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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 | #include "gnugo.h" | |
25 | ||
26 | #include <stdio.h> | |
27 | #include <stdlib.h> | |
28 | #include <stdarg.h> | |
29 | #include <string.h> | |
30 | #include <math.h> | |
31 | ||
32 | #include "liberty.h" | |
33 | #include "cache.h" | |
34 | #include "gg_utils.h" | |
35 | #include "readconnect.h" | |
36 | ||
37 | /* Size of array where candidate moves are stored. */ | |
38 | #define MAX_MOVES 362 | |
39 | ||
40 | /* trace of a search */ | |
41 | ||
42 | typedef struct _zone { | |
43 | int array[BOARDMAX]; | |
44 | unsigned int bits[1+BOARDMAX/32]; | |
45 | int i; | |
46 | } zone; | |
47 | ||
48 | static int recursive_connect2(int str1, int str2, int *move, | |
49 | int has_passed); | |
50 | static int recursive_disconnect2(int str1, int str2, int *move, | |
51 | int has_passed); | |
52 | static int recursive_break(int str, const signed char goal[BOARDMAX], | |
53 | int *move, int has_passed, Hash_data *goal_hash); | |
54 | static int recursive_block(int str, const signed char goal[BOARDMAX], | |
55 | int *move, int has_passed, Hash_data *goal_hash); | |
56 | ||
57 | static int add_array(int *array, int elt); | |
58 | static int element_array(int *array, int elt); | |
59 | static void intersection_array(int *array1, int *array2); | |
60 | static int snapback(int str); | |
61 | static int connection_one_move(int str1, int str2); | |
62 | static int prevent_connection_one_move(int *moves, int str1, int str2); | |
63 | static int connected_one_move(int str1, int str2); | |
64 | static int moves_to_connect_in_two_moves(int *moves, int str1, int str2); | |
65 | static int connection_two_moves(int str1, int str2); | |
66 | static int prevent_connection_two_moves(int *moves, int str1, int str2); | |
67 | #if 0 | |
68 | static int connected_two_moves(int str1, int str2); | |
69 | #endif | |
70 | static int moves_to_connect_in_three_moves(int *moves, int str1, int str2, | |
71 | int does_connect); | |
72 | #if 0 | |
73 | static int simple_connection_three_moves(int str1, int str2); | |
74 | static int prevent_simple_connection_three_moves(int *moves, | |
75 | int str1, int str2); | |
76 | #endif | |
77 | ||
78 | static int recursive_connect(int str1, int str2, int *move); | |
79 | static int recursive_disconnect(int str1, int str2, int *move); | |
80 | ||
81 | static int quiescence_connect(int str1, int str2, int *move); | |
82 | static int quiescence_capture(int str, int *move); | |
83 | /* static int capture_one_move(int str); */ | |
84 | static int prevent_capture_one_move(int *moves, int str1); | |
85 | static int recursive_transitivity(int str1, int str2, int str3, int *move); | |
86 | static int recursive_non_transitivity(int str1, int str2, int str3, int *move); | |
87 | static void order_connection_moves(int *moves, int str1, int str2, | |
88 | int color_to_move, const char *funcname); | |
89 | ||
90 | static int nodes_connect = 0; | |
91 | ||
92 | /* Used by alternate connections. */ | |
93 | static signed char connection_shadow[BOARDMAX]; | |
94 | ||
95 | static signed char breakin_shadow[BOARDMAX]; | |
96 | ||
97 | /* Statistics. */ | |
98 | static int global_connection_node_counter = 0; | |
99 | ||
100 | static void | |
101 | init_zone(zone *zn) | |
102 | { | |
103 | zn->array[0] = 0; | |
104 | memset(zn->bits, 0, 1 + BOARDMAX / 8); | |
105 | } | |
106 | ||
107 | /* send back 1 if the intersection is in the zone | |
108 | */ | |
109 | ||
110 | #if 0 | |
111 | static int | |
112 | elt_zone(zone *zn, int elt) | |
113 | { | |
114 | if ((zn->bits[elt >> 5] >> (elt & 31)) & 1) | |
115 | return 1; | |
116 | return 0; | |
117 | } | |
118 | #endif | |
119 | ||
120 | /* Adds an intersection to a zone | |
121 | */ | |
122 | ||
123 | static void | |
124 | add_zone(zone *zn, int elt) | |
125 | { | |
126 | if (((zn->bits[elt >> 5] >> (elt & 31)) & 1) == 0) { | |
127 | zn->bits[elt >> 5] |= (1 << (elt & 31)); | |
128 | zn->array[0]++; | |
129 | zn->array[zn->array[0]] = elt; | |
130 | } | |
131 | } | |
132 | ||
133 | /* start to loop over a zone | |
134 | */ | |
135 | ||
136 | #if 0 | |
137 | static int | |
138 | start_zone(zone *zn) | |
139 | { | |
140 | if (zn->array[0] < 1) | |
141 | return -1; | |
142 | zn->i = 1; | |
143 | return zn->array[1]; | |
144 | } | |
145 | #endif | |
146 | ||
147 | /* continue to loop over a zone | |
148 | */ | |
149 | ||
150 | #if 0 | |
151 | static int | |
152 | next_zone(zone *zn) | |
153 | { | |
154 | zn->i++; | |
155 | if (zn->i > zn->array[0]) | |
156 | return -1; | |
157 | return zn->array[zn->i]; | |
158 | } | |
159 | #endif | |
160 | ||
161 | /* only keep the elements of zn1 which are also in zn2 */ | |
162 | ||
163 | #if 0 | |
164 | static void | |
165 | intersection_zone(zone *zn1, zone *zn2) | |
166 | { | |
167 | int r, s; | |
168 | ||
169 | for (r = start_zone(zn1); r > -1; r = next_zone(zn1)) | |
170 | if (!elt_zone(zn2, r)) { | |
171 | for (s = r; s < zn1->array[0]; s++) | |
172 | zn1->array[s] = zn1->array[s+1]; | |
173 | zn1->bits[r >> 5] &= ~ (1 << (r & 31)); | |
174 | zn1->array[0]--; | |
175 | zn1->i--; | |
176 | } | |
177 | } | |
178 | #endif | |
179 | ||
180 | /* Adds an integer to an array of integers if it is not already there. | |
181 | * The number of elements of the array is in array[0]. | |
182 | */ | |
183 | ||
184 | static int | |
185 | add_array(int *array, int elt) | |
186 | { | |
187 | int r; | |
188 | ||
189 | for (r = 1; r < array[0] + 1; r++) | |
190 | if (array[r] == elt) | |
191 | return 0; | |
192 | ||
193 | array[0]++; | |
194 | array[array[0]] = elt; | |
195 | return 1; | |
196 | } | |
197 | ||
198 | /* test if an element is part of an array */ | |
199 | ||
200 | static int | |
201 | element_array(int *array, int elt) | |
202 | { | |
203 | int r; | |
204 | for (r = 1; r < array[0] + 1; r++) | |
205 | if (array[r] == elt) | |
206 | return 1; | |
207 | return 0; | |
208 | } | |
209 | ||
210 | /* only keep the elements of array1 which are also in array2 */ | |
211 | ||
212 | static void | |
213 | intersection_array(int *array1, int *array2) | |
214 | { | |
215 | int r, s; | |
216 | ||
217 | for (r = 1; r < array1[0] + 1; r++) | |
218 | if (!element_array(array2, array1[r])) { | |
219 | for (s = r; s < array1[0]; s++) | |
220 | array1[s] = array1[s+1]; | |
221 | array1[0]--; | |
222 | r--; | |
223 | } | |
224 | } | |
225 | ||
226 | /* verifies that capturing the stone at str is not a snapback */ | |
227 | ||
228 | static int | |
229 | snapback(int str) | |
230 | { | |
231 | int stones, liberties, lib; | |
232 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
233 | ||
234 | /* if more than one stone captured, not a snapback */ | |
235 | stones = countstones(str); | |
236 | if (stones > 1) | |
237 | return 0; | |
238 | ||
239 | /* if more than one liberty, not a snapback */ | |
240 | liberties = findlib(str, 1, &lib); | |
241 | if (liberties > 1) | |
242 | return 0; | |
243 | ||
244 | /* turn off the sgf traces | |
245 | */ | |
246 | sgf_dumptree = NULL; | |
247 | ||
248 | /* if only one liberty after capture */ | |
249 | if (trymove(lib, OTHER_COLOR(board[str]), "snapback", str)) { | |
250 | liberties = 0; | |
251 | if (IS_STONE(board[lib])) | |
252 | liberties = countlib(lib); | |
253 | popgo(); | |
254 | sgf_dumptree = save_sgf_dumptree; | |
255 | if (liberties > 1) | |
256 | return 0; | |
257 | return WIN; | |
258 | } | |
259 | ||
260 | /* Turn the sgf traces back on. */ | |
261 | sgf_dumptree = save_sgf_dumptree; | |
262 | ||
263 | return 0; | |
264 | } | |
265 | ||
266 | /* connection by playing and finding a ponnuki after play */ | |
267 | ||
268 | static int | |
269 | ponnuki_connect(int *moves, int str1, int str2, zone *zn) | |
270 | { | |
271 | int r, s, k, res = 0; | |
272 | int liberties, libs[MAXLIBS]; | |
273 | int adj, adjs[MAXCHAIN]; | |
274 | int neighb, neighbs[MAXCHAIN]; | |
275 | ||
276 | /* finds connection through two forbidden liberties for | |
277 | * the opponent | |
278 | * + + + + + + + | |
279 | * + + @ O O @ + | |
280 | * + @ + @ @ x + | |
281 | * + + @ + + + + | |
282 | * - - - - - - - | |
283 | * | |
284 | * + + + + + + + | |
285 | * + + @ O O @ + | |
286 | * + @ + @ @ O @ | |
287 | * + + @ + + x + | |
288 | * - - - - - - - | |
289 | */ | |
290 | liberties = findlib(str1, MAXLIBS, libs); | |
291 | for (r = 0; r < liberties; r++) | |
292 | if (is_self_atari(libs[r], OTHER_COLOR(board[str1]))) | |
293 | for (k = 0; k < 4; k++) { | |
294 | int pos = libs[r] + delta[k]; | |
295 | if (board[pos] == board[str1] | |
296 | && !same_string(pos, str1) | |
297 | && !same_string(pos, str2)) { | |
298 | /* try to connect pos to str2 in one move */ | |
299 | /* play a common liberty */ | |
300 | neighb = findlib(pos, MAXLIBS, neighbs); | |
301 | for (s = 0; s < neighb; s++) | |
302 | if (liberty_of_string(neighbs[s], str2)) { | |
303 | res = 1; | |
304 | add_zone(zn, libs[r]); | |
305 | add_zone(zn, neighbs[s]); | |
306 | add_array(moves, neighbs[s]); | |
307 | } | |
308 | /* or capture a common adjacent string */ | |
309 | adj = chainlinks2(pos, adjs, 1); | |
310 | for (s = 0; s < adj; s++) | |
311 | if (adjacent_strings(adjs[s], str2) | |
312 | && !snapback(adjs[s])) { | |
313 | res = 1; | |
314 | neighb = findlib(adjs[s], 1, neighbs); | |
315 | add_zone(zn, libs[r]); | |
316 | add_zone(zn, neighbs[0]); | |
317 | add_array(moves, neighbs[0]); | |
318 | } | |
319 | } | |
320 | } | |
321 | ||
322 | return res; | |
323 | } | |
324 | ||
325 | /* connection in one move, finds all moves and memorizes intersections | |
326 | * involved in the connection. | |
327 | */ | |
328 | ||
329 | static int | |
330 | moves_connection_one_move(int *moves, int str1, int str2, zone *zn) | |
331 | { | |
332 | int r; | |
333 | int adj, adjs[MAXCHAIN]; | |
334 | ||
335 | /* If one string is missing we have already failed. */ | |
336 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
337 | return 0; | |
338 | ||
339 | /* Common liberties. */ | |
340 | if (have_common_lib(str1, str2, NULL)) | |
341 | return WIN; | |
342 | ||
343 | /* Common adjacent string in atari, more than one stone, no snapback. */ | |
344 | adj = chainlinks2(str1, adjs, 1); | |
345 | for (r = 0; r < adj; r++) | |
346 | if (adjacent_strings(adjs[r], str2) | |
347 | && !snapback(adjs[r])) | |
348 | return WIN; | |
349 | ||
350 | /* Connections through a ponnuki */ | |
351 | if (ponnuki_connect(moves, str1, str2, zn)) | |
352 | return WIN; | |
353 | if (ponnuki_connect(moves, str2, str1, zn)) | |
354 | return WIN; | |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
359 | /* Verifies that the strings str1 and str2 can be connected | |
360 | * directly by playing one move, either by playing a common liberty | |
361 | * of the two strings, or by capturing a common adjacent string. | |
362 | * | |
363 | * This is the gi1 game function. | |
364 | */ | |
365 | ||
366 | static int | |
367 | connection_one_move(int str1, int str2) | |
368 | { | |
369 | int moves[BOARDMAX]; | |
370 | zone zn; | |
371 | init_zone(&zn); | |
372 | moves[0] = 0; | |
373 | return moves_connection_one_move(moves, str1, str2, &zn); | |
374 | } | |
375 | ||
376 | /* If the two strings str1 and str2 can be connected sends back WIN fill the | |
377 | * array moves with the only move that can prevent a connection in one move | |
378 | * (common liberties, liberties of common adjacent strings in atari). | |
379 | * | |
380 | * This is the ip1 game function. */ | |
381 | ||
382 | static int | |
383 | prevent_connection_one_move(int *moves, int str1, int str2) | |
384 | { | |
385 | int r, s; | |
386 | int libs[MAXLIBS]; | |
387 | int adj, adjs[MAXCHAIN]; | |
388 | int adjadj, adjadjs[MAXCHAIN]; | |
389 | ||
390 | /* Common liberties. */ | |
391 | if (have_common_lib(str1, str2, libs)) { | |
392 | add_array(moves, libs[0]); | |
393 | return WIN; | |
394 | } | |
395 | ||
396 | /* Save a common adjacent string in atari, more than one stone, no snapback. | |
397 | */ | |
398 | adj = chainlinks2(str1, adjs, 1); | |
399 | for (r = 0; r < adj; r++) | |
400 | if (adjacent_strings(adjs[r], str2) | |
401 | && !snapback(adjs[r])) { | |
402 | findlib(adjs[r], MAXLIBS, libs); | |
403 | add_array(moves, libs[0]); | |
404 | adjadj = chainlinks2(adjs[r], adjadjs, 1); | |
405 | for (s = 0; s < adjadj; s++) { | |
406 | findlib(adjadjs[s], MAXLIBS, libs); | |
407 | add_array(moves, libs[0]); | |
408 | } | |
409 | return WIN; | |
410 | } | |
411 | ||
412 | return 0; | |
413 | } | |
414 | ||
415 | /* Returns WIN if str1 and str2 are connected in at most | |
416 | * one move even if the opponent plays first. | |
417 | * Verify that the strings are connectable in one move | |
418 | * and find the only possible moves that can prevent | |
419 | * using prevent_connection_one_move. If none of these | |
420 | * moves works, the two strings are connected. | |
421 | * | |
422 | * This is the g1 game function. | |
423 | */ | |
424 | ||
425 | static int | |
426 | connected_one_move(int str1, int str2) | |
427 | { | |
428 | int r, res = 0; | |
429 | int moves[MAX_MOVES]; | |
430 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
431 | ||
432 | /* turn off the sgf traces | |
433 | */ | |
434 | sgf_dumptree = NULL; | |
435 | ||
436 | moves[0] = 0; | |
437 | if (prevent_connection_one_move(moves, str1, str2)) { | |
438 | order_connection_moves(moves, str1, str2, OTHER_COLOR(board[str1]), | |
439 | "connected_one_move"); | |
440 | res = WIN; | |
441 | for (r = 1; ((r < moves[0] + 1) && res); r++) { | |
442 | if (trymove(moves[r], OTHER_COLOR(board[str1]), | |
443 | "connected_one_move", str1)) { | |
444 | if (!connection_one_move(str1, str2)) | |
445 | res = 0; | |
446 | popgo(); | |
447 | } | |
448 | } | |
449 | } | |
450 | ||
451 | /* Turn the sgf traces back on. */ | |
452 | sgf_dumptree = save_sgf_dumptree; | |
453 | ||
454 | return res; | |
455 | } | |
456 | ||
457 | /* Find the moves that might be able to connect in less than three plies. | |
458 | * That is moves that can connect the strings if another move of the same | |
459 | * color is played just after: | |
460 | * - common liberties of the two strings; | |
461 | * - moves on the liberties of an opponent string with less than two | |
462 | * liberties adjacent to both strings, or adjacent to one string and | |
463 | * that has a common liberty with the second string; | |
464 | * - liberties of one string that are second order liberties of the | |
465 | * other string. | |
466 | * | |
467 | * Returns WIN if a direct connection has been found. Returns 0 | |
468 | * otherwise. | |
469 | */ | |
470 | ||
471 | static int | |
472 | moves_to_connect_in_two_moves(int *moves, int str1, int str2) | |
473 | { | |
474 | int r, s, common_adj_liberty; | |
475 | int liberties, libs[MAXLIBS]; | |
476 | int adj, adjs[MAXCHAIN]; | |
477 | int adjadj, adjadjs[MAXCHAIN]; | |
478 | int k; | |
479 | int color = board[str1]; | |
480 | int move; | |
481 | ||
482 | /* Common liberties. */ | |
483 | if (have_common_lib(str1, str2, libs)) { | |
484 | add_array(moves, libs[0]); | |
485 | return 1; | |
486 | } | |
487 | ||
488 | /* Capture a common adjacent string or an adjacent liberty of str1 | |
489 | * that has a common liberty with str2... | |
490 | */ | |
491 | adj = chainlinks3(str1, adjs, 2); | |
492 | for (r = 0; r < adj; r++) { | |
493 | liberties = findlib(adjs[r], MAXLIBS, libs); | |
494 | common_adj_liberty = 0; | |
495 | for (s = 0; s < liberties; s++) | |
496 | if (liberty_of_string(libs[s], str2)) | |
497 | common_adj_liberty = 1; | |
498 | if (common_adj_liberty || adjacent_strings(adjs[r], str2)) { | |
499 | for (s = 0; s < liberties; s++) | |
500 | add_array(moves, libs[s]); | |
501 | adjadj = chainlinks2(adjs[r], adjadjs, 1); | |
502 | for (s = 0; s < adjadj; s++) { | |
503 | findlib(adjadjs[s], MAXLIBS, libs); | |
504 | add_array(moves, libs[0]); | |
505 | } | |
506 | } | |
507 | } | |
508 | ||
509 | /* ...and vice versa. */ | |
510 | adj = chainlinks3(str2, adjs, 2); | |
511 | for (r = 0; r < adj; r++) { | |
512 | liberties = findlib(adjs[r], MAXLIBS, libs); | |
513 | common_adj_liberty = 0; | |
514 | for (s = 0; s < liberties; s++) | |
515 | if (liberty_of_string(libs[s], str1)) | |
516 | common_adj_liberty = 1; | |
517 | if (common_adj_liberty || adjacent_strings(adjs[r], str1)) { | |
518 | for (s = 0; s < liberties; s++) | |
519 | add_array(moves, libs[s]); | |
520 | adjadj = chainlinks2(adjs[r], adjadjs, 1); | |
521 | for (s = 0; s < adjadj; s++) { | |
522 | findlib(adjadjs[s], MAXLIBS, libs); | |
523 | add_array(moves, libs[0]); | |
524 | } | |
525 | } | |
526 | } | |
527 | ||
528 | /* Liberties of str1 that are second order liberties of str2 and | |
529 | * vice versa. | |
530 | */ | |
531 | liberties = findlib(str1, MAXLIBS, libs); | |
532 | for (r = 0; r < liberties; r++) { | |
533 | if (board[SOUTH(libs[r])] == EMPTY) { | |
534 | if (liberty_of_string(SOUTH(libs[r]), str2)) { | |
535 | add_array(moves, libs[r]); | |
536 | add_array(moves, SOUTH(libs[r])); | |
537 | } | |
538 | } | |
539 | ||
540 | if (board[WEST(libs[r])] == EMPTY) { | |
541 | if (liberty_of_string(WEST(libs[r]), str2)) { | |
542 | add_array(moves, libs[r]); | |
543 | add_array(moves, WEST(libs[r])); | |
544 | } | |
545 | } | |
546 | ||
547 | if (board[NORTH(libs[r])] == EMPTY) { | |
548 | if (liberty_of_string(NORTH(libs[r]), str2)) { | |
549 | add_array(moves, libs[r]); | |
550 | add_array(moves, NORTH(libs[r])); | |
551 | } | |
552 | } | |
553 | ||
554 | if (board[EAST(libs[r])] == EMPTY) { | |
555 | if (liberty_of_string(EAST(libs[r]), str2)) { | |
556 | add_array(moves, libs[r]); | |
557 | add_array(moves, EAST(libs[r])); | |
558 | } | |
559 | } | |
560 | } | |
561 | ||
562 | /* Liberties of str1 which are adjacent to a friendly string with | |
563 | * common liberty with str2. | |
564 | */ | |
565 | liberties = findlib(str1, MAXLIBS, libs); | |
566 | for (r = 0; r < liberties; r++) { | |
567 | for (k = 0; k < 4; k++) { | |
568 | int pos = libs[r] + delta[k]; | |
569 | if (board[pos] == color | |
570 | && !same_string(pos, str1) | |
571 | && quiescence_connect(pos, str2, &move)) { | |
572 | add_array(moves, libs[r]); | |
573 | add_array(moves, move); | |
574 | } | |
575 | } | |
576 | } | |
577 | ||
578 | /* And vice versa. */ | |
579 | liberties = findlib(str2, MAXLIBS, libs); | |
580 | for (r = 0; r < liberties; r++) { | |
581 | for (k = 0; k < 4; k++) { | |
582 | int pos = libs[r] + delta[k]; | |
583 | if (board[pos] == color | |
584 | && !same_string(pos, str2) | |
585 | && quiescence_connect(pos, str1, &move)) { | |
586 | add_array(moves, libs[r]); | |
587 | add_array(moves, move); | |
588 | } | |
589 | } | |
590 | } | |
591 | ||
592 | return 0; | |
593 | } | |
594 | ||
595 | /* Tests if the strings can be connected in three plies starts | |
596 | * with finding the possible moves that can connect. If two | |
597 | * moves in a row are played, then try them and stops at the | |
598 | * first working move. The strings are connected in two moves | |
599 | * if the function connected_one_move is verified after a move. | |
600 | * | |
601 | * This is the gi2 game function. | |
602 | */ | |
603 | ||
604 | static int | |
605 | connection_two_moves(int str1, int str2) | |
606 | { | |
