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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 <string.h> | |
29 | #include "liberty.h" | |
30 | #include "eyes.h" | |
31 | #include "gg_utils.h" | |
32 | ||
33 | #define MAXEYE 20 | |
34 | ||
35 | ||
36 | /* This structure is used in communication between read_eye() and | |
37 | * recognize_eye(). | |
38 | */ | |
39 | struct vital_points { | |
40 | int attacks[4 * MAXEYE]; | |
41 | int defenses[4 * MAXEYE]; | |
42 | int num_attacks; | |
43 | int num_defenses; | |
44 | }; | |
45 | ||
46 | ||
47 | static void | |
48 | compute_primary_domains(int color, int domain[BOARDMAX], | |
49 | int lively[BOARDMAX], | |
50 | int false_margins[BOARDMAX], | |
51 | int first_time); | |
52 | static void count_neighbours(struct eye_data eyedata[BOARDMAX]); | |
53 | static int is_lively(int owl_call, int pos); | |
54 | static int false_margin(int pos, int color, int lively[BOARDMAX]); | |
55 | static void originate_eye(int origin, int pos, | |
56 | int *esize, int *msize, | |
57 | struct eye_data eye[BOARDMAX]); | |
58 | static int read_eye(int pos, int *attack_point, int *defense_point, | |
59 | struct eyevalue *value, | |
60 | struct eye_data eye[BOARDMAX], | |
61 | struct half_eye_data heye[BOARDMAX], | |
62 | int add_moves); | |
63 | static int recognize_eye(int pos, int *attack_point, int *defense_point, | |
64 | struct eyevalue *value, | |
65 | struct eye_data eye[BOARDMAX], | |
66 | struct half_eye_data heye[BOARDMAX], | |
67 | struct vital_points *vp); | |
68 | static void guess_eye_space(int pos, int effective_eyesize, int margins, | |
69 | int bulk_score, struct eye_data eye[BOARDMAX], | |
70 | struct eyevalue *value, int *pessimistic_min); | |
71 | static void reset_map(int size); | |
72 | static void first_map(int *map_value); | |
73 | static int next_map(int *q, int map[MAXEYE]); | |
74 | static void print_eye(struct eye_data eye[BOARDMAX], | |
75 | struct half_eye_data heye[BOARDMAX], int pos); | |
76 | static void add_false_eye(int pos, struct eye_data eye[BOARDMAX], | |
77 | struct half_eye_data heye[BOARDMAX]); | |
78 | static float topological_eye(int pos, int color, | |
79 | struct eye_data my_eye[BOARDMAX], | |
80 | struct half_eye_data heye[BOARDMAX]); | |
81 | static float evaluate_diagonal_intersection(int m, int n, int color, | |
82 | int *attack_point, | |
83 | int *defense_point, | |
84 | struct eye_data my_eye[BOARDMAX]); | |
85 | ||
86 | ||
87 | /* These are used during the calculations of eye spaces. */ | |
88 | static int black_domain[BOARDMAX]; | |
89 | static int white_domain[BOARDMAX]; | |
90 | ||
91 | /* Used internally by mapping functions. */ | |
92 | static int map_size; | |
93 | static signed char used_index[MAXEYE]; | |
94 | ||
95 | ||
96 | /* | |
97 | * make_domains() is called from make_dragons() and from | |
98 | * owl_determine_life(). It marks the black and white domains | |
99 | * (eyeshape regions) and collects some statistics about each one. | |
100 | */ | |
101 | ||
102 | void | |
103 | make_domains(struct eye_data b_eye[BOARDMAX], | |
104 | struct eye_data w_eye[BOARDMAX], | |
105 | int owl_call) | |
106 | { | |
107 | int k; | |
108 | int pos; | |
109 | int lively[BOARDMAX]; | |
110 | int false_margins[BOARDMAX]; | |
111 | ||
112 | memset(black_domain, 0, sizeof(black_domain)); | |
113 | memset(white_domain, 0, sizeof(white_domain)); | |
114 | memset(false_margins, 0, sizeof(false_margins)); | |
115 | ||
116 | if (b_eye) | |
117 | memset(b_eye, 0, BOARDMAX * sizeof(b_eye[0])); | |
118 | if (w_eye) | |
119 | memset(w_eye, 0, BOARDMAX * sizeof(w_eye[0])); | |
120 | ||
121 | /* Initialize eye data and compute the lively array. */ | |
122 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
123 | if (ON_BOARD(pos)) | |
124 | lively[pos] = is_lively(owl_call, pos); | |
125 | ||
126 | /* Compute the domains of influence of each color. */ | |
127 | compute_primary_domains(BLACK, black_domain, lively, false_margins, 1); | |
128 | compute_primary_domains(WHITE, white_domain, lively, false_margins, 0); | |
129 | ||
130 | /* Now we fill out the arrays b_eye and w_eye with data describing | |
131 | * each eye shape. | |
132 | */ | |
133 | ||
134 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
135 | if (!ON_BOARD(pos)) | |
136 | continue; | |
137 | ||
138 | if (board[pos] == EMPTY || !lively[pos]) { | |
139 | if (black_domain[pos] == 0 && white_domain[pos] == 0) { | |
140 | if (w_eye) | |
141 | w_eye[pos].color = GRAY; | |
142 | if (b_eye) | |
143 | b_eye[pos].color = GRAY; | |
144 | } | |
145 | else if (black_domain[pos] == 1 && white_domain[pos] == 0 && b_eye) { | |
146 | b_eye[pos].color = BLACK; | |
147 | for (k = 0; k < 4; k++) { | |
148 | int apos = pos + delta[k]; | |
149 | if (ON_BOARD(apos) && white_domain[apos] && !black_domain[apos]) { | |
150 | b_eye[pos].marginal = 1; | |
151 | break; | |
152 | } | |
153 | } | |
154 | } | |
155 | else if (black_domain[pos] == 0 && white_domain[pos] == 1 && w_eye) { | |
156 | w_eye[pos].color = WHITE; | |
157 | for (k = 0; k < 4; k++) { | |
158 | int apos = pos + delta[k]; | |
159 | if (ON_BOARD(apos) && black_domain[apos] && !white_domain[apos]) { | |
160 | w_eye[pos].marginal = 1; | |
161 | break; | |
162 | } | |
163 | } | |
164 | } | |
165 | else if (black_domain[pos] == 1 && white_domain[pos] == 1) { | |
166 | if (b_eye) { | |
167 | for (k = 0; k < 4; k++) { | |
168 | int apos = pos + delta[k]; | |
169 | if (ON_BOARD(apos) && black_domain[apos] | |
170 | && !white_domain[apos]) { | |
171 | b_eye[pos].marginal = 1; | |
172 | b_eye[pos].color = BLACK; | |
173 | break; | |
174 | } | |
175 | } | |
176 | if (k == 4) | |
177 | b_eye[pos].color = GRAY; | |
178 | } | |
179 | ||
180 | if (w_eye) { | |
181 | for (k = 0; k < 4; k++) { | |
182 | int apos = pos + delta[k]; | |
183 | if (ON_BOARD(apos) && white_domain[apos] | |
