1494 | |
| 1495 | /* Target known. */ |
| 1496 | if (attacks[k].target[r] == target) |
| 1497 | return 1; |
| 1498 | |
| 1499 | /* Unknown target. */ |
| 1500 | return 0; |
| 1501 | } |
| 1502 | |
| 1503 | |
| 1504 | /* Auxiliary function for aa_sort_moves(). */ |
| 1505 | static int |
| 1506 | target_comp_func(const void *a, const void *b) |
| 1507 | { |
| 1508 | int asize = get_aa_value(*((const int *) a)); |
| 1509 | int bsize = get_aa_value(*((const int *) b)); |
| 1510 | return asize - bsize; |
| 1511 | } |
| 1512 | |
| 1513 | |
| 1514 | /* Auxiliary function for aa_sort_moves(). */ |
| 1515 | static int |
| 1516 | move_comp_func(const void *a, const void *b) |
| 1517 | { |
| 1518 | const struct aa_move *aa = a; |
| 1519 | const struct aa_move *bb = b; |
| 1520 | int asize = get_aa_value(aa->target[0]); |
| 1521 | int bsize = get_aa_value(bb->target[0]); |
| 1522 | return asize - bsize; |
| 1523 | } |
| 1524 | |
| 1525 | /* Sort the attack moves. For each move the targets are sorted in |
| 1526 | * decreasing size. Then the moves are sorted with increasing size |
| 1527 | * of their first target. |
| 1528 | */ |
| 1529 | static void |
| 1530 | aa_sort_moves(struct aa_move attacks[AA_MAX_MOVES]) |
| 1531 | { |
| 1532 | int k; |
| 1533 | int r; |
| 1534 | int number_of_attacks; |
| 1535 | int number_of_targets; |
| 1536 | |
| 1537 | for (k = 0; k < AA_MAX_MOVES && attacks[k].move != NO_MOVE; k++) { |
| 1538 | for (r = 0; r < AA_MAX_TARGETS_PER_MOVE; r++) |
| 1539 | if (attacks[k].target[r] == NO_MOVE) |
| 1540 | break; |
| 1541 | number_of_targets = r; |
| 1542 | gg_sort(attacks[k].target, number_of_targets, |
| 1543 | sizeof(attacks[k].target[0]), target_comp_func); |
| 1544 | } |
| 1545 | number_of_attacks = k; |
| 1546 | gg_sort(attacks, number_of_attacks, sizeof(attacks[0]), move_comp_func); |
| 1547 | } |
| 1548 | |
| 1549 | |
| 1550 | #if 0 |
| 1551 | |
| 1552 | /* Returns true if a move by (color) at (pos) is atari on something. |
| 1553 | * Currently unused. |
| 1554 | */ |
| 1555 | |
| 1556 | static int |
| 1557 | is_atari(int pos, int color) |
| 1558 | { |
| 1559 | int other = OTHER_COLOR(color); |
| 1560 | |
| 1561 | if (!is_legal(pos, color)) |
| 1562 | return 0; |
| 1563 | |
| 1564 | if (board[SOUTH(pos)] == other |
| 1565 | && countlib(SOUTH(pos)) == 2) |
| 1566 | return 1; |
| 1567 | |
| 1568 | if (board[WEST(pos)] == other |
| 1569 | && countlib(WEST(pos)) == 2) |
| 1570 | return 1; |
| 1571 | |
| 1572 | if (board[NORTH(pos)] == other |
| 1573 | && countlib(NORTH(pos)) == 2) |
| 1574 | return 1; |
| 1575 | |
| 1576 | if (board[EAST(pos)] == other |
| 1577 | && countlib(EAST(pos)) == 2) |
| 1578 | return 1; |
| 1579 | |
| 1580 | return 0; |
| 1581 | } |
| 1582 | |
| 1583 | #endif |
| 1584 | |
| 1585 | |
| 1586 | /* |
| 1587 | * Local Variables: |
| 1588 | * tab-width: 8 |
| 1589 | * c-basic-offset: 2 |
| 1590 | * End: |
| 1591 | */ |