607 | int r, res = 0, moves[MAX_MOVES]; | |
608 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
609 | ||
610 | /* If one string is missing we have already failed. */ | |
611 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
612 | return 0; | |
613 | ||
614 | moves[0] = 0; | |
615 | if (moves_to_connect_in_two_moves(moves, str1, str2)) | |
616 | return WIN; | |
617 | order_connection_moves(moves, str1, str2, board[str1], | |
618 | "connection_two_moves"); | |
619 | ||
620 | /* turn off the sgf traces | |
621 | */ | |
622 | sgf_dumptree = NULL; | |
623 | ||
624 | for (r = 1; ((r < moves[0] + 1) && !res); r++) { | |
625 | if (trymove(moves[r], board[str1], "connection_two_moves", str1)) { | |
626 | if (connected_one_move(str1, str2)) | |
627 | res = WIN; | |
628 | popgo(); | |
629 | } | |
630 | } | |
631 | ||
632 | sgf_dumptree = save_sgf_dumptree; | |
633 | ||
634 | return res; | |
635 | } | |
636 | ||
637 | /* Find the complete set of possible moves that can prevent | |
638 | * a connection in three plies. | |
639 | * | |
640 | * The function is not yet written, but moves_to_connect_in_two_moves does | |
641 | * a similar job, so it is called temporarly. | |
642 | */ | |
643 | ||
644 | static int | |
645 | moves_to_prevent_connection_in_two_moves(int *moves, int str1, int str2) | |
646 | { | |
647 | if (moves_to_connect_in_two_moves(moves, str1, str2)) | |
648 | return 1; | |
649 | return 0; | |
650 | } | |
651 | ||
652 | /* Find all the moves that prevent to connect in a three plies | |
653 | * deep search and put them in the moves array. Returns 0 if | |
654 | * there is no three plies connection, or else it tries all the | |
655 | * possible preventing moves. If after a possible preventing | |
656 | * moves, there no connection in one move and no connection in | |
657 | * two moves, then the moves prevents a three plies deep | |
658 | * connection, and it is added to the moves array. | |
659 | * | |
660 | * this is the ip2 game function */ | |
661 | ||
662 | static int | |
663 | prevent_connection_two_moves(int *moves, int str1, int str2) | |
664 | { | |
665 | int r, res = 0; | |
666 | int possible_moves[MAX_MOVES]; | |
667 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
668 | ||
669 | /* turn off the sgf traces | |
670 | */ | |
671 | sgf_dumptree = NULL; | |
672 | ||
673 | if (connection_two_moves(str1, str2)) { | |
674 | res = WIN; | |
675 | possible_moves[0] = 0; | |
676 | moves_to_prevent_connection_in_two_moves(possible_moves, str1, str2); | |
677 | order_connection_moves(possible_moves, str1, str2, | |
678 | OTHER_COLOR(board[str1]), | |
679 | "prevent_connection_two_moves"); | |
680 | for (r = 1; r < possible_moves[0] + 1; r++) { | |
681 | if (trymove(possible_moves[r], OTHER_COLOR(board[str1]), | |
682 | "prevent_connection_two_moves", str1)) { | |
683 | if (!connection_one_move(str1, str2)) | |
684 | if (!connection_two_moves(str1, str2)) | |
685 | add_array(moves, possible_moves[r]); | |
686 | popgo(); | |
687 | } | |
688 | } | |
689 | } | |
690 | ||
691 | sgf_dumptree = save_sgf_dumptree; | |
692 | ||
693 | return res; | |
694 | } | |
695 | ||
696 | /* Only partially written. | |
697 | * | |
698 | * Find all the moves than can connect if two subsequent | |
699 | * moves of the same color are played after | |
700 | * - common liberties; | |
701 | * - liberties of common adjacent strings with 3 liberties or less; | |
702 | * - liberties of adjacent strings with 2 liberties or less that have | |
703 | * liberties that are second order liberties of the other string; | |
704 | * - liberties of one string that are second order liberties of the | |
705 | * other string; | |
706 | * - second order liberties of the first string that are second order | |
707 | * liberties of the other string; | |
708 | * | |
709 | * A function that computes the second order liberties of a string is | |
710 | * needed as well as a function that checks efficiently if an | |
711 | * intersection is a second order liberty of a given string. | |
712 | * | |
713 | * If does_connect is 1, generate moves to connect, otherwise generate | |
714 | * moves to disconnect. | |
715 | */ | |
716 | ||
717 | static int | |
718 | moves_to_connect_in_three_moves(int *moves, int str1, int str2, | |
719 | int does_connect) | |
720 | { | |
721 | int r, s; | |
722 | int liberties, libs[MAXLIBS]; | |
723 | int liberties2, libs2[MAXLIBS]; | |
724 | int adj, adjs[MAXCHAIN]; | |
725 | int adjadj, adjadjs[MAXCHAIN]; | |
726 | int move; | |
727 | int k; | |
728 | int pos; | |
729 | int secondlib1[BOARDMAX]; | |
730 | int secondlib2[BOARDMAX]; | |
731 | ||
732 | if (moves_to_connect_in_two_moves(moves, str1, str2)) | |
733 | return 1; | |
734 | ||
735 | /* Find second order liberties of str1. */ | |
736 | memset(secondlib1, 0, sizeof(secondlib1)); | |
737 | liberties = findlib(str1, MAXLIBS, libs); | |
738 | for (r = 0; r < liberties; r++) | |
739 | for (k = 0; k < 4; k++) { | |
740 | pos = libs[r] + delta[k]; | |
741 | if (board[pos] == EMPTY) | |
742 | secondlib1[pos] = 1; | |
743 | else if (board[pos] == board[str1]) { | |
744 | liberties2 = findlib(pos, MAXLIBS, libs2); | |
745 | for (s = 0; s < liberties2; s++) | |
746 | secondlib1[libs2[s]] = 1; | |
747 | } | |
748 | } | |
749 | ||
750 | /* Find second order liberties of str2. | |
751 | */ | |
752 | memset(secondlib2, 0, sizeof(secondlib2)); | |
753 | liberties = findlib(str2, MAXLIBS, libs); | |
754 | for (r = 0; r < liberties; r++) | |
755 | for (k = 0; k < 4; k++) { | |
756 | pos = libs[r] + delta[k]; | |
757 | if (board[pos] == EMPTY) | |
758 | secondlib2[pos] = 1; | |
759 | else if (board[pos] == board[str2]) { | |
760 | liberties2 = findlib(pos, MAXLIBS, libs2); | |
761 | for (s = 0; s < liberties2; s++) | |
762 | secondlib2[libs2[s]] = 1; | |
763 | } | |
764 | } | |
765 | ||
766 | /* Second order liberties of str1 that are second order liberties | |
767 | * of str2 and vice versa. | |
768 | */ | |
769 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
770 | if (secondlib1[pos] && secondlib2[pos]) | |
771 | add_array(moves, pos); | |
772 | } | |
773 | ||
774 | /* Capture a neighbor of str1 which is in atari. The captured string | |
775 | * must in turn have a neighbor which can connect to str2 easily. | |
776 | */ | |
777 | adj = chainlinks2(str1, adjs, 1); | |
778 | for (r = 0; r < adj; r++) { | |
779 | adjadj = chainlinks(adjs[r], adjadjs); | |
780 | for (s = 0; s < adjadj; s++) { | |
781 | if (!same_string(adjadjs[s], str1) | |
782 | && quiescence_connect(adjadjs[s], str2, &move)) { | |
783 | findlib(adjs[r], 1, libs); | |
784 | add_array(moves, libs[0]); | |
785 | add_array(moves, move); | |
786 | } | |
787 | } | |
788 | } | |
789 | ||
790 | /* And vice versa. */ | |
791 | adj = chainlinks2(str2, adjs, 1); | |
792 | for (r = 0; r < adj; r++) { | |
793 | adjadj = chainlinks(adjs[r], adjadjs); | |
794 | for (s = 0; s < adjadj; s++) { | |
795 | if (!same_string(adjadjs[s], str2) | |
796 | && quiescence_connect(adjadjs[s], str1, &move)) { | |
797 | findlib(adjs[r], 1, libs); | |
798 | add_array(moves, libs[0]); | |
799 | add_array(moves, move); | |
800 | } | |
801 | } | |
802 | } | |
803 | ||
804 | /* Liberties of neighbor of str1 with at most two liberties, which | |
805 | * are second order liberties of str2. | |
806 | */ | |
807 | adj = chainlinks3(str1, adjs, 2); | |
808 | for (r = 0; r < adj; r++) { | |
809 | liberties = findlib(adjs[r], 2, libs); | |
810 | for (s = 0; s < liberties; s++) | |
811 | if (second_order_liberty_of_string(libs[s], str2)) | |
812 | add_array(moves, libs[s]); | |
813 | } | |
814 | ||
815 | /* And vice versa. */ | |
816 | adj = chainlinks3(str2, adjs, 2); | |
817 | for (r = 0; r < adj; r++) { | |
818 | liberties = findlib(adjs[r], 2, libs); | |
819 | for (s = 0; s < liberties; s++) | |
820 | if (second_order_liberty_of_string(libs[s], str1)) | |
821 | add_array(moves, libs[s]); | |
822 | } | |
823 | ||
824 | /* Move in on a three liberty opponent string which is adjacent to | |
825 | * str1 and has a liberty in common with str2. | |
826 | */ | |
827 | adj = chainlinks2(str1, adjs, 3); | |
828 | for (r = 0; r < adj; r++) { | |
829 | if (have_common_lib(adjs[r], str2, NULL)) { | |
830 | liberties = findlib(adjs[r], 3, libs); | |
831 | for (s = 0; s < liberties; s++) { | |
832 | /* If generating a connecting move, require the liberty to be | |
833 | * no further than diagonal to a second order liberty of one | |
834 | * of the strings. | |
835 | */ | |
836 | for (k = 0; k < 8; k++) { | |
837 | if (!does_connect | |
838 | || (ON_BOARD(libs[s] + delta[k]) | |
839 | && (secondlib1[libs[s] + delta[k]] | |
840 | || secondlib2[libs[s] + delta[k]]))) { | |
841 | add_array(moves, libs[s]); | |
842 | break; | |
843 | } | |
844 | } | |
845 | } | |
846 | } | |
847 | } | |
848 | ||
849 | /* And vice versa. */ | |
850 | adj = chainlinks2(str2, adjs, 3); | |
851 | for (r = 0; r < adj; r++) { | |
852 | if (have_common_lib(adjs[r], str1, NULL)) { | |
853 | liberties = findlib(adjs[r], 3, libs); | |
854 | for (s = 0; s < liberties; s++) { | |
855 | /* If generating a connecting move, require the liberty to be | |
856 | * no further than diagonal to a second order liberty of one | |
857 | * of the strings. | |
858 | */ | |
859 | for (k = 0; k < 8; k++) { | |
860 | if (!does_connect | |
861 | || (ON_BOARD(libs[s] + delta[k]) | |
862 | && (secondlib1[libs[s] + delta[k]] | |
863 | || secondlib2[libs[s] + delta[k]]))) { | |
864 | add_array(moves, libs[s]); | |
865 | break; | |
866 | } | |
867 | } | |
868 | } | |
869 | } | |
870 | } | |
871 | ||
872 | return 0; | |
873 | } | |
874 | ||
875 | ||
876 | /* Not yet written. | |
877 | * | |
878 | * Find the complete set of possible moves that can prevent | |
879 | * a connection in 5 plies. | |
880 | */ | |
881 | ||
882 | static int | |
883 | moves_to_prevent_connection_in_three_moves(int *moves, int str1, int str2) | |
884 | { | |
885 | if (moves_to_connect_in_three_moves(moves, str1, str2, 0)) | |
886 | return 1; | |
887 | return 0; | |
888 | } | |
889 | ||
890 | /* | |
891 | * The simplest depth 4 connection: | |
892 | * | |
893 | * If there are forced moves to prevent connection in one move, | |
894 | * try them, and verify that they all lead to a depth 1 or | |
895 | * depth 3 connection. | |
896 | * | |
897 | * This is the g211 game function. | |
898 | */ | |
899 | ||
900 | static int | |
901 | simply_connected_two_moves(int str1, int str2) | |
902 | { | |
903 | int r, res = 0; | |
904 | int moves[MAX_MOVES]; | |
905 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
906 | ||
907 | /* turn off the sgf traces | |
908 | */ | |
909 | sgf_dumptree = NULL; | |
910 | ||
911 | ||
912 | /* If one string is missing we have already failed. */ | |
913 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
914 | return 0; | |
915 | ||
916 | moves[0] = 0; | |
917 | if (prevent_connection_one_move(moves, str1, str2)) { | |
918 | res = WIN; | |
919 | order_connection_moves(moves, str1, str2, OTHER_COLOR(board[str1]), | |
920 | "simply_connected_two_moves"); | |
921 | for (r = 1; ((r < moves[0] + 1) && res); r++) { | |
922 | if (trymove(moves[r], OTHER_COLOR(board[str1]), | |
923 | "simply_connected_two_moves", str1)) { | |
924 | if (!connection_one_move(str1, str2)) | |
925 | if (!connection_two_moves(str1, str2)) | |
926 | res = 0; | |
927 | popgo(); | |
928 | } | |
929 | } | |
930 | } | |
931 | ||
932 | sgf_dumptree = save_sgf_dumptree; | |
933 | ||
934 | return res; | |
935 | } | |
936 | ||
937 | /* Test if a move is a simple depth 5 connection. | |
938 | * | |
939 | * This is the gi311 game function. | |
940 | */ | |
941 | ||
942 | static int | |
943 | simple_connection_three_moves(int str1, int str2) | |
944 | { | |
945 | int r, res = 0, moves[MAX_MOVES]; | |
946 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
947 | ||
948 | /* turn off the sgf traces | |
949 | */ | |
950 | sgf_dumptree = NULL; | |
951 | ||
952 | ||
953 | moves[0] = 0; | |
954 | if (moves_to_connect_in_two_moves(moves, str1, str2)) | |
955 | return WIN; | |
956 | order_connection_moves(moves, str1, str2, board[str1], | |
957 | "simple_connection_three_moves"); | |
958 | for (r = 1; ((r < moves[0] + 1) && !res); r++) { | |
959 | if (trymove(moves[r], board[str1], | |
960 | "simple_connection_three_moves", str1)) { | |
961 | if (simply_connected_two_moves(str1, str2)) | |
962 | res = WIN; | |
963 | popgo(); | |
964 | } | |
965 | } | |
966 | ||
967 | sgf_dumptree = save_sgf_dumptree; | |
968 | ||
969 | return res; | |
970 | } | |
971 | ||
972 | /* Find the forced moves that prevent a simple depth 5 connection. | |
973 | * Fills the array moves with the forced moves. | |
974 | * | |
975 | * This is the ip311 game function. | |
976 | * | |
977 | * It finds moves in very important situations such as: | |
978 | * | |
979 | * + + + O + + | |
980 | * + @ @ O + + | |
981 | * + @ O @ @ + | |
982 | * + @ O + + + | |
983 | * + + + + + + | |
984 | * - - - - - - | |
985 | * | |
986 | * and enables recursive_disconnect to prove the two black | |
987 | * strings are connected in these situations. | |
988 | */ | |
989 | ||
990 | static int | |
991 | prevent_simple_connection_three_moves(int *moves, int str1, int str2) | |
992 | { | |
993 | int r, res = 0; | |
994 | int possible_moves[MAX_MOVES]; | |
995 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
996 | ||
997 | /* turn off the sgf traces | |
998 | */ | |
999 | sgf_dumptree = NULL; | |
1000 | ||
1001 | ||
1002 | if (simple_connection_three_moves(str1, str2)) { | |
1003 | res = WIN; | |
1004 | possible_moves[0] = 0; | |
1005 | moves_to_prevent_connection_in_three_moves(possible_moves, str1, str2); | |
1006 | order_connection_moves(moves, str1, str2, OTHER_COLOR(board[str1]), | |
1007 | "prevent_simple_connection_three_moves"); | |
1008 | for (r = 1; r < possible_moves[0] + 1; r++) { | |
1009 | if (trymove(possible_moves[r], OTHER_COLOR(board[str1]), | |
1010 | "prevent_simple_connection_three_moves", str1)) { | |
1011 | if (!connection_one_move(str1, str2)) | |
1012 | if (!connection_two_moves(str1, str2)) | |
1013 | if (!simple_connection_three_moves(str1, str2)) | |
1014 | add_array(moves, possible_moves[r]); | |
1015 | popgo(); | |
1016 | } | |
1017 | } | |
1018 | } | |
1019 | ||
1020 | sgf_dumptree = save_sgf_dumptree; | |
1021 | ||
1022 | return res; | |
1023 | } | |
1024 | ||
1025 | /* Find simple connections by looking at common liberties | |
1026 | * or directly capturing a common adjacent string without a snapback | |
1027 | * or looking at a ladder for a common adjacent string. | |
1028 | */ | |
1029 | ||
1030 | static int | |
1031 | quiescence_connect(int str1, int str2, int *move) | |
1032 | { | |
1033 | int r; | |
1034 | int lib; | |
1035 | int adj, adjs[MAXCHAIN]; | |
1036 | ||
1037 | /* Common liberties. */ | |
1038 | if (have_common_lib(str1, str2, &lib)) { | |
1039 | *move = lib; | |
1040 | return WIN; | |
1041 | } | |
1042 | ||
1043 | /* Common adjacent string in atari, more than one stone, no snapback. */ | |
1044 | adj = chainlinks2(str1, adjs, 1); | |
1045 | for (r = 0; r < adj; r++) | |
1046 | if (adjacent_strings(adjs[r], str2) | |
1047 | && !snapback(adjs[r])) { | |
1048 | findlib(adjs[r], 1, move); | |
1049 | return WIN; | |
1050 | } | |
1051 | ||
1052 | /* Common adjacent string two liberties, read ladder. */ | |
1053 | adj = chainlinks2(str1, adjs, 2); | |
1054 | for (r = 0; r < adj; r++) | |
1055 | if (adjacent_strings(adjs[r], str2)) | |
1056 | if (quiescence_capture(adjs[r], move)) | |
1057 | return WIN; | |
1058 | ||
1059 | return 0; | |
1060 | } | |
1061 | ||
1062 | ||
1063 | /* A persistent connection cache has been implemented, but currently | |
1064 | * (3.3.15) it does not have much impact on performance. Possible | |
1065 | * explanations for this include: | |
1066 | * 1. The active area is too often unnecessarily large. | |
1067 | * 2. Between the persistent caches of tactical reading and owl | |
1068 | * reading, there is not much to gain from also caching the | |
1069 | * connection results. | |
1070 | * 3. There is some bug in the implementation. | |
1071 | * | |
1072 | * In order to simplify testing of code modifications, the caching | |
1073 | * code has been made conditional. Setting | |
1074 | * USE_PERSISTENT_CONNECTION_CACHE to 0, 1, or 2 has the following | |
1075 | * effects. | |
1076 | * 0 - Completely turned off. | |
1077 | * 1 - Results are stored in the cache but retrieved results are only | |
1078 | * compared to the non-cached result. Deviations are reported. | |
1079 | * 2 - Fully turned on. | |
1080 | */ | |
1081 | #define USE_PERSISTENT_CONNECTION_CACHE 0 | |
1082 | ||
1083 | ||
1084 | /* Externally callable frontend to recursive_connect(). | |
1085 | * Returns WIN if str1 and str2 can be connected. | |
1086 | */ | |
1087 | int | |
1088 | string_connect(int str1, int str2, int *move) | |
1089 | { | |
1090 | int dummy_move; | |
1091 | int save_verbose; | |
1092 | int result; | |
1093 | ||
1094 | if (move == NULL) | |
1095 | move = &dummy_move; | |
1096 | ||
1097 | nodes_connect = 0; | |
1098 | *move = PASS_MOVE; | |
1099 | ||
1100 | if (alternate_connections) { | |
1101 | int reading_nodes_when_called = get_reading_node_counter(); | |
1102 | double start = 0; | |
1103 | int tactical_nodes; | |
1104 | int save_connection_node_limit = connection_node_limit; | |
1105 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1106 | int result2 = -1; | |
1107 | int move2; | |
1108 | #endif | |
1109 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
1110 | return 0; | |
1111 | str1 = find_origin(str1); | |
1112 | str2 = find_origin(str2); | |
1113 | if (str1 > str2) { | |
1114 | int tmp = str1; | |
1115 | str1 = str2; | |
1116 | str2 = tmp; | |
1117 | } | |
1118 | ||
1119 | ||
1120 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1121 | if (!search_persistent_connection_cache(CONNECT, str1, str2, | |
1122 | &result2, &move2)) | |
1123 | result2 = -1; | |
1124 | else if (0) | |
1125 | gprintf("Persistent cache found connect %1m %1m: %d %1m\n", | |
1126 | str1, str2, result2, move2); | |
1127 | #endif | |
1128 | #if USE_PERSISTENT_CONNECTION_CACHE == 2 | |
1129 | if (search_persistent_connection_cache(CONNECT, str1, str2, &result, move)) | |
1130 | return result; | |
1131 | #endif | |
1132 | ||
1133 | connection_node_limit *= pow(1.45, -stackp + get_depth_modification()); | |
1134 | save_verbose = verbose; | |
1135 | if (verbose > 0) | |
1136 | verbose--; | |
1137 | start = gg_cputime(); | |
1138 | memset(connection_shadow, 0, sizeof(connection_shadow)); | |
1139 | result = recursive_connect2(str1, str2, move, 0); | |
1140 | verbose = save_verbose; | |
1141 | tactical_nodes = get_reading_node_counter() - reading_nodes_when_called; | |
1142 | connection_node_limit = save_connection_node_limit; | |
1143 | ||
1144 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1145 | if (result2 != -1 | |
1146 | && result2 != result | |
1147 | && *move != move2) | |
1148 | gprintf("Persistent cache failure connect %1m %1m: %d %1m != %d %1m\n", | |
1149 | str1, str2, result, *move, result2, move2); | |
1150 | #endif | |
1151 | ||
1152 | if (0) { | |
1153 | gprintf("%oconnect %1M %1M, result %d %1M (%d, %d nodes, %f seconds)\n", | |