184 | && !black_domain[apos]) { | |
185 | w_eye[pos].marginal = 1; | |
186 | w_eye[pos].color = WHITE; | |
187 | break; | |
188 | } | |
189 | } | |
190 | if (k == 4) | |
191 | w_eye[pos].color = GRAY; | |
192 | } | |
193 | } | |
194 | } | |
195 | } | |
196 | ||
197 | /* The eye spaces are all found. Now we need to find the origins. */ | |
198 | partition_eyespaces(b_eye, BLACK); | |
199 | partition_eyespaces(w_eye, WHITE); | |
200 | } | |
201 | ||
202 | /* Find connected eyespace components and compute relevant statistics. */ | |
203 | void | |
204 | partition_eyespaces(struct eye_data eye[BOARDMAX], int color) | |
205 | { | |
206 | int pos; | |
207 | ||
208 | if (!eye) | |
209 | return; | |
210 | ||
211 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
212 | if (ON_BOARD(pos)) | |
213 | eye[pos].origin = NO_MOVE; | |
214 | ||
215 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
216 | if (!ON_BOARD(pos)) | |
217 | continue; | |
218 | if (eye[pos].origin == NO_MOVE && eye[pos].color == color) { | |
219 | int esize = 0; | |
220 | int msize = 0; | |
221 | ||
222 | originate_eye(pos, pos, &esize, &msize, eye); | |
223 | eye[pos].esize = esize; | |
224 | eye[pos].msize = msize; | |
225 | } | |
226 | } | |
227 | ||
228 | /* Now we count the number of neighbors and marginal neighbors | |
229 | * of each vertex. | |
230 | */ | |
231 | count_neighbours(eye); | |
232 | } | |
233 | ||
234 | ||
235 | /* Compute the domains of influence of each color, used in determining | |
236 | * eye shapes. NOTE: the term influence as used here is distinct from the | |
237 | * influence in influence.c. | |
238 | * | |
239 | * For this algorithm the strings which are not lively are invisible. Ignoring | |
240 | * these, the algorithm assigns friendly influence to: | |
241 | * | |
242 | * (1) every vertex which is occupied by a (lively) friendly stone, | |
243 | * (2) every empty vertex adjoining a (lively) friendly stone, | |
244 | * (3) every empty vertex for which two adjoining vertices (not | |
245 | * on the first line) in the (usually 8) surrounding ones have friendly | |
246 | * influence, with two CAVEATS explained below. | |
247 | * | |
248 | * Thus in the following diagram, e would be assigned friendly influence | |
249 | * if a and b have friendly influence, or a and d. It is not sufficent | |
250 | * for b and d to have friendly influence, because they are not adjoining. | |
251 | * | |
252 | * uabc | |
253 | * def | |
254 | * ghi | |
255 | * | |
256 | * The constraint that the two adjoining vertices not lie on the first | |
257 | * line prevents influence from leaking under a stone on the third line. | |
258 | * | |
259 | * The first CAVEAT alluded to above is that even if a and b have friendly | |
260 | * influence, this does not cause e to have friendly influence if there | |
261 | * is a lively opponent stone at d. This constraint prevents | |
262 | * influence from leaking past knight's move extensions. | |
263 | * | |
264 | * The second CAVEAT is that even if a and b have friendly influence | |
265 | * this does not cause e to have influence if there are lively opponent | |
266 | * stones at u and at c. This prevents influence from leaking past | |
267 | * nikken tobis (two space jumps). | |
268 | * | |
269 | * The corner vertices are handled slightly different. | |
270 | * | |
271 | * +--- | |
272 | * |ab | |
273 | * |cd | |
274 | * | |
275 | * We get friendly influence at a if we have friendly influence | |
276 | * at b or c and no lively unfriendly stone at b, c or d. | |
277 | * | |
278 | */ | |
279 | ||
280 | #define sufficient_influence(pos, apos, bpos) \ | |
281 | (ON_BOARD(bpos) && influence[bpos] > threshold[pos] - influence[apos]) | |
282 | ||
283 | static void | |
284 | compute_primary_domains(int color, int domain[BOARDMAX], | |
285 | int lively[BOARDMAX], | |
286 | int false_margins[BOARDMAX], | |
287 | int first_time) | |
288 | { | |
289 | int other = OTHER_COLOR(color); | |
290 | int i, j, k; | |
291 | int pos, pos2; | |
292 | int own, enemy; | |
293 | signed char threshold[BOARDMAX]; | |
294 | signed char influence[BOARDMAX]; | |
295 | int list[BOARDMAX]; | |
296 | int size = 0, lastchange = 0; | |
297 | ||
298 | memset(threshold, 0, sizeof(threshold)); | |
299 | memset(influence, 0, sizeof(influence)); | |
300 | ||
301 | /* In the first pass we | |
302 | * 1. Give influence to lively own stones and their neighbors. | |
303 | * (Cases (1) and (2) above.) | |
304 | * 2. Fill influence[] and threshold[] arrays with initial values. | |
305 | */ | |
306 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
307 | if (!ON_BOARD(pos)) | |
308 | continue; | |
309 | ||
310 | if (lively[pos]) { | |
311 | if (board[pos] == color) { | |
312 | domain[pos] = 1; /* Case (1) above. */ | |
313 | influence[pos] = 1; | |
314 | } | |
315 | else | |
316 | influence[pos] = -1; | |
317 | continue; | |
318 | } | |
319 | ||
320 | own = enemy = 0; | |
321 | for (k = 0; k < 4; k++) { | |
322 | pos2 = pos + delta[k]; | |
323 | if (ON_BOARD(pos2) && lively[pos2]) { | |
324 | if (board[pos2] == color) | |
325 | own = 1; | |
326 | else | |
327 | enemy = 1; | |
328 | } | |
329 | } | |
330 | ||
331 | if (own) { | |
332 | /* To explain the asymmetry between the first time around | |
333 | * this loop and subsequent ones, a false margin is adjacent | |
334 | * to both B and W lively stones, so it's found on the first | |
335 | * pass through the loop. | |
336 | */ | |
337 | if (first_time) { | |
338 | if (board[pos] == EMPTY && (false_margin(pos, color, lively) | |
339 | || false_margin(pos, other, lively))) | |
340 | false_margins[pos] = 1; | |
341 | else { | |
342 | domain[pos] = 1; | |
343 | influence[pos] = 1; | |
344 | } | |
345 | } | |
346 | else if (board[pos] != EMPTY || !false_margins[pos]) { | |
347 | domain[pos] = 1; | |
348 | influence[pos] = 1; | |
349 | } | |
350 | } | |
351 | else | |
352 | list[size++] = pos; | |
353 | ||
354 | if (enemy) { | |
355 | threshold[pos] = 1; | |
356 | influence[pos]--; | |
357 | } | |
358 | else if (is_edge_vertex(pos)) | |
359 | influence[pos]--; | |
360 | } | |
361 | ||
362 | /* Now we loop over the board until no more vertices can be added to | |
363 | * the domain through case (3) above. | |
364 | */ | |
365 | if (size) { | |
366 | k = size; | |
367 | while (1) { | |
368 | if (!k) | |
369 | k = size; | |
370 | pos = list[--k]; | |
371 | ||
372 | /* Case (3) above. */ | |
373 | if (sufficient_influence(pos, SOUTH(pos), SE(pos)) | |
374 | || sufficient_influence(pos, SOUTH(pos), SW(pos)) | |
375 | || sufficient_influence(pos, EAST(pos), SE(pos)) | |
376 | || sufficient_influence(pos, EAST(pos), NE(pos)) | |
377 | || sufficient_influence(pos, WEST(pos), SW(pos)) | |
378 | || sufficient_influence(pos, WEST(pos), NW(pos)) | |
379 | || sufficient_influence(pos, NORTH(pos), NW(pos)) | |
380 | || sufficient_influence(pos, NORTH(pos), NE(pos))) { | |
381 | domain[pos] = 1; | |
382 | influence[pos]++; | |
383 | ||
384 | if (!--size) | |
385 | break; | |
386 | if (k < size) | |
387 | list[k] = list[size]; | |
388 | else | |
389 | k--; | |
390 | lastchange = k; | |
391 | } | |
392 | else if (k == lastchange) | |
393 | break; /* Looped the whole list and found nothing new */ | |
394 | } | |
395 | } | |
396 | ||
397 | if (0 && (debug & DEBUG_EYES)) { | |
398 | start_draw_board(); | |
399 | for (i = 0; i < board_size; i++) | |
400 | for (j = 0; j < board_size; j++) { | |
401 | draw_color_char(i, j, domain[POS(i, j)] ? '1' : '0', GG_COLOR_BLACK); | |
402 | } | |
403 | end_draw_board(); | |
404 | } | |
405 | } | |
406 | ||
407 | ||
408 | static void | |
409 | count_neighbours(struct eye_data eyedata[BOARDMAX]) | |
410 | { | |
411 | int pos; | |
412 | int k; | |
413 | ||
414 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
415 | if (!ON_BOARD(pos) || eyedata[pos].origin == NO_MOVE) | |
416 | continue; | |
417 | ||
418 | eyedata[pos].esize = eyedata[eyedata[pos].origin].esize; | |
419 | eyedata[pos].msize = eyedata[eyedata[pos].origin].msize; | |
420 | eyedata[pos].neighbors = 0; | |
421 | eyedata[pos].marginal_neighbors = 0; | |
422 | ||
423 | for (k = 0; k < 4; k++) { | |
424 | int pos2 = pos + delta[k]; | |
425 | if (ON_BOARD(pos2) && eyedata[pos2].origin == eyedata[pos].origin) { | |
426 | eyedata[pos].neighbors++; | |
427 | if (eyedata[pos2].marginal) | |
428 | eyedata[pos].marginal_neighbors++; | |
429 | } | |
430 | } | |
431 | } | |
432 | } | |
433 | ||
434 | ||
435 | static int | |
436 | is_lively(int owl_call, int pos) | |
437 | { | |
438 | if (board[pos] == EMPTY) | |
439 | return 0; | |
440 | ||
441 | if (owl_call) | |
442 | return owl_lively(pos); | |
443 | else | |
444 | return (!worm[pos].inessential | |
445 | && (worm[pos].attack_codes[0] == 0 | |
446 | || worm[pos].defense_codes[0] != 0)); | |
447 | } | |
448 | ||
449 | ||
450 | /* In the following situation, we do not wish the vertex at 'a' | |
451 | * included in the O eye space: | |
452 | * | |
453 | * OOOOXX | |
454 | * OXaX.. | |
455 | * ------ | |
456 | * | |
457 | * This eyespace should parse as (X), not (X!). Thus the vertex | |
458 | * should not be included in the eyespace if it is adjacent to | |
459 | * an X stone which is alive, yet X cannot play safely at a. | |
460 | * The function returns 1 if this situation is found at | |
461 | * (pos) for color O. | |
462 | * | |
463 | * The condition above is true, curiously enough, also for the | |
464 | * following case: | |
465 | * A group has two eyes, one of size 1 and one which is critical 1/2. | |
466 | * It also has to have less than 4 external liberties, since the | |
467 | * reading has to be able to capture the group tactically. In that | |
468 | * case, the eye of size one will be treated as a false marginal. | |
469 | * Thus we have to exclude this case, which is done by requiring (pos) | |
470 | * to be adjacent to both white and black stones. Since this test is | |
471 | * least expensive, we start with it. | |
472 | * | |
473 | * As a second optimization we require that one of the other colored | |
474 | * neighbors is not lively. This should cut down on the number of | |
475 | * calls to attack() and safe_move(). | |
476 | */ | |
477 | ||
478 | static int | |
479 | false_margin(int pos, int color, int lively[BOARDMAX]) | |
480 | { | |
481 | int other = OTHER_COLOR(color); | |
482 | int neighbors = 0; | |
483 | int k; | |
484 | int all_lively; | |
485 | int potential_false_margin; | |
486 | ||
487 | /* Require neighbors of both colors. */ | |
488 | for (k = 0; k < 4; k++) | |
489 | if (ON_BOARD(pos + delta[k])) | |
490 | neighbors |= board[pos + delta[k]]; | |
491 | ||
492 | if (neighbors != (WHITE | BLACK)) | |
493 | return 0; | |
494 | ||
495 | /* At least one opponent neighbor should be not lively. */ | |
496 | all_lively = 1; | |
497 | for (k = 0; k < 4; k++) | |
498 | if (board[pos + delta[k]] == other && !lively[pos + delta[k]]) | |
499 | all_lively = 0; | |
500 | ||
501 | if (all_lively) | |
502 | return 0; | |
503 | ||
504 | potential_false_margin = 0; | |
505 | for (k = 0; k < 4; k++) { | |
506 | int apos = pos + delta[k]; | |
507 | if (board[apos] != other || !lively[apos]) | |
508 | continue; | |
509 | ||
510 | if (stackp == 0 && worm[apos].attack_codes[0] == 0) | |
511 | potential_false_margin = 1; | |
512 | ||
513 | if (stackp > 0 && !attack(apos, NULL)) | |
514 | potential_false_margin = 1; | |
515 | } | |
516 | ||
517 | if (potential_false_margin && safe_move(pos, other) == 0) { | |
518 | DEBUG(DEBUG_EYES, "False margin for %C at %1m.\n", color, pos); | |
519 | return 1; | |
520 | } | |
521 | ||
522 | return 0; | |
523 | } | |
524 | ||
525 | ||
526 | /* | |
527 | * originate_eye(pos, pos, *esize, *msize, eye) creates an eyeshape | |