1154 | str1, str2, result, *move, | |
1155 | nodes_connect, tactical_nodes, gg_cputime() - start); | |
1156 | dump_stack(); | |
1157 | } | |
1158 | if (0) { | |
1159 | gprintf("%oconnect %1m %1m %d %1m ", str1, str2, result, *move); | |
1160 | dump_stack(); | |
1161 | } | |
1162 | ||
1163 | #if USE_PERSISTENT_CONNECTION_CACHE > 0 | |
1164 | store_persistent_connection_cache(CONNECT, str1, str2, result, *move, | |
1165 | tactical_nodes, connection_shadow); | |
1166 | #endif | |
1167 | ||
1168 | return result; | |
1169 | } | |
1170 | ||
1171 | return recursive_connect(str1, str2, move); | |
1172 | } | |
1173 | ||
1174 | ||
1175 | /* returns WIN if str1 and str2 can be connected. */ | |
1176 | ||
1177 | static int | |
1178 | recursive_connect(int str1, int str2, int *move) | |
1179 | { | |
1180 | int i, res = 0, Moves[MAX_MOVES], ForcedMoves[MAX_MOVES]; | |
1181 | SETUP_TRACE_INFO2("recursive_connect", str1, str2); | |
1182 | ||
1183 | if (board[str1] == EMPTY || board[str2] == EMPTY) { | |
1184 | SGFTRACE2(PASS_MOVE, 0, "one string already captured"); | |
1185 | return 0; | |
1186 | } | |
1187 | ||
1188 | if (same_string(str1, str2)) { | |
1189 | SGFTRACE2(PASS_MOVE, WIN, "already connected"); | |
1190 | return WIN; | |
1191 | } | |
1192 | ||
1193 | if (nodes_connect > connection_node_limit) { | |
1194 | SGFTRACE2(PASS_MOVE, 0, "connection node limit reached"); | |
1195 | return 0; | |
1196 | } | |
1197 | ||
1198 | if (stackp == connect_depth) { | |
1199 | SGFTRACE2(PASS_MOVE, 0, "connection depth limit reached"); | |
1200 | return 0; | |
1201 | } | |
1202 | ||
1203 | nodes_connect++; | |
1204 | global_connection_node_counter++; | |
1205 | ||
1206 | if (quiescence_connect (str1, str2, move)) { | |
1207 | SGFTRACE2(*move, WIN, "quiescence_connect"); | |
1208 | return WIN; | |
1209 | } | |
1210 | ||
1211 | ForcedMoves[0] = 0; | |
1212 | Moves[0] = 0; | |
1213 | /* if one of the strings to connect can be captured | |
1214 | * and there are forced moves to prevent the capture | |
1215 | * then the only moves to try are the moves that | |
1216 | * defend the string: all the other moves will | |
1217 | * lead to the capture of the string | |
1218 | */ | |
1219 | if (!prevent_capture_one_move(ForcedMoves, str1)) | |
1220 | prevent_capture_one_move(ForcedMoves, str2); | |
1221 | #if 0 | |
1222 | else if (prevent_capture_two_moves(ForcedMoves, str1)) | |
1223 | ; | |
1224 | else if (prevent_capture_two_moves(ForcedMoves, str2)) | |
1225 | ; | |
1226 | #endif | |
1227 | ||
1228 | /* We are at a max node, so any move we can find | |
1229 | * is ok. Try moves that can connect in three moves | |
1230 | * because the function that prevent connection in one | |
1231 | * and two moves are called at AND nodes. | |
1232 | */ | |
1233 | moves_to_connect_in_three_moves(Moves, str1, str2, 1); | |
1234 | ||
1235 | /* if there are some forced moves to prevent the capture | |
1236 | * of one of the two strings, then we only look at | |
1237 | * the moves that prevent capture and that might also | |
1238 | * connect | |
1239 | */ | |
1240 | if (ForcedMoves[0] != 0 && Moves[0] != 0) | |
1241 | intersection_array(Moves, ForcedMoves); | |
1242 | ||
1243 | order_connection_moves(Moves, str1, str2, board[str1], | |
1244 | "recursive_connect"); | |
1245 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) { | |
1246 | if (trymove(Moves[i], board[str1], "recursive_connect", str1)) { | |
1247 | if (!recursive_disconnect(str1, str2, move)) { | |
1248 | *move = Moves[i]; | |
1249 | res = WIN; | |
1250 | } | |
1251 | popgo(); | |
1252 | } | |
1253 | } | |
1254 | ||
1255 | if (res == WIN) { | |
1256 | SGFTRACE2(*move, WIN, "success"); | |
1257 | } | |
1258 | else { | |
1259 | SGFTRACE2(PASS_MOVE, 0, "failure"); | |
1260 | } | |
1261 | ||
1262 | return res; | |
1263 | } | |
1264 | ||
1265 | ||
1266 | /* Externally callable frontend to recursive_disconnect(). | |
1267 | * Returns WIN if str1 and str2 can be disconnected. | |
1268 | */ | |
1269 | int | |
1270 | disconnect(int str1, int str2, int *move) | |
1271 | { | |
1272 | int i; | |
1273 | int res = WIN; | |
1274 | int Moves[MAX_MOVES]; | |
1275 | int dummy_move; | |
1276 | int result; | |
1277 | int save_verbose; | |
1278 | ||
1279 | if (move == NULL) | |
1280 | move = &dummy_move; | |
1281 | ||
1282 | nodes_connect = 0; | |
1283 | *move = PASS_MOVE; | |
1284 | ||
1285 | if (alternate_connections) { | |
1286 | int reading_nodes_when_called = get_reading_node_counter(); | |
1287 | int save_connection_node_limit = connection_node_limit; | |
1288 | double start = 0; | |
1289 | int tactical_nodes; | |
1290 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1291 | int result2 = -1; | |
1292 | int move2; | |
1293 | #endif | |
1294 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
1295 | return WIN; | |
1296 | str1 = find_origin(str1); | |
1297 | str2 = find_origin(str2); | |
1298 | if (str1 > str2) { | |
1299 | int tmp = str1; | |
1300 | str1 = str2; | |
1301 | str2 = tmp; | |
1302 | } | |
1303 | ||
1304 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1305 | if (!search_persistent_connection_cache(DISCONNECT, str1, str2, | |
1306 | &result2, &move2)) | |
1307 | result2 = -1; | |
1308 | else if (0) | |
1309 | gprintf("Persistent cache found disconnect %1m %1m: %d %1m\n", | |
1310 | str1, str2, result2, move2); | |
1311 | #endif | |
1312 | #if USE_PERSISTENT_CONNECTION_CACHE == 2 | |
1313 | if (search_persistent_connection_cache(DISCONNECT, str1, str2, | |
1314 | &result, move)) | |
1315 | return result; | |
1316 | #endif | |
1317 | ||
1318 | connection_node_limit *= pow(1.5, -stackp + get_depth_modification()); | |
1319 | save_verbose = verbose; | |
1320 | if (verbose > 0) | |
1321 | verbose--; | |
1322 | start = gg_cputime(); | |
1323 | memset(connection_shadow, 0, sizeof(connection_shadow)); | |
1324 | result = recursive_disconnect2(str1, str2, move, 0); | |
1325 | verbose = save_verbose; | |
1326 | tactical_nodes = get_reading_node_counter() - reading_nodes_when_called; | |
1327 | connection_node_limit = save_connection_node_limit; | |
1328 | ||
1329 | #if USE_PERSISTENT_CONNECTION_CACHE == 1 | |
1330 | if (result2 != -1 | |
1331 | && result2 != result | |
1332 | && *move != move2) | |
1333 | gprintf("Persistent cache failure disconnect %1m %1m: %d %1m != %d %1m\n", | |
1334 | str1, str2, result, *move, result2, move2); | |
1335 | #endif | |
1336 | ||
1337 | if (0) { | |
1338 | gprintf("%odisconnect %1m %1m, result %d %1m (%d, %d nodes, %f seconds)\n", | |
1339 | str1, str2, result, *move, | |
1340 | nodes_connect, tactical_nodes, gg_cputime() - start); | |
1341 | dump_stack(); | |
1342 | } | |
1343 | if (0) { | |
1344 | gprintf("%odisconnect %1m %1m %d %1m ", str1, str2, result, *move); | |
1345 | dump_stack(); | |
1346 | } | |
1347 | ||
1348 | #if USE_PERSISTENT_CONNECTION_CACHE > 0 | |
1349 | store_persistent_connection_cache(DISCONNECT, str1, str2, result, *move, | |
1350 | tactical_nodes, connection_shadow); | |
1351 | #endif | |
1352 | ||
1353 | return result; | |
1354 | } | |
1355 | ||
1356 | Moves[0] = 0; | |
1357 | moves_to_prevent_connection_in_three_moves(Moves, str1, str2); | |
1358 | if (Moves[0] > 0) | |
1359 | res = 0; | |
1360 | order_connection_moves(Moves, str1, str2, OTHER_COLOR(board[str1]), | |
1361 | "disconnect"); | |
1362 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) | |
1363 | if (trymove(Moves[i], OTHER_COLOR(board[str1]), | |
1364 | "disconnect", str1)) { | |
1365 | if (!recursive_connect(str1, str2, move)) { | |
1366 | *move = Moves[i]; | |
1367 | res = WIN; | |
1368 | } | |
1369 | popgo(); | |
1370 | } | |
1371 | return res; | |
1372 | } | |
1373 | ||
1374 | /* Externally callable frontend to recursive_disconnect(). | |
1375 | * Returns WIN if str1 and str2 can be disconnected. | |
1376 | * | |
1377 | * Uses much lower node and depths limits. | |
1378 | */ | |
1379 | int | |
1380 | fast_disconnect(int str1, int str2, int *move) | |
1381 | { | |
1382 | int result; | |
1383 | int save_limit = connection_node_limit; | |
1384 | int save_verbose = verbose; | |
1385 | ||
1386 | if (board[str1] == EMPTY || board[str2] == EMPTY) | |
1387 | return WIN; | |
1388 | str1 = find_origin(str1); | |
1389 | str2 = find_origin(str2); | |
1390 | if (str1 > str2) { | |
1391 | int tmp = str1; | |
1392 | str1 = str2; | |
1393 | str2 = tmp; | |
1394 | } | |
1395 | ||
1396 | modify_depth_values(-3); | |
1397 | connection_node_limit /= 4; | |
1398 | ||
1399 | if (verbose > 0) | |
1400 | verbose--; | |
1401 | result = recursive_disconnect2(str1, str2, move, 0); | |
1402 | verbose = save_verbose; | |
1403 | ||
1404 | connection_node_limit = save_limit; | |
1405 | modify_depth_values(3); | |
1406 | ||
1407 | return result; | |
1408 | } | |
1409 | ||
1410 | ||
1411 | ||
1412 | /* Returns WIN if str1 and str2 can be disconnected. */ | |
1413 | ||
1414 | static int | |
1415 | recursive_disconnect(int str1, int str2, int *move) | |
1416 | { | |
1417 | int i, res = WIN, Moves[MAX_MOVES]; | |
1418 | ||
1419 | SETUP_TRACE_INFO2("recursive_disconnect", str1, str2); | |
1420 | ||
1421 | if (board[str1] == EMPTY || board[str2] == EMPTY) { | |
1422 | SGFTRACE2(PASS_MOVE, WIN, "one string already captured"); | |
1423 | return WIN; | |
1424 | } | |
1425 | ||
1426 | if (quiescence_capture(str1, move)) { | |
1427 | SGFTRACE2(*move, WIN, "first string capturable"); | |
1428 | return WIN; | |
1429 | } | |
1430 | if (quiescence_capture(str2, move)) { | |
1431 | SGFTRACE2(*move, WIN, "second string capturable"); | |
1432 | return WIN; | |
1433 | } | |
1434 | ||
1435 | if (same_string(str1, str2)) { | |
1436 | SGFTRACE2(PASS_MOVE, 0, "already connected"); | |
1437 | return 0; | |
1438 | } | |
1439 | ||
1440 | if (nodes_connect > connection_node_limit) { | |
1441 | SGFTRACE2(PASS_MOVE, WIN, "connection node limit reached"); | |
1442 | return WIN; | |
1443 | } | |
1444 | ||
1445 | if (stackp == connect_depth) { | |
1446 | SGFTRACE2(PASS_MOVE, WIN, "connection depth limit reached"); | |
1447 | return WIN; | |
1448 | } | |
1449 | ||
1450 | nodes_connect++; | |
1451 | global_connection_node_counter++; | |
1452 | ||
1453 | /* we are at an and node | |
1454 | * only look at forced moves here, | |
1455 | * it ensures that the result of recursive_disconnect | |
1456 | * is proved if it returns 0 (that is connections are proved) | |
1457 | */ | |
1458 | Moves[0] = 0; | |
1459 | ||
1460 | if (prevent_connection_one_move(Moves, str1, str2)) | |
1461 | res = 0; | |
1462 | else if (prevent_connection_two_moves(Moves, str1, str2)) | |
1463 | res = 0; | |
1464 | else if (prevent_simple_connection_three_moves(Moves, str1, str2)) | |
1465 | res = 0; | |
1466 | ||
1467 | if (res == 0) | |
1468 | order_connection_moves(Moves, str1, str2, OTHER_COLOR(board[str1]), | |
1469 | "recursive_disconnect"); | |
1470 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) | |
1471 | if (trymove(Moves[i], OTHER_COLOR(board[str1]), | |
1472 | "recursive_disconnect", str1)) { | |
1473 | if (!recursive_connect(str1, str2, move)) { | |
1474 | *move = Moves[i]; | |
1475 | res = WIN; | |
1476 | } | |
1477 | popgo(); | |
1478 | } | |
1479 | ||
1480 | if (res == WIN) { | |
1481 | SGFTRACE2(*move, WIN, "success"); | |
1482 | } | |
1483 | else { | |
1484 | SGFTRACE2(PASS_MOVE, 0, "failure"); | |
1485 | } | |
1486 | ||
1487 | return res; | |
1488 | } | |
1489 | ||
1490 | /* Reads simple ladders. | |
1491 | */ | |
1492 | ||
1493 | static int | |
1494 | quiescence_capture(int str, int *move) | |
1495 | { | |
1496 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
1497 | int save_count_variations = count_variations; | |
1498 | int result = 0; | |
1499 | ||
1500 | /* We turn off the sgf traces here to avoid cluttering them up with | |
1501 | * naive_ladder moves. | |
1502 | */ | |
1503 | sgf_dumptree = NULL; | |
1504 | count_variations = 0; | |
1505 | ||
1506 | if (countlib(str) == 1) { | |
1507 | findlib(str, 1, move); | |
1508 | result = WIN; | |
1509 | } | |
1510 | else if (countlib(str) == 2) | |
1511 | result = simple_ladder(str, move); | |
1512 | ||
1513 | /* Turn the sgf traces back on. */ | |
1514 | sgf_dumptree = save_sgf_dumptree; | |
1515 | count_variations = save_count_variations; | |
1516 | ||
1517 | return result; | |
1518 | } | |
1519 | ||
1520 | #if 0 | |
1521 | static int | |
1522 | capture_one_move(int str) | |
1523 | { | |
1524 | if (countlib(str) == 1) | |
1525 | return 1; | |
1526 | return 0; | |
1527 | } | |
1528 | #endif | |
1529 | ||
1530 | /* Find all the possible moves that can prevent the capture | |
1531 | * of a string in atari. | |
1532 | * | |
1533 | * The ip1 game function. | |
1534 | */ | |
1535 | ||
1536 | static int | |
1537 | prevent_capture_one_move(int *moves, int str1) | |
1538 | { | |
1539 | int r, res = 0; | |
1540 | int liberties, libs[MAXLIBS]; | |
1541 | int adj, adjs[MAXCHAIN]; | |
1542 | ||
1543 | liberties = findlib(str1, MAXLIBS, libs); | |
1544 | if (liberties == 1) { | |
1545 | add_array(moves, libs[0]); | |
1546 | res = WIN; | |
1547 | adj = chainlinks2(str1, adjs, 1); | |
1548 | for (r = 0; r < adj; r++) { | |
1549 | findlib(adjs[r], 1, libs); | |
1550 | add_array(moves, libs[0]); | |
1551 | } | |
1552 | } | |
1553 | return res; | |
1554 | } | |
1555 | ||
1556 | ||
1557 | /* Returns WIN if str1, str2 and str3 can be connected. */ | |
1558 | ||
1559 | static int | |
1560 | recursive_transitivity(int str1, int str2, int str3, int *move) | |
1561 | { | |
1562 | int i, res = 0, Moves[MAX_MOVES], ForcedMoves[MAX_MOVES]; | |
1563 | ||
1564 | SETUP_TRACE_INFO2("recursive_transitivity", str1, str3); | |
1565 | ||
1566 | if (board[str1] == EMPTY || board[str2] == EMPTY || board[str3] == EMPTY) { | |
1567 | SGFTRACE2(PASS_MOVE, 0, "one string already captured"); | |
1568 | return 0; | |
1569 | } | |
1570 | ||
1571 | if (same_string(str1, str2) && same_string(str1, str3)) { | |
1572 | SGFTRACE2(PASS_MOVE, WIN, "already connected"); | |
1573 | return WIN; | |
1574 | } | |
1575 | ||
1576 | if (nodes_connect > connection_node_limit) { | |
1577 | SGFTRACE2(PASS_MOVE, 0, "connection node limit reached"); | |
1578 | return 0; | |
1579 | } | |
1580 | ||
1581 | if (stackp == connect_depth) { | |
1582 | SGFTRACE2(PASS_MOVE, 0, "connection depth limit reached"); | |
1583 | return 0; | |
1584 | } | |
1585 | ||
1586 | nodes_connect++; | |
1587 | global_connection_node_counter++; | |
1588 | ||
1589 | if (same_string(str1, str2)) | |
1590 | if (quiescence_connect (str1, str3, move)) { | |
1591 | SGFTRACE2(*move, WIN, "quiescence_connect"); | |
1592 | return WIN; | |
1593 | } | |
1594 | ||
1595 | if (same_string(str2, str3)) | |
1596 | if (quiescence_connect (str1, str2, move)) { | |
1597 | SGFTRACE2(*move, WIN, "quiescence_connect"); | |
1598 | return WIN; | |
1599 | } | |
1600 | ||
1601 | ForcedMoves[0] = 0; | |
1602 | Moves[0] = 0; | |
1603 | /* If one of the strings to connect can be captured | |
1604 | * and there are forced moves to prevent the capture | |
1605 | * then the only moves to try are the moves that | |
1606 | * defend the string. All the other moves will | |
1607 | * lead to the capture of the string. | |
1608 | */ | |
1609 | if (!prevent_capture_one_move(ForcedMoves, str1)) | |
1610 | if (!prevent_capture_one_move(ForcedMoves, str2)) | |
1611 | prevent_capture_one_move(ForcedMoves, str3); | |
1612 | ||
1613 | /* We are at a max node, so any move we can find | |
1614 | * is ok. Try moves that can connect in two moves | |
1615 | * because the function that prevents connection in one | |
1616 | * move is called at and nodes. | |
1617 | */ | |
1618 | moves_to_connect_in_two_moves(Moves, str1, str2); | |
1619 | moves_to_connect_in_two_moves(Moves, str2, str3); | |
1620 | ||
1621 | /* If there are some forced moves to prevent the capture | |
1622 | * of one of the two strings, then we only look at | |
1623 | * the moves that prevent capture and that might also | |
1624 | * connect. | |
1625 | */ | |
1626 | if ((ForcedMoves[0] != 0) && (Moves[0] != 0)) | |
1627 | intersection_array(Moves, ForcedMoves); | |
1628 | ||
1629 | order_connection_moves(Moves, str1, str2, board[str1], | |
1630 | "recursive_transitivity"); | |
1631 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) { | |
1632 | if (trymove(Moves[i], board[str1], "recursive_transitivity", str1)) { | |
1633 | if (!recursive_non_transitivity(str1, str2, str3, move)) { | |
1634 | *move = Moves[i]; | |
1635 | res = WIN; | |
1636 | } | |
1637 | popgo(); | |
1638 | } | |
1639 | } | |
1640 | ||
1641 | if (res == WIN) { | |
1642 | SGFTRACE2(*move, WIN, "success"); | |
1643 | } | |
1644 | else { | |
1645 | SGFTRACE2(PASS_MOVE, 0, "failure"); | |
1646 | } | |
1647 | ||
1648 | return res; | |
1649 | } | |
1650 | ||
1651 | /* It is often assumed that if str1 connects to str2 and str2 | |
1652 | * connects to str3 then str1 connects to str3. This is called | |
1653 | * TRANSITIVITY. However there are exceptions such as this | |
1654 | * situation: | |
1655 | * | |
1656 | * XXXXX XXXXX | |
1657 | * OO.OO AA*CC | |
1658 | * ..O.. ..B.. | |
1659 | * XXXXX XXXXX | |
1660 | * | |
1661 | * Although strings A and B are connected, and strings B and C | |
1662 | * are connected, a move at * disconnects strings A and C. | |
1663 | * | |
1664 | * This function is a public frontend to recursive_non_transitivity(). | |
1665 | * Returns WIN if str1, str2 and str3 can be disconnected. | |
1666 | */ | |
1667 | ||
1668 | int | |
1669 | non_transitivity(int str1, int str2, int str3, int *move) | |
1670 | { | |
1671 | int i, res = WIN, Moves[MAX_MOVES]; | |
1672 | ||
1673 | nodes_connect = 0; | |
1674 | *move = PASS_MOVE; | |
1675 | moves_to_prevent_connection_in_three_moves(Moves, str1, str3); | |
1676 | if (Moves[0] > 0) | |
1677 | res = 0; | |
1678 | order_connection_moves(Moves, str1, str2, OTHER_COLOR(board[str1]), | |
1679 | "non_transitivity"); | |
1680 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) | |
1681 | if (trymove(Moves[i], OTHER_COLOR(board[str1]), | |
1682 | "non_transitivity", str1)) { | |
1683 | if (!recursive_transitivity(str1, str2, str3, move)) { | |
1684 | *move = Moves[i]; | |
1685 | res = WIN; | |
1686 | } | |
1687 | popgo(); | |
1688 | } | |
1689 | return res; | |
1690 | } | |
1691 | ||
1692 | /* Returns WIN if str1, str2 and str3 can be disconnected. */ | |
1693 | ||
1694 | static int | |
1695 | recursive_non_transitivity(int str1, int str2, int str3, int *move) | |
1696 | { | |
1697 | int i, res = WIN, Moves[MAX_MOVES]; | |
1698 | ||
1699 | SETUP_TRACE_INFO2("recursive_non_transitivity", str1, str3); | |
1700 | ||
1701 | if (board[str1] == EMPTY || board[str2] == EMPTY | |
1702 | || board[str3] == EMPTY) { | |
1703 | SGFTRACE2(PASS_MOVE, WIN, "one string already captured"); | |
1704 | return WIN; | |
1705 | } | |
1706 | ||
1707 | if (quiescence_capture(str1, move)) { | |
1708 | SGFTRACE2(*move, WIN, "first string capturable"); | |
1709 | return WIN; | |
1710 | } | |
1711 | if (quiescence_capture(str2, move)) { | |
1712 | SGFTRACE2(*move, WIN, "second string capturable"); | |
1713 | return WIN; | |
1714 | } | |
1715 | if (quiescence_capture(str3, move)) { | |
1716 | SGFTRACE2(*move, WIN, "third string capturable"); | |
1717 | return WIN; | |
1718 | } | |
1719 | ||
1720 | if (same_string(str1, str2) && same_string(str1, str3)) { | |