528 | * with origin pos. esize and msize return the size and the number of | |
529 | * marginal vertices. The repeated variables (pos) are due to the | |
530 | * recursive definition of the function. | |
531 | */ | |
532 | static void | |
533 | originate_eye(int origin, int pos, | |
534 | int *esize, int *msize, | |
535 | struct eye_data eye[BOARDMAX]) | |
536 | { | |
537 | int k; | |
538 | ASSERT_ON_BOARD1(origin); | |
539 | ASSERT_ON_BOARD1(pos); | |
540 | gg_assert(esize != NULL); | |
541 | gg_assert(msize != NULL); | |
542 | ||
543 | eye[pos].origin = origin; | |
544 | (*esize)++; | |
545 | if (eye[pos].marginal) | |
546 | (*msize)++; | |
547 | ||
548 | for (k = 0; k < 4; k++) { | |
549 | int pos2 = pos + delta[k]; | |
550 | if (ON_BOARD(pos2) | |
551 | && eye[pos2].color == eye[pos].color | |
552 | && eye[pos2].origin == NO_MOVE | |
553 | && (!eye[pos2].marginal || !eye[pos].marginal)) | |
554 | originate_eye(origin, pos2, esize, msize, eye); | |
555 | } | |
556 | } | |
557 | ||
558 | ||
559 | /* | |
560 | * propagate_eye(origin) copies the data at the (origin) to the | |
561 | * rest of the eye (invariant fields only). | |
562 | */ | |
563 | ||
564 | void | |
565 | propagate_eye(int origin, struct eye_data eye[BOARDMAX]) | |
566 | { | |
567 | int pos; | |
568 | ||
569 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
570 | if (ON_BOARD(pos) && eye[pos].origin == origin) { | |
571 | eye[pos].color = eye[origin].color; | |
572 | eye[pos].esize = eye[origin].esize; | |
573 | eye[pos].msize = eye[origin].msize; | |
574 | eye[pos].origin = eye[origin].origin; | |
575 | eye[pos].value = eye[origin].value; | |
576 | } | |
577 | } | |
578 | ||
579 | ||
580 | /* Find the dragon or dragons surrounding an eye space. Up to | |
581 | * max_dragons dragons adjacent to the eye space are added to | |
582 | * the dragon array, and the number of dragons found is returned. | |
583 | */ | |
584 | ||
585 | int | |
586 | find_eye_dragons(int origin, struct eye_data eye[BOARDMAX], int eye_color, | |
587 | int dragons[], int max_dragons) | |
588 | { | |
589 | int mx[BOARDMAX]; | |
590 | int num_dragons = 0; | |
591 | int pos; | |
592 | ||
593 | memset(mx, 0, sizeof(mx)); | |
594 | DEBUG(DEBUG_MISCELLANEOUS, "find_eye_dragons: %1m %C\n", origin, eye_color); | |
595 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
596 | if (board[pos] == eye_color | |
597 | && mx[dragon[pos].origin] == 0 | |
598 | && ((ON_BOARD(SOUTH(pos)) | |
599 | && eye[SOUTH(pos)].origin == origin | |
600 | && !eye[SOUTH(pos)].marginal) | |
601 | || (ON_BOARD(WEST(pos)) | |
602 | && eye[WEST(pos)].origin == origin | |
603 | && !eye[WEST(pos)].marginal) | |
604 | || (ON_BOARD(NORTH(pos)) | |
605 | && eye[NORTH(pos)].origin == origin | |
606 | && !eye[NORTH(pos)].marginal) | |
607 | || (ON_BOARD(EAST(pos)) | |
608 | && eye[EAST(pos)].origin == origin | |
609 | && !eye[EAST(pos)].marginal))) { | |
610 | DEBUG(DEBUG_MISCELLANEOUS, | |
611 | " dragon: %1m %1m\n", pos, dragon[pos].origin); | |
612 | mx[dragon[pos].origin] = 1; | |
613 | if (dragons != NULL && num_dragons < max_dragons) | |
614 | dragons[num_dragons] = dragon[pos].origin; | |
615 | num_dragons++; | |
616 | } | |
617 | } | |
618 | ||
619 | return num_dragons; | |
620 | } | |
621 | ||
622 | /* Print debugging data for the eyeshape at (i,j). Useful with GDB. | |
623 | */ | |
624 | ||
625 | static void | |
626 | print_eye(struct eye_data eye[BOARDMAX], struct half_eye_data heye[BOARDMAX], | |
627 | int pos) | |
628 | { | |
629 | int m, n; | |
630 | int pos2; | |
631 | int mini, maxi; | |
632 | int minj, maxj; | |
633 | int origin = eye[pos].origin; | |
634 | ||
635 | gprintf("Eyespace at %1m: color=%C, esize=%d, msize=%d\n", | |
636 | pos, eye[pos].color, eye[pos].esize, eye[pos].msize); | |
637 | ||
638 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) { | |
639 | if (!ON_BOARD(pos2)) | |
640 | continue; | |
641 | ||
642 | if (eye[pos2].origin != pos) | |
643 | continue; | |
644 | ||
645 | if (eye[pos2].marginal && IS_STONE(board[pos2])) | |
646 | gprintf("%1m (X!)\n", pos2); | |
647 | else if (is_halfeye(heye, pos2) && IS_STONE(board[pos2])) { | |
648 | if (heye[pos2].value == 3.0) | |
649 | gprintf("%1m (XH)\n", pos2); | |
650 | else | |
651 | gprintf("%1m (XH) (topological eye value = %f)\n", pos2, | |
652 | heye[pos2].value); | |
653 | } | |
654 | else if (!eye[pos2].marginal && IS_STONE(board[pos2])) | |
655 | gprintf("%1m (X)\n", pos2); | |
656 | else if (eye[pos2].marginal && board[pos2] == EMPTY) | |
657 | gprintf("%1m (!)\n", pos2); | |
658 | else if (is_halfeye(heye, pos2) && board[pos2] == EMPTY) { | |
659 | if (heye[pos2].value == 3.0) | |
660 | gprintf("%1m (H)\n", pos2); | |
661 | else | |
662 | gprintf("%1m (H) (topological eye value = %f)\n", pos2, | |
663 | heye[pos2].value); | |
664 | } | |
665 | else | |
666 | gprintf("%1m\n", pos2); | |
667 | } | |
668 | gprintf("\n"); | |
669 | ||
670 | /* Determine the size of the eye. */ | |
671 | mini = board_size; | |
672 | maxi = -1; | |
673 | minj = board_size; | |
674 | maxj = -1; | |
675 | for (m = 0; m < board_size; m++) | |
676 | for (n = 0; n < board_size; n++) { | |
677 | if (eye[POS(m, n)].origin != origin) | |
678 | continue; | |
679 | ||
680 | if (m < mini) mini = m; | |
681 | if (m > maxi) maxi = m; | |
682 | if (n < minj) minj = n; | |
683 | if (n > maxj) maxj = n; | |
684 | } | |
685 | ||
686 | /* Prints the eye shape. A half eye is shown by h, if empty or H, if an | |
687 | * enemy is present. Note that each half eye has a marginal point which is | |
688 | * not printed, so the representation here may have less points than the | |
689 | * matching eye pattern in eyes.db. Printing a marginal for the half eye | |
690 | * would be nice, but difficult to implement. | |
691 | */ | |
692 | for (m = mini; m <= maxi; m++) { | |
693 | gprintf(""); /* Get the indentation right. */ | |
694 | for (n = minj; n <= maxj; n++) { | |
695 | int pos2 = POS(m, n); | |
696 | if (eye[pos2].origin == origin) { | |
697 | if (board[pos2] == EMPTY) { | |
698 | if (eye[pos2].marginal) | |
699 | gprintf("%o!"); | |
700 | else if (is_halfeye(heye, pos2)) | |
701 | gprintf("%oh"); | |
702 | else | |
703 | gprintf("%o."); | |
704 | } | |
705 | else if (is_halfeye(heye, pos2)) | |
706 | gprintf("%oH"); | |
707 | else | |
708 | gprintf("%oX"); | |
709 | } | |
710 | else | |
711 | gprintf("%o "); | |
712 | } | |
713 | gprintf("\n"); | |
714 | } | |
715 | } | |
716 | ||
717 | ||
718 | /* | |
719 | * Given an eyespace with origin (pos), this function computes the | |
720 | * minimum and maximum numbers of eyes the space can yield. If max and | |
721 | * min are different, then vital points of attack and defense are also | |
722 | * generated. | |
723 | * | |
724 | * If add_moves == 1, this function may add a move_reason for (color) at | |
725 | * a vital point which is found by the function. If add_moves == 0, | |
726 | * set color == EMPTY. | |
727 | */ | |
728 | ||
729 | void | |
730 | compute_eyes(int pos, struct eyevalue *value, | |
731 | int *attack_point, int *defense_point, | |
732 | struct eye_data eye[BOARDMAX], | |
733 | struct half_eye_data heye[BOARDMAX], int add_moves) | |
734 | { | |
735 | if (attack_point) | |
736 | *attack_point = NO_MOVE; | |
737 | if (defense_point) | |
738 | *defense_point = NO_MOVE; | |
739 | ||
740 | if (debug & DEBUG_EYES) { | |
741 | print_eye(eye, heye, pos); | |
742 | DEBUG(DEBUG_EYES, "\n"); | |
743 | } | |
744 | ||
745 | /* Look up the eye space in the graphs database. */ | |
746 | if (read_eye(pos, attack_point, defense_point, value, eye, heye, add_moves)) | |
747 | return; | |
748 | ||
749 | /* Ideally any eye space that hasn't been matched yet should be two | |
750 | * secure eyes. Until the database becomes more complete we have | |
751 | * some additional heuristics to guess the values of unknown | |
752 | * eyespaces. | |
753 | */ | |
754 | if (eye[pos].esize - 2*eye[pos].msize > 3) | |
755 | set_eyevalue(value, 2, 2, 2, 2); | |
756 | else if (eye[pos].esize - 2*eye[pos].msize > 0) | |
757 | set_eyevalue(value, 1, 1, 1, 1); | |
758 | else | |
759 | set_eyevalue(value, 0, 0, 0, 0); | |
760 | } | |
761 | ||
762 | ||
763 | /* | |
764 | * This function works like compute_eyes(), except that it also gives | |
765 | * a pessimistic view of the chances to make eyes. Since it is intended | |
766 | * to be used from the owl code, the option to add move reasons has | |
767 | * been removed. | |
768 | */ | |
769 | void | |
770 | compute_eyes_pessimistic(int pos, struct eyevalue *value, | |
771 | int *pessimistic_min, | |
772 | int *attack_point, int *defense_point, | |
773 | struct eye_data eye[BOARDMAX], | |
774 | struct half_eye_data heye[BOARDMAX]) | |
775 | { | |
776 | static int bulk_coefficients[5] = {-1, -1, 1, 4, 12}; | |
777 | ||
778 | int pos2; | |
779 | int margins = 0; | |
780 | int halfeyes = 0; | |
781 | int margins_adjacent_to_margin = 0; | |
782 | int effective_eyesize; | |
783 | int bulk_score = 0; | |
784 | signed char chainlinks[BOARDMAX]; | |
785 | ||
786 | /* Stones inside eyespace which do not coincide with a false eye or | |
787 | * a halfeye. | |
788 | */ | |
789 | int interior_stones = 0; | |
790 | ||
791 | memset(chainlinks, 0, BOARDMAX); | |
792 | ||
793 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) { | |
794 | int k; | |
795 | ||
796 | if (!ON_BOARD(pos2) || eye[pos2].origin != pos) | |
797 | continue; | |
798 | ||
799 | if (eye[pos2].marginal || is_halfeye(heye, pos2)) { | |
800 | margins++; | |
801 | if (eye[pos2].marginal && eye[pos2].marginal_neighbors > 0) | |
802 | margins_adjacent_to_margin++; | |
803 | if (is_halfeye(heye, pos2)) | |
804 | halfeyes++; | |
805 | } | |
806 | else if (IS_STONE(board[pos2])) | |
807 | interior_stones++; | |
808 | ||
809 | bulk_score += bulk_coefficients[(int) eye[pos2].neighbors]; | |
810 | ||
811 | for (k = 0; k < 4; k++) { | |
812 | int neighbor = pos2 + delta[k]; | |
813 | ||
814 | if (board[neighbor] == eye[pos].color) { | |
815 | if (!chainlinks[neighbor]) { | |
816 | bulk_score += 4; | |
817 | mark_string(neighbor, chainlinks, 1); | |
818 | } | |
819 | } | |
820 | else if (!ON_BOARD(neighbor)) | |
821 | bulk_score += 2; | |
822 | } | |
823 | } | |
824 | ||
825 | /* This is a measure based on the simplified assumption that both | |
826 | * players only cares about playing the marginal eye spaces. It is | |
827 | * used later to guess the eye value for unidentified eye shapes. | |
828 | */ | |
829 | effective_eyesize = (eye[pos].esize + halfeyes - 2*margins | |
830 | - margins_adjacent_to_margin); | |
831 | ||
832 | if (attack_point) | |
833 | *attack_point = NO_MOVE; | |
834 | if (defense_point) | |
835 | *defense_point = NO_MOVE; | |
836 | ||
837 | if (debug & DEBUG_EYES) { | |
838 | print_eye(eye, heye, pos); | |
839 | DEBUG(DEBUG_EYES, "\n"); | |
840 | } | |
841 | ||
842 | /* Look up the eye space in the graphs database. */ | |
843 | if (read_eye(pos, attack_point, defense_point, value, | |
844 | eye, heye, 0)) { | |
845 | *pessimistic_min = min_eyes(value) - margins; | |
846 | ||
847 | /* A single point eye which is part of a ko can't be trusted. */ | |
848 | if (eye[pos].esize == 1 | |
849 | && is_ko(pos, OTHER_COLOR(eye[pos].color), NULL)) | |
850 | *pessimistic_min = 0; | |
851 | ||
852 | DEBUG(DEBUG_EYES, " graph matching - %s, pessimistic_min=%d\n", | |
853 | eyevalue_to_string(value), *pessimistic_min); | |
854 | } | |
855 | ||
856 | /* Ideally any eye space that hasn't been matched yet should be two | |
857 | * secure eyes. Until the database becomes more complete we have | |
858 | * some additional heuristics to guess the values of unknown | |
859 | * eyespaces. | |
860 | */ | |
861 | else { | |
862 | guess_eye_space(pos, effective_eyesize, margins, bulk_score, eye, | |