1721 | SGFTRACE2(PASS_MOVE, 0, "already connected"); | |
1722 | return 0; | |
1723 | } | |
1724 | ||
1725 | if (nodes_connect > connection_node_limit) { | |
1726 | SGFTRACE2(PASS_MOVE, WIN, "connection node limit reached"); | |
1727 | return WIN; | |
1728 | } | |
1729 | ||
1730 | if (stackp == connect_depth) { | |
1731 | SGFTRACE2(PASS_MOVE, WIN, "connection depth limit reached"); | |
1732 | return WIN; | |
1733 | } | |
1734 | ||
1735 | nodes_connect++; | |
1736 | global_connection_node_counter++; | |
1737 | ||
1738 | /* We are at an and node. Only look at forced moves. */ | |
1739 | Moves[0] = 0; | |
1740 | if (prevent_connection_one_move(Moves, str1, str3)) | |
1741 | res = 0; | |
1742 | else if (prevent_connection_two_moves(Moves, str1, str3)) | |
1743 | res = 0; | |
1744 | else if (prevent_simple_connection_three_moves(Moves, str1, str3)) | |
1745 | res = 0; | |
1746 | ||
1747 | if (res == 0) | |
1748 | order_connection_moves(Moves, str1, str2, OTHER_COLOR(board[str1]), | |
1749 | "recursive_non_transitivity"); | |
1750 | for (i = 1; ((i < Moves[0] + 1) && (res == 0)); i++) | |
1751 | if (trymove(Moves[i], OTHER_COLOR(board[str1]), | |
1752 | "recursive_non_transitivity", str1)) { | |
1753 | if (!recursive_transitivity(str1, str2, str3, move)) { | |
1754 | *move = Moves[i]; | |
1755 | res = WIN; | |
1756 | } | |
1757 | popgo(); | |
1758 | } | |
1759 | ||
1760 | if (res == WIN) { | |
1761 | SGFTRACE2(*move, WIN, "success"); | |
1762 | } | |
1763 | else { | |
1764 | SGFTRACE2(PASS_MOVE, 0, "failure"); | |
1765 | } | |
1766 | ||
1767 | return res; | |
1768 | } | |
1769 | ||
1770 | ||
1771 | /* Order the moves so that we try the ones likely to succeed early. */ | |
1772 | static void | |
1773 | order_connection_moves(int *moves, int str1, int str2, int color_to_move, | |
1774 | const char *funcname) | |
1775 | { | |
1776 | int scores[MAX_MOVES]; | |
1777 | int r; | |
1778 | int i, j; | |
1779 | UNUSED(str2); | |
1780 | UNUSED(color_to_move); | |
1781 | ||
1782 | for (r = 1; r <= moves[0]; r++) { | |
1783 | int move = moves[r]; | |
1784 | ||
1785 | /* Look at the neighbors of this move and count the things we | |
1786 | * find. Friendly and opponent stones are related to color, i.e. | |
1787 | * the player to move, not to the color of the string. | |
1788 | * | |
1789 | * We don't use all these values. They are only here so we can | |
1790 | * reuse incremental_order_moves() which was developed for the | |
1791 | * tactical reading. | |
1792 | */ | |
1793 | int number_edges = 0; /* outside board */ | |
1794 | int number_same_string = 0; /* the string being attacked */ | |
1795 | int number_own = 0; /* friendly stone */ | |
1796 | int number_opponent = 0; /* opponent stone */ | |
1797 | int captured_stones = 0; /* number of stones captured by this move */ | |
1798 | int threatened_stones = 0; /* number of stones threatened by this move */ | |
1799 | int saved_stones = 0; /* number of stones in atari saved */ | |
1800 | int number_open = 0; /* empty intersection */ | |
1801 | int libs; | |
1802 | ||
1803 | /* We let the incremental board code do the heavy work. */ | |
1804 | incremental_order_moves(move, color_to_move, str1, &number_edges, | |
1805 | &number_same_string, &number_own, | |
1806 | &number_opponent, &captured_stones, | |
1807 | &threatened_stones, &saved_stones, &number_open); | |
1808 | ||
1809 | if (0) | |
1810 | gprintf("%o %1m values: %d %d %d %d %d %d %d %d\n", move, number_edges, | |
1811 | number_same_string, number_own, number_opponent, | |
1812 | captured_stones, threatened_stones, saved_stones, number_open); | |
1813 | ||
1814 | scores[r] = 0; | |
1815 | libs = approxlib(move, color_to_move, 10, NULL); | |
1816 | ||
1817 | /* Avoid self atari. */ | |
1818 | if (libs == 1 && captured_stones == 0) | |
1819 | scores[r] -= 10; | |
1820 | ||
1821 | /* Good to get many liberties. */ | |
1822 | if (libs < 4) | |
1823 | scores[r] += libs; | |
1824 | else | |
1825 | scores[r] += 4; | |
1826 | ||
1827 | /* Very good to capture opponent stones. */ | |
1828 | if (captured_stones > 0) | |
1829 | scores[r] += 5 + captured_stones; | |
1830 | ||
1831 | /* Good to threaten opponent stones. */ | |
1832 | if (threatened_stones > 0) | |
1833 | scores[r] += 3; | |
1834 | ||
1835 | /* Extremely good to save own stones. */ | |
1836 | if (saved_stones > 0) | |
1837 | scores[r] += 10 + saved_stones; | |
1838 | } | |
1839 | ||
1840 | /* Now sort the moves. We use selection sort since this array will | |
1841 | * probably never be more than 10 moves long. In this case, the | |
1842 | * overhead imposed by quicksort will probably overshadow the gains | |
1843 | * given by the O(n*log(n)) behaviour over the O(n^2) behaviour of | |
1844 | * selection sort. | |
1845 | */ | |
1846 | for (i = 1; i <= moves[0]; i++) { | |
1847 | /* Find the move with the biggest score. */ | |
1848 | int maxscore = scores[i]; | |
1849 | int max_at = i; | |
1850 | for (j = i+1; j <= moves[0]; j++) { | |
1851 | if (scores[j] > maxscore) { | |
1852 | maxscore = scores[j]; | |
1853 | max_at = j; | |
1854 | } | |
1855 | } | |
1856 | ||
1857 | /* Now exchange the move at i with the move at max_at. | |
1858 | * Don't forget to exchange the scores as well. | |
1859 | */ | |
1860 | if (max_at != i) { | |
1861 | int temp = moves[i]; | |
1862 | int tempmax = scores[i]; | |
1863 | ||
1864 | moves[i] = moves[max_at]; | |
1865 | scores[i] = scores[max_at]; | |
1866 | ||
1867 | moves[max_at] = temp; | |
1868 | scores[max_at] = tempmax; | |
1869 | } | |
1870 | } | |
1871 | ||
1872 | if (0) { | |
1873 | gprintf("%oVariation %d:\n", count_variations); | |
1874 | for (i = 1; i <= moves[0]; i++) | |
1875 | gprintf("%o %1M %d\n", moves[i], scores[i]); | |
1876 | } | |
1877 | ||
1878 | if (sgf_dumptree) { | |
1879 | char buf[500]; | |
1880 | char *pos; | |
1881 | int chars; | |
1882 | sprintf(buf, "Move order for %s: %n", funcname, &chars); | |
1883 | pos = buf + chars; | |
1884 | for (i = 1; i <= moves[0]; i++) { | |
1885 | sprintf(pos, "%c%d (%d) %n", J(moves[i]) + 'A' + (J(moves[i]) >= 8), | |
1886 | board_size - I(moves[i]), scores[i], &chars); | |
1887 | pos += chars; | |
1888 | } | |
1889 | sgftreeAddComment(sgf_dumptree, buf); | |
1890 | } | |
1891 | } | |
1892 | ||
1893 | /* Clear statistics. */ | |
1894 | void | |
1895 | reset_connection_node_counter() | |
1896 | { | |
1897 | global_connection_node_counter = 0; | |
1898 | } | |
1899 | ||
1900 | ||
1901 | /* Retrieve statistics. */ | |
1902 | int | |
1903 | get_connection_node_counter() | |
1904 | { | |
1905 | return global_connection_node_counter; | |
1906 | } | |
1907 | ||
1908 | ||
1909 | /********************************************************* | |
1910 | * | |
1911 | * Alternate connection reading algorithm. | |
1912 | * | |
1913 | * This code is enabled with the --enable-alternate-connections | |
1914 | * configure flag at build time or toggled with the | |
1915 | * --alternate-connections option at run time. | |
1916 | * | |
1917 | *********************************************************/ | |
1918 | ||
1919 | /* This has been copied from reading.c and modified. | |
1920 | */ | |
1921 | ||
1922 | #define ADD_CANDIDATE_MOVE(move, distance, moves, distances, num_moves)\ | |
1923 | do {\ | |
1924 | int l;\ | |
1925 | for (l = 0; l < num_moves; l++)\ | |
1926 | if (moves[l] == (move)) {\ | |
1927 | if (distances[l] > distance)\ | |
1928 | distances[l] = distance;\ | |
1929 | break;\ | |
1930 | }\ | |
1931 | if ((l == num_moves) && (num_moves < MAX_MOVES)) {\ | |
1932 | moves[num_moves] = move;\ | |
1933 | distances[num_moves] = distance;\ | |
1934 | (num_moves)++;\ | |
1935 | }\ | |
1936 | } while (0) | |
1937 | ||
1938 | ||
1939 | static int find_string_connection_moves(int str1, int str2, int color_to_move, | |
1940 | int moves[MAX_MOVES], | |
1941 | int *total_distance); | |
1942 | static void clear_connection_data(struct connection_data *conn); | |
1943 | static int trivial_connection(int str1, int str2, int *move); | |
1944 | static int does_secure_through_ladder(int color, int move, int pos); | |
1945 | static int ladder_capture(int str, int *move); | |
1946 | static int ladder_capturable(int pos, int color); | |
1947 | static int no_escape_from_atari(int str); | |
1948 | static int no_escape_from_ladder(int str); | |
1949 | static int check_self_atari(int pos, int color_to_move); | |
1950 | static int common_vulnerabilities(int a1, int a2, int b1, int b2, int color); | |
1951 | static int common_vulnerability(int apos, int bpos, int color); | |
1952 | ||
1953 | /* Try to connect two strings. This function is called in a mutual | |
1954 | * recursion with recursive_disconnect2(). Return codes is identical to | |
1955 | * the tactical reading functions. For the has_passed parameter, see the | |
1956 | * documentation of recursive_disconnect2(). | |
1957 | * | |
1958 | * The algorithm is | |
1959 | * 1. Check if the strings are trivially connected or disconnected or | |
1960 | * the result is already cached. | |
1961 | * 2. Find connection moves. | |
1962 | * 3. Try one move at a time and call recursive_disconnect2() to see | |
1963 | * whether we were successful. | |
1964 | * 4. If no move was found we assume success if the connection | |
1965 | * distance was small and failure otherwise. | |
1966 | */ | |
1967 | static int | |
1968 | recursive_connect2(int str1, int str2, int *move, int has_passed) | |
1969 | { | |
1970 | int color = board[str1]; | |
1971 | int moves[MAX_MOVES]; | |
1972 | int num_moves; | |
1973 | int distance = FP(0.0); | |
1974 | int k; | |
1975 | int xpos; | |
1976 | int savemove = NO_MOVE; | |
1977 | int savecode = 0; | |
1978 | int tried_moves = 0; | |
1979 | int value; | |
1980 | ||
1981 | SETUP_TRACE_INFO2("recursive_connect2", str1, str2); | |
1982 | ||
1983 | if (move) | |
1984 | *move = NO_MOVE; | |
1985 | ||
1986 | nodes_connect++; | |
1987 | global_connection_node_counter++; | |
1988 | ||
1989 | if (board[str1] == EMPTY || board[str2] == EMPTY) { | |
1990 | SGFTRACE2(PASS_MOVE, 0, "one string already captured"); | |
1991 | return 0; | |
1992 | } | |
1993 | ||
1994 | if (same_string(str1, str2)) { | |
1995 | SGFTRACE2(PASS_MOVE, WIN, "already connected"); | |
1996 | return WIN; | |
1997 | } | |
1998 | ||
1999 | if (nodes_connect > connection_node_limit) { | |
2000 | SGFTRACE2(PASS_MOVE, 0, "connection node limit reached"); | |
2001 | return 0; | |
2002 | } | |
2003 | ||
2004 | if (stackp > connect_depth2) { | |
2005 | SGFTRACE2(PASS_MOVE, 0, "connection depth limit reached"); | |
2006 | return 0; | |
2007 | } | |
2008 | ||
2009 | str1 = find_origin(str1); | |
2010 | str2 = find_origin(str2); | |
2011 | ||
2012 | if (stackp <= depth && !has_passed | |
2013 | && tt_get(&ttable, CONNECT, str1, str2, depth - stackp, NULL, | |
2014 | &value, NULL, &xpos) == 2) { | |
2015 | TRACE_CACHED_RESULT2(value, value, xpos); | |
2016 | if (value != 0) | |
2017 | if (move) | |
2018 | *move = xpos; | |
2019 | ||
2020 | SGFTRACE2(xpos, value, "cached"); | |
2021 | return value; | |
2022 | } | |
2023 | ||
2024 | if (trivial_connection(str1, str2, &xpos) == WIN) { | |
2025 | SGFTRACE2(xpos, WIN, "trivial connection"); | |
2026 | READ_RETURN_CONN(CONNECT, str1, str2, depth - stackp, move, xpos, WIN); | |
2027 | } | |
2028 | ||
2029 | num_moves = find_string_connection_moves(str1, str2, color, | |
2030 | moves, &distance); | |
2031 | ||
2032 | for (k = 0; k < num_moves; k++) { | |
2033 | int ko_move; | |
2034 | xpos = moves[k]; | |
2035 | ||
2036 | if (komaster_trymove(xpos, color, "recursive_connect2", str1, | |
2037 | &ko_move, stackp <= ko_depth && savecode == 0)) { | |
2038 | tried_moves++; | |
2039 | if (!ko_move) { | |
2040 | int acode = recursive_disconnect2(str1, str2, NULL, | |
2041 | ||
2042 | has_passed); | |
2043 | popgo(); | |
2044 | if (acode == 0) { | |
2045 | SGFTRACE2(xpos, WIN, "connection effective"); | |
2046 | READ_RETURN_CONN(CONNECT, str1, str2, depth - stackp, | |
2047 | move, xpos, WIN); | |
2048 | } | |
2049 | /* if the move works with ko we save it, then look for something | |
2050 | * better. | |
2051 | */ | |
2052 | UPDATE_SAVED_KO_RESULT(savecode, savemove, acode, xpos); | |
2053 | } | |
2054 | else { | |
2055 | if (recursive_disconnect2(str1, str2, NULL, | |
2056 | ||
2057 | has_passed) != WIN) { | |
2058 | savemove = xpos; | |
2059 | savecode = KO_B; | |
2060 | } | |
2061 | popgo(); | |
2062 | } | |
2063 | } | |
2064 | } | |
2065 | ||
2066 | if (tried_moves == 0 && distance < FP(1.0)) { | |
2067 | SGFTRACE2(NO_MOVE, WIN, "no move, probably connected"); | |
2068 | READ_RETURN_CONN(CONNECT, str1, str2, depth - stackp, move, NO_MOVE, WIN); | |
2069 | } | |
2070 | ||
2071 | if (savecode != 0) { | |
2072 | SGFTRACE2(savemove, savecode, "saved move"); | |
2073 | READ_RETURN_CONN(CONNECT, str1, str2, depth - stackp, | |
2074 | move, savemove, savecode); | |
2075 | } | |
2076 | ||
2077 | SGFTRACE2(0, 0, NULL); | |
2078 | READ_RETURN_CONN(CONNECT, str1, str2, depth - stackp, move, NO_MOVE, 0); | |
2079 | } | |
2080 | ||
2081 | ||
2082 | /* Try to disconnect two strings. This function is called in a mutual | |
2083 | * recursion with recursive_connect2(). Return codes is identical to | |
2084 | * the tactical reading functions. | |
2085 | * | |
2086 | * The algorithm is | |
2087 | * 1. Check if the strings are trivially connected or disconnected or | |
2088 | * the result is already cached. | |
2089 | * 2. Find disconnection moves. | |
2090 | * 3. Try one move at a time and call recursive_connect2() to see | |
2091 | * whether we were successful. | |
2092 | * 4. If no move was found we assume failure if the connection | |
2093 | * distance was small. Otherwise we pass and let | |
2094 | * recursive_connect2() try to connect. However, if we already have | |
2095 | * passed once we just declare success. Whether a pass already has | |
2096 | * been made is indicated by the has_passed parameter. | |
2097 | */ | |
2098 | static int | |
2099 | recursive_disconnect2(int str1, int str2, int *move, int has_passed) | |
2100 | { | |
2101 | int color = board[str1]; | |
2102 | int other = OTHER_COLOR(color); | |
2103 | int moves[MAX_MOVES]; | |
2104 | int num_moves; | |
2105 | int distance = FP(0.0); | |
2106 | int k; | |
2107 | int xpos; | |
2108 | int savemove = NO_MOVE; | |
2109 | int savecode = 0; | |
2110 | int tried_moves = 0; | |
2111 | int attack_code1; | |
2112 | int attack_pos1; | |
2113 | int attack_code2; | |
2114 | int attack_pos2; | |
2115 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
2116 | int save_count_variations = count_variations; | |
2117 | int value; | |
2118 | ||
2119 | SETUP_TRACE_INFO2("recursive_disconnect2", str1, str2); | |
2120 | ||
2121 | nodes_connect++; | |
2122 | global_connection_node_counter++; | |
2123 | ||
2124 | if (move) | |
2125 | *move = NO_MOVE; | |
2126 | ||
2127 | if (board[str1] == EMPTY || board[str2] == EMPTY) { | |
2128 | SGFTRACE2(PASS_MOVE, WIN, "one string already captured"); | |
2129 | return WIN; | |
2130 | } | |
2131 | ||
2132 | if (same_string(str1, str2)) { | |
2133 | SGFTRACE2(PASS_MOVE, 0, "already connected"); | |
2134 | return 0; | |
2135 | } | |
2136 | ||
2137 | if (nodes_connect > connection_node_limit) { | |
2138 | SGFTRACE2(PASS_MOVE, WIN, "connection node limit reached"); | |
2139 | return WIN; | |
2140 | } | |
2141 | ||
2142 | if (stackp > connect_depth2) { | |
2143 | SGFTRACE2(PASS_MOVE, WIN, "connection depth limit reached"); | |
2144 | return WIN; | |
2145 | } | |
2146 | ||
2147 | sgf_dumptree = NULL; | |
2148 | count_variations = 0; | |
2149 | ||
2150 | str1 = find_origin(str1); | |
2151 | str2 = find_origin(str2); | |
2152 | ||
2153 | attack_code1 = attack(str1, &attack_pos1); | |
2154 | if (attack_code1 == WIN) { | |
2155 | sgf_dumptree = save_sgf_dumptree; | |
2156 | count_variations = save_count_variations; | |
2157 | ||
2158 | SGFTRACE2(attack_pos1, WIN, "one string is capturable"); | |
2159 | if (move) | |
2160 | *move = attack_pos1; | |
2161 | ||
2162 | return WIN; | |
2163 | } | |
2164 | ||
2165 | attack_code2 = attack(str2, &attack_pos2); | |
2166 | if (attack_code2 == WIN) { | |
2167 | sgf_dumptree = save_sgf_dumptree; | |
2168 | count_variations = save_count_variations; | |
2169 | ||
2170 | SGFTRACE2(attack_pos2, WIN, "one string is capturable"); | |
2171 | if (move) | |
2172 | *move = attack_pos2; | |
2173 | ||
2174 | return WIN; | |
2175 | } | |
2176 | ||
2177 | sgf_dumptree = save_sgf_dumptree; | |
2178 | count_variations = save_count_variations; | |
2179 | ||
2180 | if (stackp <= depth | |
2181 | && tt_get(&ttable, DISCONNECT, str1, str2, | |
2182 | depth - stackp, NULL, | |
2183 | &value, NULL, &xpos) == 2) { | |
2184 | TRACE_CACHED_RESULT2(value, value, xpos); | |
2185 | if (value != 0) | |
2186 | if (move) | |
2187 | *move = xpos; | |
2188 | ||
2189 | SGFTRACE2(xpos, value, "cached"); | |
2190 | return value; | |
2191 | } | |
2192 | ||
2193 | if (ladder_capture(str1, &xpos) == WIN) { | |
2194 | SGFTRACE2(xpos, WIN, "first string capturable"); | |
2195 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, move, xpos, WIN); | |
2196 | } | |
2197 | ||
2198 | if (ladder_capture(str2, &xpos) == WIN) { | |
2199 | SGFTRACE2(xpos, WIN, "second string capturable"); | |
2200 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, move, xpos, WIN); | |
2201 | } | |
2202 | ||
2203 | num_moves = find_string_connection_moves(str1, str2, other, | |
2204 | moves, &distance); | |
2205 | ||
2206 | if (attack_code1 != 0 && num_moves < MAX_MOVES) { | |
2207 | for (k = 0; k < num_moves; k++) { | |
2208 | if (moves[k] == attack_pos1) | |
2209 | break; | |
2210 | } | |
2211 | ||
2212 | if (k == num_moves) | |
2213 | moves[num_moves++] = attack_pos1; | |
2214 | } | |
2215 | ||
2216 | if (attack_code2 != 0 && num_moves < MAX_MOVES) { | |
2217 | for (k = 0; k < num_moves; k++) { | |
2218 | if (moves[k] == attack_pos2) | |
2219 | break; | |
2220 | } | |
2221 | ||
2222 | if (k == num_moves) | |
2223 | moves[num_moves++] = attack_pos2; | |
2224 | } | |
2225 | ||
2226 | for (k = 0; k < num_moves; k++) { | |
2227 | int ko_move; | |
2228 | xpos = moves[k]; | |
2229 | ||
2230 | if (komaster_trymove(xpos, other, "recursive_disconnect2", str1, | |
2231 | &ko_move, stackp <= ko_depth && savecode == 0)) { | |
2232 | tried_moves++; | |
2233 | if (!ko_move) { | |
2234 | int dcode = recursive_connect2(str1, str2, NULL, | |
2235 | has_passed); | |
2236 | popgo(); | |
2237 | if (dcode == 0) { | |
2238 | SGFTRACE2(xpos, WIN, "disconnection effective"); | |
2239 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, | |
2240 | move, xpos, WIN); | |
2241 | } | |
2242 | /* if the move works with ko we save it, then look for something | |
2243 | * better. | |
2244 | */ | |
2245 | UPDATE_SAVED_KO_RESULT(savecode, savemove, dcode, xpos); | |
2246 | } | |
2247 | else { | |
2248 | if (recursive_connect2(str1, str2, NULL, | |
2249 | ||
2250 | has_passed) != WIN) { | |
2251 | savemove = xpos; | |
2252 | savecode = KO_B; | |
2253 | } | |
2254 | popgo(); | |
2255 | } | |
2256 | } | |
2257 | } | |
2258 | ||
2259 | if (tried_moves == 0 | |
2260 | && distance >= FP(1.0) | |
2261 | && (has_passed | |
2262 | || !recursive_connect2(str1, str2, NULL, 1))) { | |
2263 | SGFTRACE2(NO_MOVE, WIN, "no move, probably disconnected"); | |
2264 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, | |
2265 | move, NO_MOVE, WIN); | |
2266 | } | |
2267 | ||
2268 | if (savecode != 0) { | |
2269 | SGFTRACE2(savemove, savecode, "saved move"); | |
2270 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, | |
2271 | move, savemove, savecode); | |
2272 | } | |
2273 | ||
2274 | SGFTRACE2(0, 0, NULL); | |
2275 | READ_RETURN_CONN(DISCONNECT, str1, str2, depth - stackp, move, NO_MOVE, 0); | |
2276 | } | |
2277 | ||
2278 | ||
2279 | /* Find moves to connect or disconnect the two strings str1 and str2. | |
2280 | * If color_to_move equals the color of the strings we search for | |
2281 | * connecting moves and otherwise disconnecting moves. The moves are | |
2282 | * returned in the moves[] array and the number of moves is the return | |
2283 | * value of the function. The parameter *total_distance is set to the | |
2284 | * approximated connection distance between the two strings. This is | |
2285 | * most useful when no moves are found. If *total_distance is small | |
2286 | * they are probably already effectively connected and if it is huge | |
2287 | * they are probably disconnected. | |
2288 | * | |
2289 | * The algorithm is to compute connection distances around each string | |
2290 | * and find points where the sum of the distances is small, or more | |
2291 | * exactly where the sum of the distances after the move would be | |
2292 | * small. This can be done with help of delta values returned together | |
2293 | * with distance values from the function | |
2294 | * compute_connection_distances(). This "distance after move" measure | |
2295 | * is modified with various bonuses and then used to order the found | |
2296 | * moves. | |
2297 | */ | |
2298 | static int | |
2299 | find_connection_moves(int str1, int str2, int color_to_move, | |
2300 | struct connection_data *conn1, | |
2301 | struct connection_data *conn2, | |
2302 | int max_dist1, int max_dist2, | |
2303 | int moves[MAX_MOVES], int total_distance, | |
2304 | int cutoff) | |
2305 | { | |
2306 | int color = board[str1]; | |
2307 | int other = OTHER_COLOR(color); | |
2308 | int connect_move = (color_to_move == color); | |
2309 | int r; | |
2310 | int distances[MAX_MOVES]; | |
2311 | int num_moves = 0; | |
2312 | int acode = 0; | |
2313 | int attack_move = NO_MOVE; | |
2314 | int dcode = 0; | |
2315 | int defense_move = NO_MOVE; | |
2316 | int k; | |
2317 | int i, j; | |
2318 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
2319 | int save_count_variations = count_variations; | |
2320 | int distance_limit; | |
2321 | ||
2322 | /* We turn off the sgf traces here to avoid cluttering them up with | |
2323 | * tactical reading moves. | |
2324 | */ | |
2325 | sgf_dumptree = NULL; | |
2326 | count_variations = 0; | |
2327 | ||
2328 | /* Loop through the points with smallish distance from str1 and look | |
2329 | * for ones also having a small distance to str2. | |
2330 | */ | |
2331 | for (r = 0; r < conn1->queue_end; r++) { | |
2332 | int pos = conn1->queue[r]; | |
2333 | int dist1 = conn1->distances[pos]; | |
2334 | int deltadist1 = conn1->deltas[pos]; | |
2335 | int dist2 = conn2->distances[pos]; | |
2336 | int deltadist2 = conn2->deltas[pos]; | |
2337 | int d1; | |
2338 | int d2; | |
2339 | int distance; | |
2340 | ||
2341 | if (dist1 - deltadist1 + dist2 - deltadist2 > FP(2.5) | |
2342 | || dist1 > max_dist1 + FP(0.2) | |
2343 | || dist2 > max_dist2 + FP(0.2)) | |
2344 | continue; | |
2345 | ||
2346 | if (verbose > 0) | |
2347 | gprintf("%oMove %1m, (%f, %f, %f, %f)\n", pos, | |
2348 | FIXED_TO_FLOAT(dist1), FIXED_TO_FLOAT(deltadist1), | |
2349 | FIXED_TO_FLOAT(dist2), FIXED_TO_FLOAT(deltadist2)); | |
2350 | ||
2351 | /* The basic quality of the move is the sum of the distances to | |
2352 | * each string minus the two delta values. This distance value | |
2353 | * will subsequently be modified to take other factors into | |
2354 | * account. | |
2355 | */ | |
2356 | d1 = dist1 - deltadist1; | |
2357 | d2 = dist2 - deltadist2; | |
2358 | distance = d1 + d2; | |
2359 | if (verbose > 0) | |
2360 | gprintf("%o %f, primary distance\n", FIXED_TO_FLOAT(distance)); | |
2361 | ||
2362 | /* Bonus if d1 and d2 are well balanced. */ | |
2363 | if ((3 * d1) / 2 > d2 && (3 * d2) / 2 > d1) { | |
2364 | distance -= FP(0.1); | |
2365 | if (verbose > 0) | |
2366 | gprintf("%o -0.1, well balanced\n"); | |
2367 | } | |
2368 | ||
2369 | /* Check whether the move is "between" the two strings. */ | |
2370 | if (conn1->coming_from[pos] != NO_MOVE | |
2371 | && conn1->coming_from[pos] == conn2->coming_from[pos]) { | |
2372 | if (verbose > 0) | |
2373 | gprintf("%o discarded, not between strings\n"); | |
2374 | continue; | |
2375 | } | |
2376 | ||
2377 | if (board[pos] == EMPTY) { | |
2378 | if (check_self_atari(pos, color_to_move)) { | |
2379 | ADD_CANDIDATE_MOVE(pos, distance, moves, distances, num_moves); | |
2380 | } | |
2381 | else { | |
2382 | if (verbose > 0) | |
2383 | gprintf("%o discarded, self atari\n"); | |
2384 | } | |
2385 | } | |
2386 | else if (board[pos] == other) { | |
2387 | attack_and_defend(pos, &acode, &attack_move, &dcode, &defense_move); | |
2388 | if (verbose > 0) | |
2389 | gprintf("%o attack with code %d at %1m, defense with code %d at %1m\n", | |
2390 | acode, attack_move, dcode, defense_move); | |
2391 | ||
2392 | if (connect_move && acode != 0) { | |
2393 | if (dcode == 0) { | |
2394 | distance += FP(0.5); | |
2395 | if (verbose > 0) | |
2396 | gprintf("%o +0.5, no defense\n"); | |
2397 | } | |
2398 | else { | |
2399 | if (conn1->distances[attack_move] | |
2400 | + conn2->distances[attack_move] > dist1 + dist2) { | |
2401 | distance += FP(0.5); | |
2402 | if (verbose > 0) | |
2403 | gprintf("%o +0.5, attack point not on shortest path\n"); | |
2404 | } | |
2405 | } | |
2406 | ADD_CANDIDATE_MOVE(attack_move, distance - FP(0.15), moves, distances, | |
2407 | num_moves); | |
2408 | if (verbose > 0) | |
2409 | gprintf("%o -0.15 at %1m, capturing a string\n", attack_move); | |
2410 | } | |
2411 | else if (!connect_move && acode != 0 && dcode != 0) { | |
2412 | ADD_CANDIDATE_MOVE(defense_move, distance - FP(0.5), moves, distances, | |
2413 | num_moves); | |
2414 | if (verbose > 0) | |
2415 | gprintf("%o -0.5 at %1m, defending a string\n", defense_move); | |
2416 | } | |
2417 | } | |
2418 | else if (board[pos] == color) { | |
2419 | /* Check whether there are common vulnerable points. */ | |
2420 | for (k = 0; k < 4; k++) { | |
2421 | int apos, bpos; | |
2422 | if (k & 1) | |
2423 | apos = conn1->vulnerable1[pos]; | |
2424 | else | |
2425 | apos = conn1->vulnerable2[pos]; | |
2426 | ||
2427 | if (k & 2) | |
2428 | bpos = conn2->vulnerable1[pos]; | |
2429 | else | |
2430 | bpos = conn2->vulnerable2[pos]; | |
2431 | ||
2432 | if (common_vulnerability(apos, bpos, color)) { | |
2433 | if (check_self_atari(apos, color_to_move)) { | |
2434 | ADD_CANDIDATE_MOVE(apos, distance, moves, distances, num_moves); | |
2435 | if (verbose > 0) | |
2436 | gprintf("%o +0.0 at %1m, vulnerability\n", apos); | |
2437 | } | |
2438 | ||
2439 | if (bpos != apos | |
2440 | && check_self_atari(bpos, color_to_move)) { | |
2441 | ADD_CANDIDATE_MOVE(bpos, distance, moves, distances, num_moves); | |
2442 | if (verbose > 0) | |
2443 | gprintf("%o +0.0 at %1m, vulnerability\n", bpos); | |
2444 | } | |
2445 | } | |
2446 | } | |
2447 | } | |
2448 | } | |
2449 | ||
2450 | /* Modify the distance values for the moves with various bonuses. */ | |
2451 | for (r = 0; r < num_moves; r++) { | |
2452 | int move = moves[r]; | |
2453 | int adjacent_to_attacker = 0; | |
2454 | int bonus_given = 0; | |
2455 | ||
2456 | for (k = 0; k < 4; k++) { | |
2457 | int pos = move + delta[k]; | |
2458 | if (board[pos] == other) { | |
2459 | adjacent_to_attacker = 1; | |
2460 | distances[r] -= FP(0.15); | |
2461 | if (verbose > 0) | |
2462 | gprintf("%o%1M -0.15, adjacent to attacker string\n", move); | |
2463 | if (countlib(pos) <= 2) { | |
2464 | distances[r] -= FP(0.2); | |
2465 | if (verbose > 0) | |
2466 | gprintf("%o%1M -0.2, adjacent to attacker string with at most two liberties\n", move); | |
2467 | if ((connect_move || !bonus_given) | |
2468 | && (conn1->distances[move] - conn1->deltas[move] <= FP(0.5) | |
2469 | || conn1->distances[pos] - conn1->deltas[pos] <= FP(0.5)) | |
2470 | && (conn2->distances[move] - conn2->deltas[move] <= FP(0.5) | |
2471 | || conn2->distances[pos] - conn2->deltas[pos] <= FP(0.5)) | |
2472 | && conn1->distances[pos] < total_distance | |
2473 | && conn2->distances[pos] < total_distance) { | |
2474 | bonus_given = 1; | |
2475 | distances[r] -= FP(0.7); | |
2476 | if (verbose > 0) | |
2477 | gprintf("%o%1M -0.7, capture or atari of immediately connecting string\n", move); | |
2478 | } | |
2479 | } | |
2480 | } | |
2481 | else if (board[pos] == color) { | |
2482 | if (countlib(pos) <= 2) { | |
2483 | distances[r] -= FP(0.2); | |
2484 | if (verbose > 0) | |
2485 | gprintf("%o%1M -0.2, adjacent to defender string with at most two liberties\n", move); | |
2486 | } | |
2487 | /* The code above (in the 'board[pos] == other' branch) makes | |
2488 | * perfect sense for the defender, but has a tendency to | |
2489 | * overestimate solid connection defenses when the attacker's | |
2490 | * stones happen to be in atari, specially when capturing some | |
2491 | * defender stones instead would help just as well, if not better. | |
2492 | * The following code compensates in such kind of situations. | |
2493 | * See connection:111 and gunnar:53 for example. | |
2494 | */ | |
2495 | if (!connect_move && countlib(pos) == 1 | |
2496 | /* let's avoid ko and snapbacks */ | |
2497 | && accuratelib(move, other, 2, NULL) > 1) { | |
2498 | int adjs[MAXCHAIN]; | |
2499 | int bonus; | |
2500 | bonus = FP(0.1) * chainlinks2(pos, adjs, 2); | |
2501 | bonus += FP(0.5) * chainlinks2(pos, adjs, 1); | |
2502 | distances[r] -= bonus; | |
2503 | if (verbose > 0) | |
2504 | gprintf("%o%1M -%f, capture of defender string\n", | |
2505 | move, FIXED_TO_FLOAT(bonus)); | |
2506 | } | |
2507 | } | |
2508 | } | |
2509 | if (adjacent_to_attacker | |
2510 | && !connect_move | |
2511 | && is_edge_vertex(move)) { | |
2512 | distances[r] -= FP(0.1); | |
2513 | if (verbose > 0) | |
2514 | gprintf("%o%1M -0.1, disconnect move on edge\n", move); | |
2515 | } | |
2516 | ||
2517 | if (ladder_capturable(move, color_to_move)) { | |
2518 | distances[r] += FP(0.3); | |
2519 | if (verbose > 0) | |
2520 | gprintf("%o%1M +0.3, can be captured in a ladder\n", move); | |
2521 | } | |
2522 | ||
2523 | /* Bonus for moves adjacent to endpoint strings with 3 liberties. | |
2524 | * Neighbor strings with less than 3 liberties have already | |
2525 | * generated a bonus above. | |
2526 | */ | |
2527 | if ((liberty_of_string(move, str1) | |
2528 | && countlib(str1) == 3) | |
2529 | || (ON_BOARD(str2) && liberty_of_string(move, str2) | |
2530 | && countlib(str2) == 3)) { | |
2531 | distances[r] -= FP(0.1); | |
2532 | if (verbose > 0) | |
2533 | gprintf("%o%1M -0.1, liberty of endpoint string with 3 libs\n", move); | |
2534 | } | |
2535 | } | |
2536 | ||
2537 | /* Turn the sgf traces back on. */ | |
2538 | sgf_dumptree = save_sgf_dumptree; | |
2539 | count_variations = save_count_variations; | |
2540 | ||
2541 | /* Now sort the moves. We use selection sort since this array will | |
2542 | * probably never be more than 10 moves long. In this case, the | |
2543 | * overhead imposed by quicksort will probably overshadow the gains | |
2544 | * given by the O(n*log(n)) behaviour over the O(n^2) behaviour of | |
2545 | * selection sort. | |
2546 | */ | |
2547 | for (i = 0; i < num_moves; i++) { | |
2548 | /* Find the move with the smallest distance. */ | |
2549 | int mindistance = distances[i]; | |
2550 | int min_at = i; | |
2551 | for (j = i + 1; j < num_moves; j++) { | |
2552 | if (distances[j] < mindistance) { | |
2553 | mindistance = distances[j]; | |
2554 | min_at = j; | |
2555 | } | |
2556 | } | |
2557 | ||
2558 | /* Now exchange the move at i with the move at min_at. | |
2559 | * Don't forget to exchange the distances as well. | |
2560 | */ | |
2561 | if (min_at != i) { | |
2562 | int temp = moves[i]; | |
2563 | int tempmin = distances[i]; | |
2564 | ||
2565 | moves[i] = moves[min_at]; | |
2566 | distances[i] = distances[min_at]; | |
2567 | ||
2568 | moves[min_at] = temp; | |
2569 | distances[min_at] = tempmin; | |
2570 | } | |
2571 | } | |
2572 | ||
2573 | if (verbose > 0) { | |
2574 | gprintf("%oSorted moves:\n"); | |
2575 | for (i = 0; i < num_moves; i++) | |
2576 | gprintf("%o%1M %f\n", moves[i], FIXED_TO_FLOAT(distances[i])); | |
2577 | } | |
2578 | ||
2579 | if (sgf_dumptree) { | |
2580 | char buf[500]; | |
2581 | char *pos; | |
2582 | int chars; | |
2583 | sprintf(buf, "Move order for %sconnect: %n", | |
2584 | connect_move ? "" : "dis", &chars); | |
2585 | pos = buf + chars; | |
2586 | for (i = 0; i < num_moves; i++) { | |
2587 | sprintf(pos, "%c%d (%4.2f) %n", J(moves[i]) + 'A' + (J(moves[i]) >= 8), | |
2588 | board_size - I(moves[i]), FIXED_TO_FLOAT(distances[i]), | |
2589 | &chars); | |
2590 | pos += chars; | |
2591 | } | |
2592 | if (cutoff < HUGE_CONNECTION_DISTANCE) { | |
2593 | sprintf(pos, "(cutoff %f)%n", FIXED_TO_FLOAT(cutoff), &chars); | |
2594 | pos += chars; | |
2595 | } | |
2596 | sgftreeAddComment(sgf_dumptree, buf); | |
2597 | } | |
2598 | ||
2599 | if (num_moves == 0) | |
2600 | return num_moves; | |
2601 | ||
2602 | /* Filter out moves with distance at least 1.5 more than the best | |
2603 | * move, or with distance higher than the cutoff specified. | |
2604 | * | |
2605 | * In order to further reduce the branching factor, a decreasing | |
2606 | * cutoff is applied between candidates. For instance, in this case | |
2607 | * 1. d 2. d+0.5 3. d+1.0 4. d+1.5 | |
2608 | * the 4th candidate will be tested, while in following one | |
2609 | * 1. d 2. d+0.1 3. d+0.2 4. d+1.5 | |
2610 | * it will be discarded. | |
2611 | */ | |
2612 | if (num_moves <= 1 || !is_ko(moves[0], color_to_move, NULL)) | |
2613 | distance_limit = distances[0] + FP(1.5); | |
2614 | else | |
2615 | distance_limit = distances[1] + FP(1.5); | |
2616 | ||
2617 | /* Special case: If the second best move has a distance less than 1, | |
2618 | * include it if even if the best move has a very low distance. | |
2619 | */ | |
2620 | if (num_moves > 1 | |
2621 | && distances[1] < FP(1.0) | |
2622 | && distances[1] > distance_limit) | |
2623 | distance_limit = distances[1]; | |
2624 | ||
2625 | for (r = 0; r < num_moves; r++) { | |
2626 | if (r > 1 | |
2627 | && distances[r] > distances[r-1] | |
2628 | && distances[r] - distances[r-1] > (8 - r) * FP(0.2)) | |
2629 | break; | |
2630 | if (distances[r] > distance_limit | |
2631 | || distances[r] > cutoff) | |
2632 | break; | |
2633 | } | |
2634 | num_moves = r; | |
2635 | ||
2636 | return num_moves; | |
2637 | } | |
2638 | ||
2639 | static int | |
2640 | find_string_connection_moves(int str1, int str2, int color_to_move, | |
2641 | int moves[MAX_MOVES], int *total_distance) | |
2642 | { | |
2643 | struct connection_data conn1; | |
2644 | struct connection_data conn2; | |
2645 | int max_dist1; | |
2646 | int max_dist2; | |
2647 | int num_moves; | |
2648 | int lib; | |
2649 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
2650 | int save_count_variations = count_variations; | |
2651 | ||
2652 | /* We turn off the sgf traces here to avoid cluttering them up with | |
2653 | * tactical reading moves. | |
2654 | */ | |
2655 | sgf_dumptree = NULL; | |
2656 | count_variations = 0; | |
2657 | ||
2658 | compute_connection_distances(str1, str2, FP(3.051), &conn1, 1); | |
2659 | compute_connection_distances(str2, str1, FP(3.051), &conn2, 1); | |
2660 | ||
2661 | if (findlib(str1, 1, &lib) == 1) { | |
2662 | conn1.distances[lib] = 0; | |
2663 | conn1.coming_from[lib] = NO_MOVE; | |
2664 | conn2.distances[lib] = conn2.distances[str1]; | |
2665 | conn2.coming_from[lib] = conn1.coming_from[str1]; | |
2666 | } | |
2667 | ||
2668 | if (findlib(str2, 1, &lib) == 1) { | |
2669 | conn2.distances[lib] = 0; | |
2670 | conn1.distances[lib] = conn1.distances[str2]; | |
2671 | } | |
2672 | ||
2673 | max_dist1 = conn1.distances[str2]; | |
2674 | max_dist2 = conn2.distances[str1]; | |
2675 | ||
2676 | *total_distance = gg_min(max_dist1, max_dist2); | |
2677 | ||
2678 | if (verbose > 0) { | |
2679 | gprintf("%oVariation %d\n", save_count_variations); | |
2680 | dump_stack(); | |
2681 | showboard(0); | |
2682 | print_connection_distances(&conn1); | |
2683 | print_connection_distances(&conn2); | |
2684 | } | |
2685 | ||
2686 | sgf_dumptree = save_sgf_dumptree; | |
2687 | count_variations = save_count_variations; | |
2688 | ||
2689 | num_moves = find_connection_moves(str1, str2, color_to_move, | |
2690 | &conn1, &conn2, max_dist1, max_dist2, | |
2691 | moves, *total_distance, | |
2692 | HUGE_CONNECTION_DISTANCE); | |
2693 | return num_moves; | |
2694 | } | |
2695 | ||
2696 | ||
2697 | static void | |
2698 | add_to_start_queue(int pos, int dist, struct connection_data *conn) | |
2699 | { | |
2700 | conn->queue[conn->queue_end++] = pos; | |
2701 | conn->distances[pos] = dist; | |
2702 | conn->deltas[pos] = dist; | |
2703 | conn->coming_from[pos] = NO_MOVE; | |
2704 | conn->vulnerable1[pos] = NO_MOVE; | |
2705 | conn->vulnerable2[pos] = NO_MOVE; | |
2706 | } | |
2707 | ||
2708 | ||
2709 | void | |
2710 | init_connection_data(int color, const signed char goal[BOARDMAX], | |
2711 | int target, int cutoff, | |
2712 | struct connection_data *conn, int speculative) | |
2713 | { | |
2714 | int pos; | |
2715 | signed char mark[BOARDMAX]; | |
2716 | ||
2717 | memset(mark, 0, BOARDMAX); | |
2718 | VALGRIND_MAKE_WRITABLE(conn, sizeof(conn)); | |
2719 | clear_connection_data(conn); | |
2720 | ||
2721 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
2722 | if (goal[pos]) { | |
2723 | if (board[pos] == color) { | |
2724 | int origin = find_origin(pos); | |
2725 | ||
2726 | if (!mark[origin]) { | |
2727 | add_to_start_queue(origin, FP(0.0), conn); | |
2728 | mark[origin] = 1; | |
2729 | } | |
2730 | } | |
2731 | else if (board[pos] == EMPTY) | |
2732 | add_to_start_queue(pos, FP(1.0), conn); | |
2733 | } | |
2734 | } | |
2735 | ||
2736 | conn->target = target; | |
2737 | conn->cutoff_distance = cutoff; | |
2738 | conn->speculative = speculative; | |
2739 | } | |
2740 | ||
2741 | static int | |
2742 | find_break_moves(int str, const signed char goal[BOARDMAX], int color_to_move, | |
2743 | int moves[MAX_MOVES], int *total_distance) | |
2744 | { | |
2745 | struct connection_data conn1; | |
2746 | struct connection_data conn2; | |
2747 | int max_dist1 = HUGE_CONNECTION_DISTANCE; | |
2748 | int max_dist2; | |
2749 | int num_moves; | |
2750 | int str2 = NO_MOVE; | |
2751 | int color = board[str]; | |
2752 | int lib; | |
2753 | int k; | |
2754 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
2755 | int save_count_variations = count_variations; | |
2756 | ||
2757 | /* We turn off the sgf traces here to avoid cluttering them up with | |
2758 | * tactical reading moves. | |
2759 | */ | |
2760 | sgf_dumptree = NULL; | |
2761 | count_variations = 0; | |
2762 | ||
2763 | compute_connection_distances(str, NO_MOVE, FP(2.501), &conn1, 1); | |