863 | value, pessimistic_min); | |
864 | DEBUG(DEBUG_EYES, " guess_eye - %s, pessimistic_min=%d\n", | |
865 | eyevalue_to_string(value), *pessimistic_min); | |
866 | } | |
867 | ||
868 | if (*pessimistic_min < 0) { | |
869 | *pessimistic_min = 0; | |
870 | DEBUG(DEBUG_EYES, " pessimistic min revised to 0\n"); | |
871 | } | |
872 | ||
873 | /* An eyespace with at least two interior stones is assumed to be | |
874 | * worth at least one eye, regardless of previous considerations. | |
875 | */ | |
876 | if (*pessimistic_min < 1 && interior_stones >= 2) { | |
877 | *pessimistic_min = 1; | |
878 | DEBUG(DEBUG_EYES, " pessimistic min revised to 1 (interior stones)\n"); | |
879 | } | |
880 | ||
881 | if (attack_point | |
882 | && *attack_point == NO_MOVE | |
883 | && max_eyes(value) != *pessimistic_min) { | |
884 | /* Find one marginal vertex and set as attack and defense point. | |
885 | * | |
886 | * We make some effort to find the best marginal vertex by giving | |
887 | * priority to ones with more than one neighbor in the eyespace. | |
888 | * We prefer non-halfeye margins and ones which are not self-atari | |
889 | * for the opponent. Margins not on the edge are also favored. | |
890 | */ | |
891 | int best_attack_point = NO_MOVE; | |
892 | int best_defense_point = NO_MOVE; | |
893 | float score = 0.0; | |
894 | ||
895 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) { | |
896 | if (ON_BOARD(pos2) && eye[pos2].origin == pos) { | |
897 | float this_score = 0.0; | |
898 | int this_attack_point = NO_MOVE; | |
899 | int this_defense_point = NO_MOVE; | |
900 | if (eye[pos2].marginal && board[pos2] == EMPTY) { | |
901 | this_score = eye[pos2].neighbors; | |
902 | this_attack_point = pos2; | |
903 | this_defense_point = pos2; | |
904 | ||
905 | if (is_self_atari(pos2, OTHER_COLOR(eye[pos].color))) | |
906 | this_score -= 0.5; | |
907 | ||
908 | if (is_edge_vertex(pos2)) | |
909 | this_score -= 0.1; | |
910 | } | |
911 | else if (is_halfeye(heye, pos2)) { | |
912 | this_score = 0.75; | |
913 | this_defense_point = heye[pos2].defense_point[0]; | |
914 | this_attack_point = heye[pos2].attack_point[0]; | |
915 | } | |
916 | else | |
917 | continue; | |
918 | ||
919 | if (gg_normalize_float2int(this_score, 0.01) | |
920 | > gg_normalize_float2int(score, 0.01)) { | |
921 | best_attack_point = this_attack_point; | |
922 | best_defense_point = this_defense_point; | |
923 | score = this_score; | |
924 | } | |
925 | } | |
926 | } | |
927 | ||
928 | if (score > 0.0) { | |
929 | if (defense_point) | |
930 | *defense_point = best_defense_point; | |
931 | if (attack_point) | |
932 | *attack_point = best_attack_point; | |
933 | } | |
934 | } | |
935 | ||
936 | if (defense_point && *defense_point != NO_MOVE) { | |
937 | ASSERT_ON_BOARD1(*defense_point); | |
938 | } | |
939 | if (attack_point && *attack_point != NO_MOVE) { | |
940 | ASSERT_ON_BOARD1(*attack_point); | |
941 | } | |
942 | } | |
943 | ||
944 | ||
945 | static void | |
946 | guess_eye_space(int pos, int effective_eyesize, int margins, | |
947 | int bulk_score, struct eye_data eye[BOARDMAX], | |
948 | struct eyevalue *value, int *pessimistic_min) | |
949 | { | |
950 | if (effective_eyesize > 3) { | |
951 | set_eyevalue(value, 2, 2, 2, 2); | |
952 | *pessimistic_min = 1; | |
953 | ||
954 | if ((margins == 0 && effective_eyesize > 7) | |
955 | || (margins > 0 && effective_eyesize > 9)) { | |
956 | int eyes = 2 + (effective_eyesize - 2 * (margins > 0) - 8) / 2; | |
957 | int threshold = (4 * (eye[pos].esize - 2) | |
958 | + (effective_eyesize - 8) * (effective_eyesize - 9)); | |
959 | ||
960 | DEBUG(DEBUG_EYES, "size: %d(%d), threshold: %d, bulk score: %d\n", | |
961 | eye[pos].esize, effective_eyesize, threshold, bulk_score); | |
962 | ||
963 | if (bulk_score > threshold && effective_eyesize < 15) | |
964 | eyes = gg_max(2, eyes - ((bulk_score - threshold) / eye[pos].esize)); | |
965 | ||
966 | if (bulk_score < threshold + eye[pos].esize || effective_eyesize >= 15) | |
967 | *pessimistic_min = eyes; | |
968 | ||
969 | set_eyevalue(value, eyes, eyes, eyes, eyes); | |
970 | } | |
971 | } | |
972 | else if (effective_eyesize > 0) { | |
973 | set_eyevalue(value, 1, 1, 1, 1); | |
974 | if (margins > 0) | |
975 | *pessimistic_min = 0; | |
976 | else | |
977 | *pessimistic_min = 1; | |
978 | } | |
979 | else { | |
980 | if (eye[pos].esize - margins > 2) | |
981 | set_eyevalue(value, 0, 0, 1, 1); | |
982 | else | |
983 | set_eyevalue(value, 0, 0, 0, 0); | |
984 | *pessimistic_min = 0; | |
985 | } | |
986 | } | |
987 | ||
988 | ||
989 | /* This function does some minor reading to improve the results of | |
990 | * recognize_eye(). Currently, it has two duties. One is to read | |
991 | * positions like this: | |
992 | * | |
993 | * .XXXX| with half eye with proper eye | |
994 | * XXOOO| | |
995 | * XO.O.| . (1 eye) . (2 eyes) | |
996 | * XXOa.| !.. .* | |
997 | * -----+ | |
998 | * | |
999 | * recognize_eye() sees the eyespace of the white dragon as shown | |
1000 | * (there's a half eye at a and it is considered the same as '!.' by | |
1001 | * the optics code). Normally, that eye shape gives only one secure | |
1002 | * eye, and owl thinks that the white dragon is dead unconditionally. | |
1003 | * This function tries to turn such ko-dependent half eyes into proper | |
1004 | * eyes and chooses the best alternative. Note that we don't have any | |
1005 | * attack/defense codes here, since owl will determine them itself. | |
1006 | * | |
1007 | * Another one is related to some cases when replacing half eyes with | |
1008 | * '!.' doesn't work. E.g. consider this eye (optics:328): | |
1009 | * | |
1010 | * XXXOO eye graph is 310: | |
1011 | * X..X. | |
1012 | * XOXX. !.! (second '!' is due to the halfeye) | |
1013 | * OXO.. | |
1014 | * O.O.. | |
1015 | * | |
1016 | * When this function detects such a half eye that can be attacked | |