2764 | for (k = 0; k < conn1.queue_end; k++) | |
2765 | if (board[conn1.queue[k]] == color) { | |
2766 | int stones[MAX_BOARD * MAX_BOARD]; | |
2767 | int num_stones = findstones(conn1.queue[k], | |
2768 | MAX_BOARD * MAX_BOARD, stones); | |
2769 | int i; | |
2770 | for (i = 0; i < num_stones; i++) { | |
2771 | if (goal[stones[i]]) { | |
2772 | str2 = find_origin(stones[i]); | |
2773 | TRACE("%oUsing %1m as secondary target.\n", str2); | |
2774 | mark_string(str2, breakin_shadow, 1); | |
2775 | break; | |
2776 | } | |
2777 | } | |
2778 | if (i < num_stones) | |
2779 | break; | |
2780 | } | |
2781 | ||
2782 | /* Add all stones in the goal to the queue. */ | |
2783 | init_connection_data(color, goal, str, FP(2.501), &conn2, 1); | |
2784 | ||
2785 | for (k = 0; k < conn2.queue_end; k++) { | |
2786 | if (max_dist1 > conn1.distances[conn2.queue[k]]) | |
2787 | max_dist1 = conn1.distances[conn2.queue[k]]; | |
2788 | } | |
2789 | ||
2790 | spread_connection_distances(color, &conn2); | |
2791 | ||
2792 | if (findlib(str, 1, &lib) == 1) { | |
2793 | conn1.distances[lib] = 0; | |
2794 | conn1.coming_from[lib] = NO_MOVE; | |
2795 | conn2.distances[lib] = conn2.distances[str]; | |
2796 | conn2.coming_from[lib] = conn1.coming_from[str]; | |
2797 | } | |
2798 | ||
2799 | max_dist2 = conn2.distances[str]; | |
2800 | *total_distance = gg_min(max_dist1, max_dist2); | |
2801 | ||
2802 | /* Turn the sgf traces back on. */ | |
2803 | sgf_dumptree = save_sgf_dumptree; | |
2804 | count_variations = save_count_variations; | |
2805 | ||
2806 | if (verbose > 0) { | |
2807 | gprintf("%oVariation %d\n", save_count_variations); | |
2808 | dump_stack(); | |
2809 | showboard(0); | |
2810 | print_connection_distances(&conn1); | |
2811 | print_connection_distances(&conn2); | |
2812 | } | |
2813 | ||
2814 | { | |
2815 | int cutoff = HUGE_CONNECTION_DISTANCE; | |
2816 | if (breakin_depth - stackp <= 5) | |
2817 | cutoff = FP(1.101) + (breakin_depth - stackp) * FP(0.15); | |
2818 | num_moves = find_connection_moves(str, str2, color_to_move, | |
2819 | &conn1, &conn2, max_dist1, max_dist2, | |
2820 | moves, *total_distance, cutoff); | |
2821 | } | |
2822 | ||
2823 | if (color_to_move != board[str]) { | |
2824 | int move; | |
2825 | if (num_moves < MAX_MOVES | |
2826 | && ON_BOARD(str2) | |
2827 | && ladder_capture(str2, &move)) { | |
2828 | moves[num_moves++] = move; | |
2829 | } | |
2830 | } | |
2831 | ||
2832 | for (k = 0; k < num_moves; k++) | |
2833 | breakin_shadow[moves[k]] = 1; | |
2834 | ||
2835 | return num_moves; | |
2836 | } | |
2837 | ||
2838 | ||
2839 | /* Can (str) connect to goal[] if the other color moves first? */ | |
2840 | static int | |
2841 | recursive_break(int str, const signed char goal[BOARDMAX], int *move, | |
2842 | int has_passed, | |
2843 | Hash_data *goal_hash) | |
2844 | { | |
2845 | int color = board[str]; | |
2846 | int moves[MAX_MOVES]; | |
2847 | int num_moves; | |
2848 | int distance = FP(0.0); | |
2849 | int k; | |
2850 | int xpos; | |
2851 | int savemove = NO_MOVE; | |
2852 | int savecode = 0; | |
2853 | int tried_moves = 0; | |
2854 | int retval; | |
2855 | ||
2856 | SETUP_TRACE_INFO("recursive_break", str); | |
2857 | ||
2858 | if (move) | |
2859 | *move = NO_MOVE; | |
2860 | ||
2861 | nodes_connect++; | |
2862 | global_connection_node_counter++; | |
2863 | ||
2864 | if (board[str] == EMPTY) { | |
2865 | SGFTRACE(PASS_MOVE, 0, "one string already captured"); | |
2866 | return 0; | |
2867 | } | |
2868 | ||
2869 | if (nodes_connect > breakin_node_limit) { | |
2870 | SGFTRACE(PASS_MOVE, 0, "connection node limit reached"); | |
2871 | return 0; | |
2872 | } | |
2873 | ||
2874 | if (stackp > breakin_depth) { | |
2875 | SGFTRACE(PASS_MOVE, 0, "connection depth limit reached"); | |
2876 | return 0; | |
2877 | } | |
2878 | ||
2879 | str = find_origin(str); | |
2880 | if (stackp <= depth && !has_passed | |
2881 | && tt_get(&ttable, BREAK_IN, str, NO_MOVE, depth - stackp, goal_hash, | |
2882 | &retval, NULL, &xpos) == 2) { | |
2883 | /* FIXME: Use move for move ordering if tt_get() returned 1 */ | |
2884 | TRACE_CACHED_RESULT(retval, xpos); | |
2885 | SGFTRACE(xpos, retval, "cached"); | |
2886 | if (move) | |
2887 | *move = xpos; | |
2888 | return retval; | |
2889 | } | |
2890 | ||
2891 | #if 0 | |
2892 | if (trivial_connection(str1, str2, &xpos) == WIN) { | |
2893 | SGFTRACE2(xpos, WIN, "trivial connection"); | |
2894 | READ_RETURN_HASH(BREAK_IN, str, depth - stackp, goal_hash, | |
2895 | move, xpos, WIN); | |
2896 | } | |
2897 | #endif | |
2898 | ||
2899 | num_moves = find_break_moves(str, goal, color, moves, &distance); | |
2900 | ||
2901 | for (k = 0; k < num_moves; k++) { | |
2902 | int ko_move; | |
2903 | xpos = moves[k]; | |
2904 | ||
2905 | if (komaster_trymove(xpos, color, "recursive_break", str, | |
2906 | &ko_move, stackp <= ko_depth && savecode == 0)) { | |
2907 | tried_moves++; | |
2908 | if (!ko_move) { | |
2909 | int acode = recursive_block(str, goal, NULL, has_passed, goal_hash); | |
2910 | popgo(); | |
2911 | if (acode == 0) { | |
2912 | SGFTRACE(xpos, WIN, "break effective"); | |
2913 | READ_RETURN_HASH(BREAK_IN, str, depth - stackp, goal_hash, | |
2914 | move, xpos, WIN); | |
2915 | } | |
2916 | /* if the move works with ko we save it, then look for something | |
2917 | * better. | |
2918 | */ | |
2919 | UPDATE_SAVED_KO_RESULT(savecode, savemove, acode, xpos); | |
2920 | } | |
2921 | else { | |
2922 | if (recursive_block(str, goal, NULL, has_passed, goal_hash) != WIN) { | |
2923 | savemove = xpos; | |
2924 | savecode = KO_B; | |
2925 | } | |
2926 | popgo(); | |
2927 | } | |
2928 | } | |
2929 | } | |
2930 | ||
2931 | /* Because of a couple differences between the break-in and the | |
2932 | * connection reading code, we can't afford to be as optimistic | |
2933 | * as in recursive_connect2() here. See nando:32 | |
2934 | */ | |
2935 | if (tried_moves == 0 && distance < FP(0.89)) { | |
2936 | SGFTRACE(NO_MOVE, WIN, "no move, probably connected"); | |
2937 | READ_RETURN_HASH(BREAK_IN, str, depth - stackp, goal_hash, | |
2938 | move, NO_MOVE, WIN); | |
2939 | } | |
2940 | ||
2941 | if (savecode != 0) { | |
2942 | SGFTRACE(savemove, savecode, "saved move"); | |
2943 | READ_RETURN_HASH(BREAK_IN, str, depth - stackp, goal_hash, | |
2944 | move, savemove, savecode); | |
2945 | } | |
2946 | ||
2947 | SGFTRACE(0, 0, NULL); | |
2948 | READ_RETURN_HASH(BREAK_IN, str, depth - stackp, goal_hash, move, NO_MOVE, 0); | |
2949 | } | |
2950 | ||
2951 | ||
2952 | /* Can (str) connect to goal[] if the other color moves first? */ | |
2953 | static int | |
2954 | recursive_block(int str, const signed char goal[BOARDMAX], int *move, | |
2955 | int has_passed, Hash_data *goal_hash) | |
2956 | { | |
2957 | int color = board[str]; | |
2958 | int other = OTHER_COLOR(color); | |
2959 | int moves[MAX_MOVES]; | |
2960 | int num_moves; | |
2961 | int distance = FP(0.0); | |
2962 | int k; | |
2963 | int xpos; | |
2964 | int savemove = NO_MOVE; | |
2965 | int savecode = 0; | |
2966 | int tried_moves = 0; | |
2967 | int retval; | |
2968 | SETUP_TRACE_INFO("recursive_block", str); | |
2969 | ||
2970 | nodes_connect++; | |
2971 | global_connection_node_counter++; | |
2972 | ||
2973 | if (move) | |
2974 | *move = NO_MOVE; | |
2975 | ||
2976 | if (board[str] == EMPTY) { | |
2977 | SGFTRACE(PASS_MOVE, WIN, "string already captured"); | |
2978 | return WIN; | |
2979 | } | |
2980 | ||
2981 | #if 0 | |
2982 | if (same_string(str1, str2)) { | |
2983 | SGFTRACE(PASS_MOVE, 0, "already connected"); | |
2984 | return 0; | |
2985 | } | |
2986 | #endif | |
2987 | ||
2988 | if (nodes_connect > breakin_node_limit) { | |
2989 | SGFTRACE(PASS_MOVE, WIN, "connection node limit reached"); | |
2990 | return WIN; | |
2991 | } | |
2992 | ||
2993 | if (stackp > breakin_depth) { | |
2994 | SGFTRACE(PASS_MOVE, WIN, "connection depth limit reached"); | |
2995 | return WIN; | |
2996 | } | |
2997 | ||
2998 | str = find_origin(str); | |
2999 | if (stackp <= depth | |
3000 | && tt_get(&ttable, BLOCK_OFF, str, NO_MOVE, | |
3001 | depth - stackp, goal_hash, &retval, NULL, &xpos) == 2) { | |
3002 | TRACE_CACHED_RESULT(retval, xpos); | |
3003 | SGFTRACE(xpos, retval, "cached"); | |
3004 | if (move) | |
3005 | *move = xpos; | |
3006 | return retval; | |
3007 | } | |
3008 | ||
3009 | if (ladder_capture(str, &xpos) == WIN) { | |
3010 | SGFTRACE(xpos, WIN, "string capturable"); | |
3011 | READ_RETURN_HASH(BLOCK_OFF, str, depth - stackp, goal_hash, | |
3012 | move, xpos, WIN); | |
3013 | } | |
3014 | ||
3015 | num_moves = find_break_moves(str, goal, other, moves, &distance); | |
3016 | ||
3017 | for (k = 0; k < num_moves; k++) { | |
3018 | int ko_move; | |
3019 | xpos = moves[k]; | |
3020 | ||
3021 | if (komaster_trymove(xpos, other, "recursive_block", str, | |
3022 | &ko_move, stackp <= ko_depth && savecode == 0)) { | |
3023 | tried_moves++; | |
3024 | if (!ko_move) { | |
3025 | int dcode = recursive_break(str, goal, NULL, has_passed, goal_hash); | |
3026 | popgo(); | |
3027 | if (dcode == 0) { | |
3028 | SGFTRACE(xpos, WIN, "block effective"); | |
3029 | READ_RETURN_HASH(BLOCK_OFF, str, depth - stackp, goal_hash, | |
3030 | move, xpos, WIN); | |
3031 | } | |
3032 | /* if the move works with ko we save it, then look for something | |
3033 | * better. | |
3034 | */ | |
3035 | UPDATE_SAVED_KO_RESULT(savecode, savemove, dcode, xpos); | |
3036 | } | |
3037 | else { | |
3038 | if (recursive_break(str, goal, NULL, | |
3039 | has_passed, goal_hash) != WIN) { | |
3040 | savemove = xpos; | |
3041 | savecode = KO_B; | |
3042 | } | |
3043 | popgo(); | |
3044 | } | |
3045 | } | |
3046 | } | |
3047 | ||
3048 | if (tried_moves == 0 | |
3049 | && distance >= FP(1.0) | |
3050 | && (has_passed | |
3051 | || !recursive_break(str, goal, NULL, 1, | |
3052 | goal_hash))) { | |
3053 | SGFTRACE(NO_MOVE, WIN, "no move, probably disconnected"); | |
3054 | READ_RETURN_HASH(BLOCK_OFF, str, depth - stackp, goal_hash, | |
3055 | move, NO_MOVE, WIN); | |
3056 | } | |
3057 | ||
3058 | if (savecode != 0) { | |
3059 | SGFTRACE(savemove, savecode, "saved move"); | |
3060 | READ_RETURN_HASH(BLOCK_OFF, str, depth - stackp, goal_hash, | |
3061 | move, savemove, savecode); | |
3062 | } | |
3063 | ||
3064 | SGFTRACE(0, 0, NULL); | |
3065 | READ_RETURN_HASH(BLOCK_OFF, str, depth - stackp, goal_hash, | |
3066 | move, NO_MOVE, 0); | |
3067 | } | |
3068 | ||
3069 | ||
3070 | ||
3071 | /* Externally callable frontend to recursive_break. | |
3072 | * Returns WIN if (str) can connect to the area goal[] (which may or may | |
3073 | * not contain stones), if he gets the first move. | |
3074 | */ | |
3075 | int | |
3076 | break_in(int str, const signed char goal[BOARDMAX], int *move) | |
3077 | { | |
3078 | int dummy_move; | |
3079 | int save_verbose; | |
3080 | int result; | |
3081 | int reading_nodes_when_called = get_reading_node_counter(); | |
3082 | double start = 0; | |
3083 | int tactical_nodes; | |
3084 | Hash_data goal_hash = goal_to_hashvalue(goal); | |
3085 | ||
3086 | if (move == NULL) | |
3087 | move = &dummy_move; | |
3088 | ||
3089 | nodes_connect = 0; | |
3090 | *move = PASS_MOVE; | |
3091 | ||
3092 | if (board[str] == EMPTY) | |
3093 | return 0; | |
3094 | str = find_origin(str); | |
3095 | ||
3096 | if (search_persistent_breakin_cache(BREAK_IN, str, &goal_hash, | |
3097 | breakin_node_limit, &result, move)) { | |
3098 | if (debug & DEBUG_BREAKIN) { | |
3099 | gprintf("Break-in from %1m to:\n", str); | |
3100 | goaldump(goal); | |
3101 | gprintf("Result cached: %s %1m\n", result_to_string(result), *move); | |
3102 | } | |
3103 | return result; | |
3104 | } | |
3105 | ||
3106 | save_verbose = verbose; | |
3107 | if (verbose > 0) | |
3108 | verbose--; | |
3109 | start = gg_cputime(); | |
3110 | memcpy(breakin_shadow, goal, sizeof(breakin_shadow)); | |
3111 | result = recursive_break(str, goal, move, 0, &goal_hash); | |
3112 | verbose = save_verbose; | |
3113 | tactical_nodes = get_reading_node_counter() - reading_nodes_when_called; | |
3114 | if (debug & DEBUG_BREAKIN) { | |
3115 | gprintf("%obreak_in %1M, result %s %1M (%d, %d nodes, %f seconds)\n", | |
3116 | str, result_to_string(result), *move, | |
3117 | nodes_connect, tactical_nodes, gg_cputime() - start); | |
3118 | goaldump(goal); | |
3119 | dump_stack(); | |
3120 | } | |
3121 | if (0) { | |
3122 | gprintf("%obreak_in %1m %d %1m ", str, result, *move); | |
3123 | dump_stack(); | |
3124 | goaldump(goal); | |
3125 | } | |
3126 | store_persistent_breakin_cache(BREAK_IN, str, &goal_hash, result, *move, | |
3127 | tactical_nodes, breakin_node_limit, | |
3128 | breakin_shadow); | |
3129 | ||
3130 | return result; | |
3131 | } | |
3132 | ||
3133 | ||
3134 | /* Externably callable frontend to recursive_block_off. | |
3135 | * Returns WIN if (str) cannot connect to the area goal[] (which may or may | |
3136 | * not contain stones), if the other color moves first. | |
3137 | */ | |
3138 | int | |
3139 | block_off(int str, const signed char goal[BOARDMAX], int *move) | |
3140 | { | |
3141 | int dummy_move; | |
3142 | int result; | |
3143 | int save_verbose; | |
3144 | int reading_nodes_when_called = get_reading_node_counter(); | |
3145 | double start = 0; | |
3146 | int tactical_nodes; | |
3147 | Hash_data goal_hash = goal_to_hashvalue(goal); | |
3148 | ||
3149 | if (move == NULL) | |
3150 | move = &dummy_move; | |
3151 | ||
3152 | nodes_connect = 0; | |
3153 | *move = PASS_MOVE; | |
3154 | ||
3155 | str = find_origin(str); | |
3156 | if (search_persistent_breakin_cache(BLOCK_OFF, str, &goal_hash, | |
3157 | breakin_node_limit, &result, move)) { | |
3158 | if (debug & DEBUG_BREAKIN) { | |
3159 | gprintf("Blocking off %1m from:\n", str); | |
3160 | goaldump(goal); | |
3161 | gprintf("Result cached: %s %1m\n", result_to_string(result), *move); | |
3162 | } | |
3163 | return result; | |
3164 | } | |
3165 | ||
3166 | save_verbose = verbose; | |
3167 | if (verbose > 0) | |
3168 | verbose--; | |
3169 | start = gg_cputime(); | |
3170 | memcpy(breakin_shadow, goal, sizeof(breakin_shadow)); | |
3171 | result = recursive_block(str, goal, move, 0, &goal_hash); | |
3172 | verbose = save_verbose; | |
3173 | tactical_nodes = get_reading_node_counter() - reading_nodes_when_called; | |
3174 | ||
3175 | if (debug & DEBUG_BREAKIN) { | |
3176 | gprintf("%oblock_off %1m, result %s %1m (%d, %d nodes, %f seconds)\n", | |
3177 | str, result_to_string(result), *move, | |
3178 | nodes_connect, tactical_nodes, gg_cputime() - start); | |
3179 | goaldump(goal); | |
3180 | dump_stack(); | |
3181 | } | |
3182 | if (0) { | |
3183 | gprintf("%oblock_off %1m %d %1m ", str, result, *move); | |
3184 | goaldump(goal); | |
3185 | dump_stack(); | |
3186 | } | |
3187 | store_persistent_breakin_cache(BLOCK_OFF, str, &goal_hash, result, *move, | |
3188 | tactical_nodes, breakin_node_limit, | |
3189 | breakin_shadow); | |
3190 | ||
3191 | return result; | |
3192 | } | |
3193 | ||
3194 | ||
3195 | /* Store a possibly expensive decision for later evaluation. The | |
3196 | * data getting stored should be self-explanatory. | |
3197 | * The job of the helper function is to | |
3198 | * - decide whether the spreading step will be allowed (typically | |
3199 | * depending on a latter) | |
3200 | * - add the relevant positions to the connection queue in case the test | |
3201 | * was successful. | |
3202 | * | |
3203 | * Elements in the heap are kept sorted according to smallest distance. | |
3204 | */ | |
3205 | static void | |
3206 | push_connection_heap_entry(struct connection_data *conn, int distance, | |
3207 | int coming_from, int target, | |
3208 | connection_helper_fn_ptr helper) | |
3209 | { | |
3210 | int k; | |
3211 | int parent; | |
3212 | struct heap_entry *new_entry = &conn->heap_data[conn->heap_data_size]; | |
3213 | ||
3214 | gg_assert(conn->heap_data_size < 4 * BOARDMAX); | |
3215 | gg_assert(conn->heap_size < BOARDMAX); | |
3216 | ||
3217 | /* Create new heap entry. */ | |
3218 | new_entry->distance = distance; | |
3219 | new_entry->coming_from = coming_from; | |
3220 | new_entry->target = target; | |
3221 | new_entry->helper = helper; | |
3222 | ||
3223 | /* And insert it into the heap. */ | |
3224 | conn->heap_data_size++; | |
3225 | ||
3226 | for (k = conn->heap_size++; k > 0; k = parent) { | |
3227 | parent = (k - 1) / 2; | |
3228 | if (conn->heap[parent]->distance <= distance) | |
3229 | break; | |
3230 | ||
3231 | conn->heap[k] = conn->heap[parent]; | |
3232 | } | |
3233 | ||
3234 | conn->heap[k] = new_entry; | |
3235 | } | |
3236 | ||
3237 | ||
3238 | /* Delete the first entry from the heap. */ | |
3239 | static void | |
3240 | pop_connection_heap_entry(struct connection_data *conn) | |
3241 | { | |
3242 | int k; | |
3243 | int child; | |
3244 | ||
3245 | conn->heap_size--; | |
3246 | for (k = 0; 2 * k + 1 < conn->heap_size; k = child) { | |
3247 | child = 2 * k + 1; | |
3248 | if (conn->heap[child]->distance > conn->heap[child + 1]->distance) | |
3249 | child++; | |
3250 | if (conn->heap[child]->distance >= conn->heap[conn->heap_size]->distance) | |
3251 | break; | |
3252 | ||
3253 | conn->heap[k] = conn->heap[child]; | |
3254 | } | |
3255 | ||
3256 | conn->heap[k] = conn->heap[conn->heap_size]; | |
3257 | } | |
3258 | ||
3259 | ||
3260 | #define ENQUEUE(conn, from, pos, dist, delta, v1, v2) \ | |
3261 | do { \ | |
3262 | if (dist < conn->distances[pos]) { \ | |
3263 | if (conn->distances[pos] == HUGE_CONNECTION_DISTANCE) \ | |
3264 | conn->queue[conn->queue_end++] = pos; \ | |
3265 | conn->distances[pos] = dist; \ | |
3266 | conn->deltas[pos] = delta; \ | |
3267 | conn->coming_from[pos] = from; \ | |
3268 | conn->vulnerable1[pos] = v1; \ | |
3269 | conn->vulnerable2[pos] = v2; \ | |
3270 | } \ | |
3271 | } while(0) | |
3272 | ||
3273 | #define ENQUEUE_STONE(conn, from, pos, dist, delta, v1, v2) \ | |
3274 | do { \ | |
3275 | int origin = find_origin(pos); \ | |
3276 | if (dist < conn->distances[origin]) { \ | |
3277 | if (conn->distances[origin] == HUGE_CONNECTION_DISTANCE) \ | |
3278 | conn->queue[conn->queue_end++] = origin; \ | |
3279 | conn->distances[origin] = dist; \ | |
3280 | conn->deltas[origin] = delta; \ | |
3281 | conn->coming_from[origin] = from; \ | |
3282 | conn->vulnerable1[origin] = v1; \ | |
3283 | conn->vulnerable2[origin] = v2; \ | |
3284 | if (origin == conn->target && dist < conn->cutoff_distance) \ | |
3285 | conn->cutoff_distance = dist - FP(0.0001); \ | |
3286 | } \ | |
3287 | } while(0) | |
3288 | ||
3289 | ||
3290 | static void | |
3291 | case_6_7_helper(struct connection_data *conn, int color) | |
3292 | { | |
3293 | struct heap_entry *data = conn->heap[0]; | |
3294 | int pos = data->coming_from; | |
3295 | int apos = data->target; | |
3296 | int other = OTHER_COLOR(color); | |
3297 | ||
3298 | if (ladder_capturable(apos, other)) | |
3299 | ENQUEUE(conn, pos, apos, data->distance, FP(0.6), apos, NO_MOVE); | |
3300 | else { | |
3301 | int this_delta | |
3302 | = FP(0.85) + FP(0.05) * gg_min(approxlib(apos, other, 5, NULL), 5); | |
3303 | ENQUEUE(conn, pos, apos, data->distance + this_delta - FP(0.6), this_delta, | |
3304 | NO_MOVE, NO_MOVE); | |
3305 | } | |
3306 | } | |
3307 | ||
3308 | ||
3309 | static void | |
3310 | case_9_10_helper(struct connection_data *conn, int color) | |
3311 | { | |
3312 | struct heap_entry *data = conn->heap[0]; | |
3313 | int pos = data->coming_from; | |
3314 | int apos = data->target; | |
3315 | ||
3316 | UNUSED(color); | |
3317 | ||
3318 | if (no_escape_from_ladder(apos)) | |
3319 | ENQUEUE_STONE(conn, pos, apos, data->distance, FP(0.3), NO_MOVE, NO_MOVE); | |
3320 | else { | |
3321 | if (conn->speculative) { | |
3322 | ENQUEUE_STONE(conn, pos, apos, data->distance + FP(0.7), FP(1.0), | |
3323 | NO_MOVE, NO_MOVE); | |
3324 | } | |
3325 | else { | |
3326 | ENQUEUE_STONE(conn, pos, apos, data->distance + FP(0.8), FP(1.1), | |
3327 | NO_MOVE, NO_MOVE); | |
3328 | } | |
3329 | } | |
3330 | } | |
3331 | ||
3332 | ||
3333 | static void | |
3334 | case_16_17_18_helper(struct connection_data *conn, int color) | |
3335 | { | |
3336 | struct heap_entry *data = conn->heap[0]; | |
3337 | int pos = data->coming_from; | |
3338 | int bpos = data->target; | |
3339 | int apos = SOUTH(gg_min(pos, bpos)); | |
3340 | int gpos = NORTH(gg_max(pos, bpos)); | |
3341 | int other = OTHER_COLOR(color); | |
3342 | ||
3343 | if (board[apos] == EMPTY | |
3344 | && does_secure_through_ladder(color, bpos, apos)) | |
3345 | ENQUEUE(conn, pos, bpos, data->distance, FP(1.0), apos, NO_MOVE); | |
3346 | else if (board[gpos] == EMPTY | |
3347 | && does_secure_through_ladder(color, bpos, gpos)) | |
3348 | ENQUEUE(conn, pos, bpos, data->distance, FP(1.0), gpos, NO_MOVE); | |
3349 | else if (conn->distances[bpos] > data->distance + FP(0.3)) { | |
3350 | if (board[apos] == EMPTY | |
3351 | && board[gpos] == other | |
3352 | && countlib(gpos) <= 3) | |
3353 | ENQUEUE(conn, pos, bpos, data->distance + FP(0.3), FP(1.0), | |
3354 | apos, NO_MOVE); | |
3355 | else if (board[gpos] == EMPTY | |
3356 | && board[apos] == other | |
3357 | && countlib(apos) <= 3) | |
3358 | ENQUEUE(conn, pos, bpos, data->distance + FP(0.3), FP(1.0), | |
3359 | gpos, NO_MOVE); | |
3360 | else | |
3361 | ENQUEUE(conn, pos, bpos, data->distance + FP(0.6), FP(0.9), | |
3362 | NO_MOVE, NO_MOVE); | |
3363 | } | |
3364 | } | |
3365 | ||
3366 | ||
3367 | /* Do the real work of computing connection distances. | |
3368 | * This is a rough approximation of the number of moves required to secure | |
3369 | * a connection. We also compute delta values which are intended to tell how | |
3370 | * big difference a particular move locally has on the connection | |
3371 | * distance. However, remember that this is only a heuristic with the | |
3372 | * sole purpose of helping to find relevant moves for connection | |
3373 | * problems. | |
3374 | * | |
3375 | * The algorithm is to propagate connection values outwards using a | |
3376 | * breadth-first searching strategy, implemented through an implicitly | |
3377 | * sorted queue. The propagation to new vertices depends on | |
3378 | * geometrical features with significance for connections. E.g. a | |
3379 | * bamboo joint is recognized and the distance added when passing | |
3380 | * through it is small. New points are added to the queue through the | |
3381 | * ENQUEUE macro above. This checks whether the point has already been | |
3382 | * entered on the queue and updates the distance and delta values if | |
3383 | * the previous ones were worse. When a stone is entered, all stones | |
3384 | * of the string are added to the queue simultaneously. | |
3385 | * | |
3386 | * (target) is the other string when called from find_connection_moves(). | |
3387 | * (It can be set to NO_MOVE otherwise.) | |
3388 | * | |
3389 | * The propagation is inhibited when the distance becomes too large, | |
3390 | * or larger than the shortest path found to the target so far. | |
3391 | * | |
3392 | * | |
3393 | * The purpose of the fields called vulnerable is to keep track of | |
3394 | * points where the attacker can threaten an individual | |
3395 | * connection. For example the diagonal formation | |
3396 | * | |
3397 | * .O | |
3398 | * O. | |
3399 | * | |
3400 | * is considered a small distance link but both the empty vertices are | |
3401 | * marked as vulnerable. Thus if we are computing connection distance | |
3402 | * from the lower left O in this diagram, | |
3403 | * | |
3404 | * XXX XXX | |
3405 | * .O. .O. | |
3406 | * O.O OaO | |
3407 | * .X. .X. | |
3408 | * | |
3409 | * the distance to the middle O is small but the second diagonal link | |
3410 | * to the lower right O stone is not given a small distance since a | |
3411 | * had already been marked as vulnerable. | |
3412 | * | |
3413 | * It should also be pointed out that this reasoning is not relevant | |
3414 | * in this position where X has no cutting potential, | |
3415 | * | |
3416 | * XXX XXX | |
3417 | * .O. .O. | |
3418 | * O.O OaO | |
3419 | * ... ... | |
3420 | * | |
3421 | * That is because there is a pattern directly recognizing the safe | |
3422 | * link between the two lower stones, without taking the longer road | |
3423 | * over the two diagonal links. | |
3424 | * | |
3425 | * (color) is the color for which we are computing connection distances, | |
3426 | * (target) the position we want to reach (can be set to NO_MOVE), | |
3427 | * (*conn) has to have the queue initialized with the positions | |
3428 | * from which we want to know the distances, | |
3429 | * (cutoff_distance) is the highest distance before we give up, | |
3430 | * (speculative) controls some special cases in the propagation rules | |
3431 | * below. | |
3432 | * | |
3433 | * As an optimization, new points are either added directly via the ENQUEUE | |
3434 | * macro if the necessary test is an immediate (usually purely geometric) | |
3435 | * check, or if the decision is more expensive (usually depending on a | |
3436 | * ladder), it gets postponed and stored via push_connection_heap_entry() | |
3437 | * for later evaluation. | |
3438 | */ | |
3439 | ||
3440 | void | |
3441 | spread_connection_distances(int color, struct connection_data *conn) | |
3442 | { | |
3443 | int other = OTHER_COLOR(color); | |
3444 | int stones[MAX_BOARD * MAX_BOARD]; | |
3445 | int num_stones = 0; | |
3446 | int stone = 0; | |
3447 | ||
3448 | /* Loop until we reach the end of the queue. */ | |
3449 | while (conn->queue_start < conn->queue_end || conn->heap_size > 0) { | |
3450 | int k; | |
3451 | int pos; | |
3452 | int distance; | |
3453 | ||
3454 | /* Delete heap entries for positions that have already been reached | |
3455 | * with smaller distance. | |
3456 | */ | |
3457 | while (conn->heap_size > 0 | |
3458 | && conn->heap[0]->distance >= conn->distances[conn->heap[0]->target]) | |
3459 | pop_connection_heap_entry(conn); | |
3460 | ||
3461 | if (stone == num_stones) { | |
3462 | int best_index = -1; | |
3463 | int smallest_dist = HUGE_CONNECTION_DISTANCE; | |
3464 | ||
3465 | if (conn->queue_start == conn->queue_end) { | |
3466 | if (conn->heap_size > 0) { | |
3467 | conn->heap[0]->helper(conn, color); | |
3468 | pop_connection_heap_entry(conn); | |
3469 | } | |
3470 | ||
3471 | continue; | |
3472 | } | |
3473 | ||
3474 | gg_assert(conn->queue_end <= MAX_BOARD * MAX_BOARD); | |
3475 | ||
3476 | /* Find the smallest distance among the queued points. */ | |
3477 | for (k = conn->queue_start; k < conn->queue_end; k++) { | |
3478 | if (conn->distances[conn->queue[k]] < smallest_dist) { | |
3479 | smallest_dist = conn->distances[conn->queue[k]]; | |
3480 | best_index = k; | |
3481 | } | |
3482 | } | |
3483 | ||
3484 | /* Exchange the best point with the first element in the queue. */ | |
3485 | if (best_index != conn->queue_start) { | |
3486 | int temp = conn->queue[conn->queue_start]; | |
3487 | conn->queue[conn->queue_start] = conn->queue[best_index]; | |
3488 | conn->queue[best_index] = temp; | |
3489 | } | |
3490 | ||
3491 | /* If the first element in heap has smaller distance than the | |
3492 | * smallest we have found so far, call the relevant helper function | |
3493 | * now, and delete the heap entry. | |
3494 | */ | |
3495 | if (conn->heap_size > 0 && conn->heap[0]->distance < smallest_dist) { | |
3496 | conn->heap[0]->helper(conn, color); | |
3497 | pop_connection_heap_entry(conn); | |
3498 | continue; | |
3499 | } | |
3500 | ||
3501 | /* Now we are ready to pick the first element in the queue and | |
3502 | * process it. | |
3503 | */ | |
3504 | pos = conn->queue[conn->queue_start++]; | |
3505 | if (board[pos] != EMPTY) { | |
3506 | num_stones = findstones(pos, MAX_BOARD * MAX_BOARD, stones); | |
3507 | pos = stones[0]; | |
3508 | stone = 1; | |
3509 | } | |
3510 | } | |
3511 | else { | |
3512 | pos = stones[stone++]; | |
3513 | conn->distances[pos] = conn->distances[stones[0]]; | |
3514 | conn->deltas[pos] = conn->deltas[stones[0]]; | |
3515 | conn->coming_from[pos] = conn->coming_from[stones[0]]; | |
3516 | conn->vulnerable1[pos] = conn->vulnerable1[stones[0]]; | |
3517 | conn->vulnerable2[pos] = conn->vulnerable2[stones[0]]; | |
3518 | } | |
3519 | ||
3520 | /* No further propagation if the distance is too large. */ | |
3521 | distance = conn->distances[pos]; | |
3522 | if (distance > conn->cutoff_distance) | |
3523 | break; | |
3524 | ||
3525 | /* Search for new vertices to propagate to. */ | |
3526 | if (board[pos] == color) { | |
3527 | for (k = 0; k < 4; k++) { | |
3528 | /* List of relative coordinates. (pos) is marked by *. | |
3529 | * | |
3530 | * jef. | |
3531 | * igb. | |
3532 | * kh*ac | |
3533 | * .... | |
3534 | * | |
3535 | */ | |
3536 | int right = delta[k]; | |
3537 | int up = delta[(k+1)%4]; | |
3538 | ||
3539 | /* FIXME: Compactify this list. */ | |
3540 | int apos = pos + right; | |
3541 | int bpos = pos + right + up; | |
3542 | int cpos = pos + 2 * right; | |
3543 | int epos = pos + 2*up; | |
3544 | int fpos = pos + right + 2*up; | |
3545 | int gpos = pos + up; | |
3546 | int hpos = pos - right; | |
3547 | int ipos = pos - right + up; | |
3548 | int jpos = pos - right + 2 * up; | |
3549 | int kpos = pos - 2 * right; | |
3550 | ||
3551 | /* Case 1. "a" is empty and would be suicide for the opponent. */ | |
3552 | if (board[apos] == EMPTY && is_suicide(apos, other)) | |
3553 | ENQUEUE(conn, pos, apos, distance, FP(0.0), apos, NO_MOVE); | |
3554 | ||
3555 | /* Case 2. "a" is empty and would be self atari for the opponent. */ | |
3556 | if (board[apos] == EMPTY | |
3557 | && conn->distances[apos] > distance + FP(0.1) | |
3558 | && is_self_atari(apos, other)) { | |
3559 | int lib; | |
3560 | int vulnerable1 = NO_MOVE; | |
3561 | int vulnerable2 = NO_MOVE; | |
3562 | if (approxlib(apos, other, 1, &lib) >= 1) { | |
3563 | if (approxlib(lib, other, 2, NULL) > 2) | |
3564 | vulnerable1 = lib; | |
3565 | if (countlib(pos) == 2) { | |
3566 | int i; | |
3567 | for (i = 0; i < 4; i++) { | |
3568 | if (board[lib + delta[i]] == EMPTY | |
3569 | && lib + delta[i] != apos | |
3570 | && trymove(lib + delta[i], other, | |
3571 | "compute_connection_distances", pos)) { | |
3572 | if (ladder_capture(pos, NULL)) { | |
3573 | vulnerable2 = lib + delta[i]; | |
3574 | popgo(); | |
3575 | break; | |
3576 | } | |
3577 | popgo(); | |
3578 | } | |
3579 | } | |
3580 | } | |
3581 | } | |
3582 | ||
3583 | if (!common_vulnerabilities(conn->vulnerable1[pos], | |
3584 | conn->vulnerable2[pos], | |
3585 | vulnerable1, vulnerable2, color)) { | |
3586 | ENQUEUE(conn, pos, apos, distance + FP(0.1), FP(0.1), | |
3587 | vulnerable1, vulnerable2); | |
3588 | } | |
3589 | } | |
3590 | ||
3591 | /* Case 3. Bamboo joint of "*" + "a" to "e" + "f" through "b" and "g". | |
3592 | * Notice that the order of these tests is significant. We must | |
3593 | * check bpos before fpos and epos to avoid accessing memory | |
3594 | * outside the board array. (Notice that fpos is two steps away | |
3595 | * from pos, which we know is on the board.) | |
3596 | */ | |
3597 | if (board[apos] == color && board[bpos] == EMPTY | |
3598 | && board[fpos] == color && board[epos] == color | |
3599 | && board[gpos] == EMPTY) { | |
3600 | ENQUEUE(conn, pos, bpos, distance + FP(0.1), FP(0.1), | |
3601 | NO_MOVE, NO_MOVE); | |
3602 | ENQUEUE(conn, pos, gpos, distance + FP(0.1), FP(0.1), | |
3603 | NO_MOVE, NO_MOVE); | |
3604 | } | |
3605 | ||
3606 | /* Case 4. Diagonal connection to another stone "b" through | |
3607 | * empty vertices "a" and "g". | |
3608 | */ | |
3609 | if (board[bpos] == color | |
3610 | && board[apos] == EMPTY | |
3611 | && board[gpos] == EMPTY | |
3612 | && !common_vulnerabilities(conn->vulnerable1[pos], | |
3613 | conn->vulnerable2[pos], | |
3614 | apos, gpos, color) | |
3615 | && conn->distances[bpos] > distance + FP(0.1)) { | |
3616 | #if 0 | |
3617 | ENQUEUE(conn, pos, apos, distance + FP(0.2), FP(0.2), | |
3618 | NO_MOVE, NO_MOVE); | |
3619 | ENQUEUE(conn, pos, gpos, distance + FP(0.2), FP(0.2), | |
3620 | NO_MOVE, NO_MOVE); | |
3621 | #endif | |
3622 | ENQUEUE_STONE(conn, pos, bpos, distance + FP(0.1), FP(0.1), | |
3623 | apos, gpos); | |
3624 | } | |
3625 | ||
3626 | /* Case 5. Almost bamboo joint. | |
3627 | * | |
3628 | */ | |
3629 | if (board[gpos] == EMPTY | |
3630 | && board[epos] == color | |
3631 | && conn->distances[epos] > distance + FP(0.2) | |
3632 | && approxlib(gpos, other, 3, NULL) <= 2) { | |
3633 | if (board[bpos] == EMPTY | |
3634 | && approxlib(bpos, color, 3, NULL) >= 3 | |
3635 | && (board[apos] == color | |
3636 | || (board[apos] == EMPTY | |
3637 | && countlib(pos) > 2 | |
3638 | && !common_vulnerabilities(conn->vulnerable1[pos], | |
3639 | conn->vulnerable2[pos], | |
3640 | apos, gpos, color) | |
3641 | && approxlib(apos, other, 3, NULL) <= 2)) | |
3642 | && (board[fpos] == color | |
3643 | || (board[fpos] == EMPTY | |
3644 | && countlib(epos) > 2 | |
3645 | && !common_vulnerabilities(conn->vulnerable1[pos], | |
3646 | conn->vulnerable2[pos], | |
3647 | fpos, gpos, color) | |
3648 | && approxlib(fpos, other, 3, NULL) <= 2))) { | |
3649 | if (board[apos] == EMPTY && board[fpos] == EMPTY) { | |
3650 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3651 | apos, fpos); | |
3652 | } | |
3653 | else if (board[apos] == EMPTY && board[fpos] != EMPTY) { | |
3654 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3655 | apos, NO_MOVE); | |
3656 | } | |
3657 | else if (board[apos] != EMPTY && board[fpos] == EMPTY) { | |
3658 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3659 | fpos, NO_MOVE); | |
3660 | } | |
3661 | else if (board[apos] != EMPTY && board[fpos] != EMPTY) { | |
3662 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3663 | NO_MOVE, NO_MOVE); | |
3664 | } | |
3665 | } | |
3666 | ||
3667 | if (board[ipos] == EMPTY | |
3668 | && approxlib(ipos, color, 3, NULL) >= 3 | |
3669 | && (board[hpos] == color | |
3670 | || (board[hpos] == EMPTY | |
3671 | && countlib(pos) > 2 | |
3672 | && !common_vulnerabilities(conn->vulnerable1[pos], | |
3673 | conn->vulnerable2[pos], | |
3674 | hpos, gpos, color) | |
3675 | && approxlib(hpos, other, 3, NULL) <= 2)) | |
3676 | && (board[jpos] == color | |
3677 | || (board[jpos] == EMPTY | |
3678 | && countlib(epos) > 2 | |
3679 | && !common_vulnerabilities(conn->vulnerable1[pos], | |
3680 | conn->vulnerable2[pos], | |
3681 | jpos, gpos, color) | |
3682 | && approxlib(jpos, other, 3, NULL) <= 2))) { | |
3683 | if (board[hpos] == EMPTY && board[jpos] == EMPTY) { | |
3684 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3685 | hpos, jpos); | |
3686 | } | |
3687 | else if (board[hpos] == EMPTY && board[jpos] != EMPTY) { | |
3688 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3689 | hpos, NO_MOVE); | |
3690 | } | |
3691 | else if (board[hpos] != EMPTY && board[jpos] == EMPTY) { | |
3692 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3693 | jpos, NO_MOVE); | |
3694 | } | |
3695 | else if (board[hpos] != EMPTY && board[jpos] != EMPTY) { | |
3696 | ENQUEUE_STONE(conn, pos, epos, distance + FP(0.2), FP(0.2), | |
3697 | NO_MOVE, NO_MOVE); | |
3698 | } | |
3699 | } | |
3700 | } | |
3701 | ||
3702 | /* Case 6. "a" is empty and an opponent move can be captured | |
3703 | * in a ladder. | |
3704 | * | |
3705 | * Case 7. "a" is empty. | |
3706 | */ | |
3707 | if (board[apos] == EMPTY && conn->distances[apos] > distance + FP(0.6)) { | |
3708 | push_connection_heap_entry(conn, distance + FP(0.6), pos, apos, | |
3709 | case_6_7_helper); | |
3710 | } | |
3711 | ||
3712 | /* Case 8. Adjacent opponent stone at "a" which can't avoid atari. | |
3713 | */ | |
3714 | if (board[apos] == other | |
3715 | && conn->distances[apos] > distance + FP(0.1) | |
3716 | && no_escape_from_atari(apos)) { | |
3717 | ENQUEUE_STONE(conn, pos, apos, distance + FP(0.1), FP(0.1), | |
3718 | NO_MOVE, NO_MOVE); | |
3719 | } | |
3720 | ||
3721 | /* Case 9. Adjacent opponent stone at "a" which can't avoid | |
3722 | * ladder capture. | |
3723 | * | |
3724 | * Case 10. "a" is occupied by opponent. | |
3725 | */ | |
3726 | if (board[apos] == other && conn->distances[apos] > distance + FP(0.3)) { | |
3727 | push_connection_heap_entry(conn, distance + FP(0.3), pos, apos, | |
3728 | case_9_10_helper); | |
3729 | } | |
3730 | ||
3731 | /* Case 11. Diagonal connection to empty vertex "b" through | |
3732 | * empty vertex "a" or "g", which makes "a" or "g" self-atari | |
3733 | * for opponent. | |
3734 | */ | |
3735 | if (board[bpos] == EMPTY | |
3736 | && board[apos] == EMPTY | |
3737 | && conn->distances[bpos] > distance + FP(1.1) | |
3738 | && does_secure(color, bpos, apos)) { | |
3739 | ENQUEUE(conn, pos, bpos, distance + FP(1.1), FP(1.0), apos, NO_MOVE); | |
3740 | } | |
3741 | ||
3742 | if (board[bpos] == EMPTY | |
3743 | && board[gpos] == EMPTY | |
3744 | && conn->distances[bpos] > distance + FP(1.1) | |
3745 | && does_secure(color, bpos, gpos)) { | |
3746 | ENQUEUE(conn, pos, bpos, distance + FP(1.1), FP(1.0), gpos, NO_MOVE); | |
3747 | } | |
3748 | ||
3749 | /* Case 12. One-space jump to empty vertex "e" through empty | |
3750 | * vertex "g", which makes "g" self-atari for opponent. | |
3751 | */ | |
3752 | if (board[gpos] == EMPTY | |
3753 | && board[epos] == EMPTY | |
3754 | && conn->distances[epos] > distance + FP(1.1) | |
3755 | && does_secure(color, epos, gpos)) { | |
3756 | ENQUEUE(conn, pos, epos, distance + FP(1.1), FP(1.0), gpos, NO_MOVE); | |
3757 | } | |
3758 | ||
3759 | /* Case 13. One-space jump to empty vertex "e" through empty | |
3760 | * vertex "g", making a bamboo joint. | |
3761 | */ | |
3762 | if (board[gpos] == EMPTY | |
3763 | && board[epos] == EMPTY | |
3764 | && conn->distances[epos] > distance + FP(1.1) | |
3765 | && ((board[apos] == color && board[fpos] == color | |
3766 | && board[bpos] == EMPTY) | |
3767 | || (board[hpos] == color && board[jpos] == color | |
3768 | && board[ipos] == EMPTY))) { | |
3769 | ENQUEUE(conn, pos, epos, distance + FP(1.1), FP(1.0), gpos, NO_MOVE); | |
3770 | } | |
3771 | ||
3772 | /* Case 14. Diagonal connection to empty vertex "b" through | |
3773 | * empty vertices "a" and "g". | |
3774 | */ | |
3775 | if (board[bpos] == EMPTY | |
3776 | && board[apos] == EMPTY && board[gpos] == EMPTY | |
3777 | && conn->distances[bpos] > distance + FP(1.3)) { | |
3778 | ENQUEUE(conn, pos, bpos, distance + FP(1.3), FP(1.0), apos, gpos); | |
3779 | } | |
3780 | ||
3781 | /* Case 15. Keima to "f" or "j" on edge. and one space jump on | |
3782 | * first or second line. | |
3783 | */ | |
3784 | if (board[apos] == EMPTY | |
3785 | && board[bpos] == EMPTY | |
3786 | && board[gpos] == EMPTY | |
3787 | && board[epos] == EMPTY | |