1017 | * and/or defended inside its eyespace, it tries to turn it into a | |
1018 | * proper eye and see what happens. In case it gives an improvement | |
1019 | * for attacker and/or defender, the function keeps new result but | |
1020 | * only if new vital points are also vital points for the half eye. | |
1021 | * The heuristics used here might need improvements since they are | |
1022 | * based on a single game position. | |
1023 | * | |
1024 | * If add_moves != 0, this function may add move reasons for (color) | |
1025 | * at the vital points which are found by recognize_eye(). If add_moves | |
1026 | * == 0, set color to be EMPTY. | |
1027 | */ | |
1028 | static int | |
1029 | read_eye(int pos, int *attack_point, int *defense_point, | |
1030 | struct eyevalue *value, struct eye_data eye[BOARDMAX], | |
1031 | struct half_eye_data heye[BOARDMAX], | |
1032 | int add_moves) | |
1033 | { | |
1034 | int eye_color; | |
1035 | int k; | |
1036 | int pos2; | |
1037 | int combination_halfeye = NO_MOVE; | |
1038 | int combination_attack = NO_MOVE; | |
1039 | int combination_defense = NO_MOVE; | |
1040 | int num_ko_halfeyes = 0; | |
1041 | int ko_halfeye = NO_MOVE; | |
1042 | struct vital_points vp; | |
1043 | struct vital_points ko_vp; | |
1044 | struct vital_points *best_vp = &vp; | |
1045 | ||
1046 | eye_color = recognize_eye(pos, attack_point, defense_point, value, | |
1047 | eye, heye, &vp); | |
1048 | if (!eye_color) | |
1049 | return 0; | |
1050 | ||
1051 | /* Find ko half eyes and "combination" half eyes if any. */ | |
1052 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) { | |
1053 | if (ON_BOARD(pos2) | |
1054 | && eye[pos2].origin == pos | |
1055 | && heye[pos2].type == HALF_EYE) { | |
1056 | if (combination_halfeye == NO_MOVE) { | |
1057 | int apos = NO_MOVE; | |
1058 | int dpos = NO_MOVE; | |
1059 | ||
1060 | for (k = 0; k < heye[pos2].num_attacks; k++) { | |
1061 | if (eye[heye[pos2].attack_point[k]].origin == pos) { | |
1062 | apos = heye[pos2].attack_point[k]; | |
1063 | break; | |
1064 | } | |
1065 | } | |
1066 | ||
1067 | for (k = 0; k < heye[pos2].num_defenses; k++) { | |
1068 | if (eye[heye[pos2].defense_point[k]].origin == pos) { | |
1069 | dpos = heye[pos2].defense_point[k]; | |
1070 | break; | |
1071 | } | |
1072 | } | |
1073 | ||
1074 | if (apos || dpos) { | |
1075 | combination_halfeye = pos2; | |
1076 | combination_attack = apos; | |
1077 | combination_defense = dpos; | |
1078 | } | |
1079 | } | |
1080 | ||
1081 | if (heye[pos2].value < 3.0) { | |
1082 | num_ko_halfeyes++; | |
1083 | ko_halfeye = pos2; | |
1084 | } | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | /* In case we have a "combination" half eye, turn it into a proper eye | |
1089 | * vertex for a while and see what happens. | |
1090 | */ | |
1091 | if (combination_halfeye != NO_MOVE) { | |
1092 | int result; | |
1093 | int apos = NO_MOVE; | |
1094 | int dpos = NO_MOVE; | |
1095 | struct eyevalue combination_value; | |
1096 | struct vital_points combination_vp; | |
1097 | ||
1098 | heye[combination_halfeye].type = 0; | |
1099 | result = recognize_eye(pos, &apos, &dpos, &combination_value, eye, | |
1100 | heye, &combination_vp); | |
1101 | heye[combination_halfeye].type = HALF_EYE; | |
1102 | ||
1103 | if (result) { | |
1104 | if (combination_attack | |
1105 | && min_eyes(value) > min_eyes(&combination_value)) { | |
1106 | /* FIXME: I'm not sure we can ever get here. */ | |
1107 | for (k = 0; k < combination_vp.num_attacks; k++) { | |
1108 | if (combination_vp.attacks[k] == combination_attack) { | |
1109 | value->a = combination_value.a; | |
1110 | value->b = combination_value.b; | |
1111 | *attack_point = apos; | |
1112 | best_vp->num_attacks = 1; | |
1113 | best_vp->attacks[0] = combination_attack; | |
1114 | break; | |
1115 | } | |
1116 | } | |
1117 | } | |
1118 | ||
1119 | if (combination_defense | |
1120 | && max_eyes(value) < max_eyes(&combination_value)) { | |
1121 | /* Turning the half eye into a proper eye gives an improvement. | |
1122 | * However, we can only accept this result if there is a vital | |
1123 | * point that defends both the half eye and the whole eyespace. | |
1124 | */ | |
1125 | for (k = 0; k < combination_vp.num_defenses; k++) { | |
1126 | if (combination_vp.defenses[k] == combination_defense) { | |
1127 | value->c = combination_value.c; | |
1128 | value->d = combination_value.d; | |
1129 | *defense_point = dpos; | |
1130 | best_vp->num_defenses = 1; | |
1131 | best_vp->defenses[0] = combination_defense; | |
1132 | break; | |
1133 | } | |
1134 | } | |
1135 | } | |
1136 | ||
1137 | if (min_eyes(value) != max_eyes(value)) { | |
1138 | ASSERT1(combination_attack || combination_defense, combination_halfeye); | |
1139 | if (*attack_point == NO_MOVE) { | |
1140 | *attack_point = combination_attack; | |
1141 | if (*attack_point == NO_MOVE) | |
1142 | *attack_point = combination_defense; | |
1143 | } | |
1144 | ||
1145 | if (*defense_point == NO_MOVE) { | |
1146 | *defense_point = combination_defense; | |
1147 | if (*defense_point == NO_MOVE) | |
1148 | *defense_point = combination_defense; | |
1149 | } | |
1150 | } | |
1151 | } | |
1152 | } | |
1153 | ||
1154 | /* The same with ko half eye (we cannot win two kos at once, therefore we | |
1155 | * give up if there is more than one ko half eye). | |
1156 | */ | |
1157 | if (num_ko_halfeyes == 1) { | |
1158 | int result; | |
1159 | int apos = NO_MOVE; | |
1160 | int dpos = NO_MOVE; | |
1161 | struct eyevalue ko_value; | |
1162 | ||
1163 | heye[ko_halfeye].type = 0; | |
1164 | result = recognize_eye(pos, &apos, &dpos, &ko_value, eye, | |
1165 | heye, &ko_vp); | |
1166 | heye[ko_halfeye].type = HALF_EYE; | |
1167 | ||
1168 | if (result && max_eyes(value) < max_eyes(&ko_value)) { | |
1169 | /* It is worthy to win the ko. */ | |
1170 | *value = ko_value; | |
1171 | *attack_point = apos; | |