3788 | && board[fpos] == EMPTY | |
3789 | && (conn->distances[fpos] > distance + FP(1.3) | |
3790 | || conn->distances[epos] > distance + FP(1.3)) | |
3791 | && countlib(pos) >= 3 | |
3792 | && (!ON_BOARD(cpos) || !ON_BOARD(hpos))) { | |
3793 | ENQUEUE(conn, pos, fpos, distance + FP(1.3), FP(1.0), | |
3794 | NO_MOVE, NO_MOVE); | |
3795 | ENQUEUE(conn, pos, epos, distance + FP(1.3), FP(1.0), | |
3796 | NO_MOVE, NO_MOVE); | |
3797 | } | |
3798 | ||
3799 | if (board[hpos] == EMPTY | |
3800 | && board[ipos] == EMPTY | |
3801 | && board[gpos] == EMPTY | |
3802 | && board[epos] == EMPTY | |
3803 | && board[jpos] == EMPTY | |
3804 | && (conn->distances[jpos] > distance + FP(1.3) | |
3805 | || conn->distances[epos] > distance + FP(1.3)) | |
3806 | && countlib(pos) >= 3 | |
3807 | && (!ON_BOARD(apos) || !ON_BOARD(kpos))) { | |
3808 | ENQUEUE(conn, pos, jpos, distance + FP(1.3), FP(1.0), | |
3809 | NO_MOVE, NO_MOVE); | |
3810 | ENQUEUE(conn, pos, epos, distance + FP(1.3), FP(1.0), | |
3811 | NO_MOVE, NO_MOVE); | |
3812 | } | |
3813 | ||
3814 | /* Case 16. Diagonal connection to empty vertex "b" through | |
3815 | * empty vertex "a" or "g", which allows opponent move at "a" | |
3816 | * or "g" to be captured in a ladder. | |
3817 | * | |
3818 | * Case 17. Diagonal connection to empty vertex "b" through | |
3819 | * one empty and one opponent vertex "a" and "g", where | |
3820 | * the opponent stone is short of liberties. | |
3821 | * | |
3822 | * Case 18. Diagonal connection to empty vertex "b" through | |
3823 | * empty vertex "a" or "g", with no particular properties. | |
3824 | */ | |
3825 | if (board[bpos] == EMPTY | |
3826 | && (board[apos] == EMPTY || board[gpos] == EMPTY) | |
3827 | && conn->distances[bpos] > distance + FP(1.2)) { | |
3828 | push_connection_heap_entry(conn, distance + FP(1.2), pos, bpos, | |
3829 | case_16_17_18_helper); | |
3830 | } | |
3831 | ||
3832 | /* Case 19. Clamp at "e" of single stone at "g". */ | |
3833 | if (board[gpos] == other | |
3834 | && board[epos] == EMPTY | |
3835 | && conn->distances[epos] > distance + FP(2.0) | |
3836 | && countstones(gpos) == 1) { | |
3837 | ENQUEUE(conn, pos, epos, distance + FP(2.0), FP(1.0), | |
3838 | NO_MOVE, NO_MOVE); | |
3839 | } | |
3840 | ||
3841 | /* Case 20. Diagonal connection to empty vertex "b" through | |
3842 | * opponent stones "a" or "g" with few liberties. | |
3843 | */ | |
3844 | if (board[bpos] == EMPTY | |
3845 | && board[apos] == other | |
3846 | && board[gpos] == other | |
3847 | && conn->distances[bpos] > distance + FP(2.0) | |
3848 | && (countlib(apos) + countlib(gpos) <= 6)) { | |
3849 | ENQUEUE(conn, pos, bpos, distance + FP(2.0), FP(1.0), | |
3850 | NO_MOVE, NO_MOVE); | |
3851 | } | |
3852 | ||
3853 | /* Case 21. Diagonal connection to own stone "b" through | |
3854 | * opponent stones "a" or "g" with few liberties. | |
3855 | */ | |
3856 | if (board[bpos] == color | |
3857 | && board[apos] == other | |
3858 | && board[gpos] == other | |
3859 | && conn->distances[bpos] > distance + FP(2.0) | |
3860 | && (countlib(apos) + countlib(gpos) <= 5)) { | |
3861 | ENQUEUE_STONE(conn, pos, bpos, distance + FP(2.0), FP(1.0), | |
3862 | NO_MOVE, NO_MOVE); | |
3863 | } | |
3864 | } | |
3865 | } | |
3866 | else if (board[pos] == EMPTY | |
3867 | || (board[pos] == other | |
3868 | && countlib(pos) <= 2 | |
3869 | && no_escape_from_ladder(pos))) { | |
3870 | for (k = 0; k < 4; k++) { | |
3871 | /* List of relative coordinates. (pos) is marked by *. | |
3872 | * | |
3873 | * jef. | |
3874 | * igb. | |
3875 | * kh*ac | |
3876 | * .d. | |
3877 | * | |
3878 | */ | |
3879 | int right = delta[k]; | |
3880 | int up = delta[(k+1)%4]; | |
3881 | ||
3882 | /* FIXME: Compactify this list. */ | |
3883 | int apos = pos + right; | |
3884 | int bpos = pos + right + up; | |
3885 | #if 0 | |
3886 | int cpos = pos + 2 * right; | |
3887 | int epos = pos + 2*up; | |
3888 | int fpos = pos + right + 2*up; | |
3889 | #endif | |
3890 | int gpos = pos + up; | |
3891 | #if 0 | |
3892 | int hpos = pos - right; | |
3893 | int ipos = pos - right + up; | |
3894 | int jpos = pos - right + 2 * up; | |
3895 | int kpos = pos - 2 * right; | |
3896 | #endif | |
3897 | ||
3898 | if (board[apos] == color) { | |
3899 | ENQUEUE_STONE(conn, pos, apos, distance, FP(0.0), | |
3900 | conn->vulnerable1[pos], conn->vulnerable2[pos]); | |
3901 | } | |
3902 | else if (board[apos] == EMPTY) { | |
3903 | int this_delta | |
3904 | = FP(0.8) + FP(0.05) * gg_min(approxlib(apos, other, 6, NULL), 6); | |
3905 | ENQUEUE(conn, pos, apos, distance + this_delta, this_delta, | |
3906 | NO_MOVE, NO_MOVE); | |
3907 | } | |
3908 | else if (board[apos] == other) { | |
3909 | ENQUEUE_STONE(conn, pos, apos, distance + FP(1.0), FP(1.0), | |
3910 | NO_MOVE, NO_MOVE); | |
3911 | } | |
3912 | ||
3913 | /* Case 1. Diagonal connection to empty vertex "b" through | |
3914 | * empty vertices "a" and "g". | |
3915 | */ | |
3916 | if (board[bpos] == EMPTY | |
3917 | && board[apos] == EMPTY | |
3918 | && board[gpos] == EMPTY | |
3919 | && conn->distances[bpos] > distance + FP(1.5)) { | |
3920 | ENQUEUE(conn, pos, bpos, distance + FP(1.5), FP(1.0), | |
3921 | NO_MOVE, NO_MOVE); | |
3922 | } | |
3923 | ||
3924 | /* Case 2. Diagonal connection to friendly stone at "b" through | |
3925 | * empty vertices "a" and "g". | |
3926 | */ | |
3927 | if (board[bpos] == color | |
3928 | && board[apos] == EMPTY | |
3929 | && board[gpos] == EMPTY | |
3930 | && conn->distances[bpos] > distance + FP(1.3)) { | |
3931 | ENQUEUE_STONE(conn, pos, bpos, distance + FP(1.3), FP(1.0), | |
3932 | NO_MOVE, NO_MOVE); | |
3933 | } | |
3934 | } | |
3935 | } | |
3936 | } | |
3937 | } | |
3938 | ||
3939 | ||
3940 | void | |
3941 | sort_connection_queue_tail(struct connection_data *conn) | |
3942 | { | |
3943 | int k; | |
3944 | ||
3945 | for (k = conn->queue_start; k < conn->queue_end - 1; k++) { | |
3946 | int i; | |
3947 | int best_index = k; | |
3948 | int smallest_dist = conn->distances[conn->queue[k]]; | |
3949 | ||
3950 | for (i = k + 1; i < conn->queue_end; i++) { | |
3951 | if (conn->distances[conn->queue[i]] < smallest_dist) { | |
3952 | best_index = i; | |
3953 | smallest_dist = conn->distances[conn->queue[i]]; | |
3954 | } | |
3955 | } | |
3956 | ||
3957 | if (best_index != k) { | |
3958 | int temp = conn->queue[k]; | |
3959 | conn->queue[k] = conn->queue[best_index]; | |
3960 | conn->queue[best_index] = temp; | |
3961 | } | |
3962 | } | |
3963 | } | |
3964 | ||
3965 | ||
3966 | /* Replace string origins in a connection queue with complete sets of | |
3967 | * corresponding string stones. | |
3968 | */ | |
3969 | void | |
3970 | expand_connection_queue(struct connection_data *conn) | |
3971 | { | |
3972 | int k; | |
3973 | int full_queue[BOARDMAX]; | |
3974 | int full_queue_position = 0; | |
3975 | int full_queue_start = 0; | |
3976 | ||
3977 | for (k = 0; k < conn->queue_end; k++) { | |
3978 | if (k == conn->queue_start) | |
3979 | full_queue_start = full_queue_position; | |
3980 | ||
3981 | if (board[conn->queue[k]] == EMPTY) | |
3982 | full_queue[full_queue_position++] = conn->queue[k]; | |
3983 | else { | |
3984 | full_queue_position += findstones(conn->queue[k], | |
3985 | MAX_BOARD * MAX_BOARD, | |
3986 | full_queue + full_queue_position); | |
3987 | } | |
3988 | } | |
3989 | ||
3990 | conn->queue_start = full_queue_start; | |
3991 | conn->queue_end = full_queue_position; | |
3992 | memcpy(conn->queue, full_queue, conn->queue_end * sizeof(int)); | |
3993 | } | |
3994 | ||
3995 | ||
3996 | /* Initialize distance and delta values so that the former are | |
3997 | * everywhere huge and the latter everywhere zero. | |
3998 | */ | |
3999 | static void | |
4000 | clear_connection_data(struct connection_data *conn) | |
4001 | { | |
4002 | int pos; | |
4003 | ||
4004 | conn->queue_start = 0; | |
4005 | conn->queue_end = 0; | |
4006 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
4007 | conn->distances[pos] = HUGE_CONNECTION_DISTANCE; | |
4008 | conn->deltas[pos] = FP(0.0); | |
4009 | conn->coming_from[pos] = NO_MOVE; | |
4010 | conn->vulnerable1[pos] = NO_MOVE; | |
4011 | conn->vulnerable2[pos] = NO_MOVE; | |
4012 | } | |
4013 | ||
4014 | conn->heap_data_size = 0; | |
4015 | conn->heap_size = 0; | |
4016 | } | |
4017 | ||
4018 | ||
4019 | /* Compute the connection distances from string (str) to nearby | |
4020 | * vertices, until we reach target or the distance gets too high. | |
4021 | */ | |
4022 | void | |
4023 | compute_connection_distances(int str, int target, int cutoff, | |
4024 | struct connection_data *conn, | |
4025 | int speculative) | |
4026 | { | |
4027 | int color = board[str]; | |
4028 | ||
4029 | clear_connection_data(conn); | |
4030 | ||
4031 | /* Add the origin of the initial string to the queue. */ | |
4032 | add_to_start_queue(find_origin(str), FP(0.0), conn); | |
4033 | ||
4034 | conn->target = target; | |
4035 | conn->cutoff_distance = cutoff; | |
4036 | conn->speculative = speculative; | |
4037 | ||
4038 | spread_connection_distances(color, conn); | |
4039 | } | |
4040 | ||
4041 | ||
4042 | /* Print the connection distances in a struct connection_data. */ | |
4043 | void | |
4044 | print_connection_distances(struct connection_data *conn) | |
4045 | { | |
4046 | int i, j; | |
4047 | int ch; | |
4048 | int pos; | |
4049 | ||
4050 | fprintf(stderr, " "); | |
4051 | for (j = 0, ch = 'A'; j < board_size; j++, ch++) { | |
4052 | if (ch == 'I') | |
4053 | ch++; | |
4054 | fprintf(stderr, " %c ", ch); | |
4055 | } | |
4056 | fprintf(stderr, "\n"); | |
4057 | ||
4058 | for (i = 0; i < board_size; i++) { | |
4059 | fprintf(stderr, "%2d ", board_size - i); | |
4060 | for (j = 0; j < board_size; j++) { | |
4061 | pos = POS(i, j); | |
4062 | if (conn->distances[pos] == HUGE_CONNECTION_DISTANCE) { | |
4063 | if (board[pos] == WHITE) | |
4064 | fprintf(stderr, " O "); | |
4065 | if (board[pos] == BLACK) | |
4066 | fprintf(stderr, " X "); | |
4067 | if (board[pos] == EMPTY) | |
4068 | fprintf(stderr, " . "); | |
4069 | } | |
4070 | else { | |
4071 | fprintf(stderr, "%3.1f ", FIXED_TO_FLOAT(conn->distances[pos])); | |
4072 | } | |
4073 | } | |
4074 | fprintf(stderr, "\n"); | |
4075 | } | |
4076 | fprintf(stderr, "\n"); | |
4077 | ||
4078 | fprintf(stderr, "Vulnerable:\n"); | |
4079 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
4080 | if (conn->distances[pos] < HUGE_CONNECTION_DISTANCE | |
4081 | && (conn->vulnerable1[pos] != NO_MOVE | |
4082 | || conn->vulnerable2[pos] != NO_MOVE)) { | |
4083 | gprintf(" %1m:", pos); | |
4084 | if (conn->vulnerable1[pos] != NO_MOVE) | |
4085 | gprintf(" %1m", conn->vulnerable1[pos]); | |
4086 | if (conn->vulnerable2[pos] != NO_MOVE) | |
4087 | gprintf(" %1m", conn->vulnerable2[pos]); | |
4088 | gprintf("\n", pos); | |
4089 | } | |
4090 | } | |
4091 | ||
4092 | ||
4093 | /* Test whether there is a trivial connection between str1 and str2 | |
4094 | * and if so return the connecting move in *move. By trivial | |
4095 | * connection we mean that they either have a common liberty or a | |
4096 | * common neighbor which can be tactically attacked. | |
4097 | */ | |
4098 | static int | |
4099 | trivial_connection(int str1, int str2, int *move) | |
4100 | { | |
4101 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
4102 | int save_count_variations = count_variations; | |
4103 | int adj, adjs[MAXCHAIN]; | |
4104 | int r; | |
4105 | int result = 0; | |
4106 | ||
4107 | if (have_common_lib(str1, str2, move)) | |
4108 | return WIN; | |
4109 | ||
4110 | adj = chainlinks(str1, adjs); | |
4111 | ||
4112 | /* We turn off the sgf traces here to avoid cluttering them up with | |
4113 | * tactical reading moves. | |
4114 | */ | |
4115 | sgf_dumptree = NULL; | |
4116 | count_variations = 0; | |
4117 | ||
4118 | for (r = 0; r < adj; r++) | |
4119 | if (adjacent_strings(adjs[r], str2) && attack(adjs[r], move) == WIN) { | |
4120 | result = WIN; | |
4121 | break; | |
4122 | } | |
4123 | ||
4124 | /* Turn the sgf traces back on. */ | |
4125 | sgf_dumptree = save_sgf_dumptree; | |
4126 | count_variations = save_count_variations; | |
4127 | ||
4128 | return result; | |
4129 | } | |
4130 | ||
4131 | ||
4132 | /* True if a move by color makes an opponent move at pos a self atari | |
4133 | * or possible to capture in a ladder. | |
4134 | */ | |
4135 | static int | |
4136 | does_secure_through_ladder(int color, int move, int pos) | |
4137 | { | |
4138 | int result = 0; | |
4139 | ||
4140 | if (trymove(move, color, NULL, NO_MOVE)) { | |
4141 | if (ladder_capturable(pos, OTHER_COLOR(color))) | |
4142 | result = 1; | |
4143 | popgo(); | |
4144 | } | |
4145 | ||
4146 | return result; | |
4147 | } | |
4148 | ||
4149 | /* Test whether the string str can be immediately taken off the board | |
4150 | * or captured in a ladder. If so the capturing move is returned in | |
4151 | * *move. | |
4152 | */ | |
4153 | static int | |
4154 | ladder_capture(int str, int *move) | |
4155 | { | |
4156 | int result; | |
4157 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
4158 | int save_count_variations = count_variations; | |
4159 | int liberties = countlib(str); | |
4160 | ||
4161 | /* We turn off the sgf traces here to avoid cluttering them up with | |
4162 | * tactical reading moves. | |
4163 | */ | |
4164 | sgf_dumptree = NULL; | |
4165 | count_variations = 0; | |
4166 | ||
4167 | if (liberties == 1) | |
4168 | result = attack(str, move); | |
4169 | else if (liberties == 2) | |
4170 | result = simple_ladder(str, move); | |
4171 | else | |
4172 | result = 0; | |
4173 | ||
4174 | /* Turn the sgf traces back on. */ | |
4175 | sgf_dumptree = save_sgf_dumptree; | |
4176 | count_variations = save_count_variations; | |
4177 | ||
4178 | return result; | |
4179 | } | |
4180 | ||
4181 | /* Test whether a move at pos by color can be captured in a ladder. */ | |
4182 | static int | |
4183 | ladder_capturable(int pos, int color) | |
4184 | { | |
4185 | int result = 0; | |
4186 | ||
4187 | if (trymove(pos, color, NULL, NO_MOVE)) { | |
4188 | int liberties = countlib(pos); | |
4189 | if (liberties == 1 && attack(pos, NULL) == WIN) | |
4190 | result = 1; | |
4191 | else if (liberties == 2 && simple_ladder(pos, NULL) == WIN) | |
4192 | result = 1; | |
4193 | popgo(); | |
4194 | } | |
4195 | else | |
4196 | result = 1; | |
4197 | ||
4198 | return result; | |
4199 | } | |
4200 | ||
4201 | ||
4202 | /* Test whether the string str with one liberty is stuck with at most | |
4203 | * one liberty. This function trivially returns false if the string | |
4204 | * has more than one liberty to start with. | |
4205 | */ | |
4206 | static int | |
4207 | no_escape_from_atari(int str) | |
4208 | { | |
4209 | int lib; | |
4210 | int adj[MAXCHAIN]; | |
4211 | ||
4212 | if (findlib(str, 1, &lib) > 1) | |
4213 | return 0; | |
4214 | ||
4215 | if (accuratelib(lib, board[str], 2, NULL) > 1) | |
4216 | return 0; | |
4217 | ||
4218 | /* FIXME: Should exclude snapback. */ | |
4219 | if (chainlinks2(str, adj, 1) > 0) | |
4220 | return 0; | |
4221 | ||
4222 | return 1; | |
4223 | } | |
4224 | ||
4225 | ||
4226 | /* Test whether the string str with one liberty is captured in a | |
4227 | * ladder. This function trivially returns false if the string has | |
4228 | * more than one liberty to start with, except for one special case. | |
4229 | * FIXME: Needs a simple_ladder_defense(). | |
4230 | */ | |
4231 | static int | |
4232 | no_escape_from_ladder(int str) | |
4233 | { | |
4234 | int result = 0; | |
4235 | SGFTree *save_sgf_dumptree = sgf_dumptree; | |
4236 | int save_count_variations = count_variations; | |
4237 | int adj[MAXCHAIN]; | |
4238 | int libs[2]; | |
4239 | ||
4240 | /* We turn off the sgf traces here to avoid cluttering them up with | |
4241 | * tactical reading moves. | |
4242 | */ | |
4243 | sgf_dumptree = NULL; | |
4244 | count_variations = 0; | |
4245 | ||
4246 | if (countlib(str) == 1 && find_defense(str, NULL) == 0) | |
4247 | result = 1; | |
4248 | ||
4249 | if (countlib(str) == 2 | |
4250 | && chainlinks2(str, adj, 1) == 0 | |
4251 | && findlib(str, 2, libs) == 2 | |
4252 | && approxlib(libs[0], board[str], 2, NULL) == 1 | |
4253 | && approxlib(libs[1], board[str], 2, NULL) == 1 | |
4254 | && ladder_capture(str, NULL) | |
4255 | && !find_defense(str, NULL)) | |
4256 | result = 1; | |
4257 | ||
4258 | ||
4259 | /* Turn the sgf traces back on. */ | |
4260 | sgf_dumptree = save_sgf_dumptree; | |
4261 | count_variations = save_count_variations; | |
4262 | ||
4263 | return result; | |
4264 | } | |
4265 | ||
4266 | /* We usually don't want to spend time with moves which are | |
4267 | * self-atari, unless the stone is involved in a ko. | |
4268 | */ | |
4269 | static int | |
4270 | check_self_atari(int pos, int color_to_move) | |
4271 | { | |
4272 | #if 1 | |
4273 | int lib; | |
4274 | #endif | |
4275 | ||
4276 | if (!is_self_atari(pos, color_to_move)) | |
4277 | return 1; | |
4278 | ||
4279 | if (is_ko(pos, color_to_move, NULL)) | |
4280 | return 1; | |
4281 | ||
4282 | #if 1 | |
4283 | /* FIXME: At some time I added this exceptional case but I can no | |
4284 | * longer see how it would be useful. It might still be, however, so | |
4285 | * I leave the code in for a while. /gf | |
4286 | * | |
4287 | * Code reactivated, see nando:31. /nn | |
4288 | * | |
4289 | * Added requirement that no additional stones are sacrificed in the | |
4290 | * self atari. /gf | |
4291 | * | |
4292 | * FIXME: Add a function in board.c to check how big the string | |
4293 | * becomes when playing a move and use for the isolated stone | |
4294 | * test below. | |
4295 | */ | |
4296 | if (approxlib(pos, color_to_move, 1, &lib) >= 1 | |
4297 | && approxlib(lib, OTHER_COLOR(color_to_move), 3, NULL) <= 2 | |
4298 | && ladder_capturable(lib, OTHER_COLOR(color_to_move))) { | |
4299 | int k; | |
4300 | for (k = 0; k < 4; k++) { | |
4301 | if (board[pos + delta[k]] == color_to_move) | |
4302 | break; | |
4303 | } | |
4304 | if (k == 4) | |
4305 | return 1; | |
4306 | } | |
4307 | #endif | |
4308 | ||
4309 | return 0; | |
4310 | } | |
4311 | ||
4312 | /* Check for overlap between (a1, a2) and (b1, b2). */ | |
4313 | static int | |
4314 | common_vulnerabilities(int a1, int a2, int b1, int b2, int color) | |
4315 | { | |
4316 | return (common_vulnerability(a1, b1, color) | |
4317 | || common_vulnerability(a1, b2, color) | |
4318 | || common_vulnerability(a2, b1, color) | |
4319 | || common_vulnerability(a2, b2, color)); | |
4320 | } | |
4321 | ||
4322 | /* Check if apos and bpos are the same or if they are both liberties | |
4323 | * of a string of the given color with at most three liberties. | |
4324 | */ | |
4325 | static int | |
4326 | common_vulnerability(int apos, int bpos, int color) | |
4327 | { | |
4328 | int k; | |
4329 | ||
4330 | if (apos == NO_MOVE || bpos == NO_MOVE) | |
4331 | return 0; | |
4332 | ||
4333 | if (apos == bpos) | |
4334 | return 1; | |
4335 | ||
4336 | for (k = 0; k < 4; k++) | |
4337 | if (board[apos + delta[k]] == color | |
4338 | && countlib(apos + delta[k]) <= 3 | |
4339 | && liberty_of_string(bpos, apos + delta[k])) | |
4340 | return 1; | |
4341 | ||
4342 | return 0; | |
4343 | } | |
4344 | ||
4345 | /* | |
4346 | * Local Variables: | |
4347 | * tab-width: 8 | |
4348 | * c-basic-offset: 2 | |
4349 | * End: | |
4350 | */ |