1172 | *defense_point = dpos; | |
1173 | best_vp = &ko_vp; | |
1174 | } | |
1175 | } | |
1176 | ||
1177 | if (add_moves) { | |
1178 | struct vital_eye_points *vital; | |
1179 | if (eye_color == WHITE) | |
1180 | vital = white_vital_points; | |
1181 | else | |
1182 | vital = black_vital_points; | |
1183 | for (k = 0; k < best_vp->num_defenses && k < MAX_EYE_ATTACKS; k++) | |
1184 | vital[pos].defense_points[k] = best_vp->defenses[k]; | |
1185 | for (k = 0; k < best_vp->num_attacks && k < MAX_EYE_ATTACKS; k++) | |
1186 | vital[pos].attack_points[k] = best_vp->attacks[k]; | |
1187 | } | |
1188 | ||
1189 | return 1; | |
1190 | } | |
1191 | ||
1192 | ||
1193 | /* recognize_eye(pos, *attack_point, *defense_point, *max, *min, eye_data, | |
1194 | * half_eye_data, color, vp), where pos is the origin of an eyespace, returns | |
1195 | * owner of eye (his color) if there is a pattern in eyes.db matching the | |
1196 | * eyespace, or 0 if no match is found. If there is a key point for attack, | |
1197 | * (*attack_point) is set to its location, or NO_MOVE if there is none. | |
1198 | * Similarly (*defense_point) is the location of a vital defense point. | |
1199 | * *value is set according to the pattern found. Vital attack/defense points | |
1200 | * exist if and only if min_eyes(value) != max_eyes(value). | |
1201 | */ | |
1202 | ||
1203 | static int | |
1204 | recognize_eye(int pos, int *attack_point, int *defense_point, | |
1205 | struct eyevalue *value, | |
1206 | struct eye_data eye[BOARDMAX], | |
1207 | struct half_eye_data heye[BOARDMAX], | |
1208 | struct vital_points *vp) | |
1209 | { | |
1210 | int pos2; | |
1211 | int eye_color; | |
1212 | int eye_size = 0; | |
1213 | int num_marginals = 0; | |
1214 | int vpos[MAXEYE]; | |
1215 | signed char marginal[MAXEYE], edge[MAXEYE], neighbors[MAXEYE]; | |
1216 | int graph; | |
1217 | int map[MAXEYE]; | |
1218 | int best_score; | |
1219 | int r; | |
1220 | ||
1221 | gg_assert(attack_point != NULL); | |
1222 | gg_assert(defense_point != NULL); | |
1223 | ||
1224 | /* Set `eye_color' to the owner of the eye. */ | |
1225 | eye_color = eye[pos].color; | |
1226 | ||
1227 | if (eye[pos].esize-eye[pos].msize > 8) | |
1228 | return 0; | |
1229 | ||
1230 | if (eye[pos].msize > MAXEYE) | |
1231 | return 0; | |
1232 | ||
1233 | /* Create list of eye vertices */ | |
1234 | for (pos2 = BOARDMIN; pos2 < BOARDMAX; pos2++) { | |
1235 | if (!ON_BOARD(pos2)) | |
1236 | continue; | |
1237 | if (eye[pos2].origin == pos) { | |
1238 | vpos[eye_size] = pos2; | |
1239 | marginal[eye_size] = eye[pos2].marginal; | |
1240 | if (marginal[eye_size]) | |
1241 | num_marginals++; | |
1242 | neighbors[eye_size] = eye[pos2].neighbors; | |
1243 | if (0) { | |
1244 | if (marginal[eye_size]) | |
1245 | TRACE("(%1m)", vpos[eye_size]); | |
1246 | else | |
1247 | TRACE(" %1m ", vpos[eye_size]); | |
1248 | TRACE("\n"); | |
1249 | } | |
1250 | ||
1251 | if (is_corner_vertex(pos2)) | |
1252 | edge[eye_size] = 2; | |
1253 | else if (is_edge_vertex(pos2)) | |
1254 | edge[eye_size] = 1; | |
1255 | else | |
1256 | edge[eye_size] = 0; | |
1257 | ||
1258 | if (is_halfeye(heye, pos2)) { | |
1259 | neighbors[eye_size]++; /* Increase neighbors of half eye. */ | |
1260 | eye_size++; | |
1261 | /* Use a virtual marginal vertex for mapping purposes. We set it | |
1262 | * to be at NO_MOVE so it won't accidentally count as a | |
1263 | * neighbor for another vertex. Note that the half eye precedes | |
1264 | * the virtual marginal vertex in the list. | |
1265 | */ | |
1266 | vpos[eye_size] = NO_MOVE; | |
1267 | marginal[eye_size] = 1; | |
1268 | num_marginals++; | |
1269 | edge[eye_size] = 0; | |
1270 | neighbors[eye_size] = 1; | |
1271 | } | |
1272 | ||
1273 | eye_size++; | |
1274 | } | |
1275 | } | |
1276 | ||
1277 | /* We attempt to construct a map from the graph to the eyespace | |
1278 | * preserving the adjacency structure. If this can be done, we've | |
1279 | * identified the eyeshape. | |
1280 | */ | |
1281 | ||
1282 | for (graph = 0; graphs[graph].vertex != NULL; graph++) { | |
1283 | int q; | |
1284 | ||
1285 | if (graphs[graph].esize != eye_size | |
1286 | || graphs[graph].msize != num_marginals) | |
1287 | continue; | |
1288 | ||
1289 | reset_map(eye_size); | |
1290 | q = 0; | |
1291 | first_map(&map[0]); | |
1292 | ||
1293 | while (1) { | |
1294 | struct eye_vertex *gv = &graphs[graph].vertex[q]; | |
1295 | int mv = map[q]; | |
1296 | int ok = 1; | |
1297 | ||
1298 | if (0) | |
1299 | TRACE("q=%d: %d %d %d %d %d %d\n", | |
1300 | q, map[0], map[1], map[2], map[3], map[4], map[5]); | |
1301 | ||
1302 | if (neighbors[mv] != gv->neighbors | |
1303 | || marginal[mv] != gv->marginal | |
1304 | || edge[mv] < gv->edge) | |
1305 | ok = 0; | |
1306 | ||
1307 | if (ok) { | |
1308 | if (IS_STONE(board[vpos[mv]])) { | |
1309 | if (!(gv->flags & CAN_CONTAIN_STONE)) | |
1310 | ok = 0; | |
1311 | } | |
1312 | /* Virtual half eye marginals also fall here since they are off | |
1313 | * board. | |
1314 | */ | |
1315 | else if (!(gv->flags & CAN_BE_EMPTY)) | |
1316 | ok = 0; | |
1317 | } | |
1318 | ||
1319 | if (ok) { | |
1320 | int k; | |
1321 | ||
1322 | for (k = 0; k < gv->neighbors; k++) { | |
1323 | if (gv->n[k] < q) { | |
1324 | int mn = map[gv->n[k]]; | |
1325 | ||
1326 | /* Two eye vertices are neighbours if they are adjacent on the | |
1327 | * board or one of them is a half eye and the other is its | |
1328 | * virtual marginal vertex (and follows it in vpos[] array). | |
1329 | */ | |
1330 | if (vpos[mv] != SOUTH(vpos[mn]) | |
1331 | && vpos[mv] != WEST(vpos[mn]) | |
1332 | && vpos[mv] != NORTH(vpos[mn]) | |
1333 | && vpos[mv] != EAST(vpos[mn]) | |
1334 | && (mv != mn - 1 | |
1335 | || vpos[mv] == NO_MOVE | |
1336 | || heye[vpos[mv]].type != HALF_EYE) | |
1337 | && (mn != mv - 1 | |
1338 | || vpos[mn] == NO_MOVE | |
1339 | || heye[vpos[mn]].type != HALF_EYE)) { | |
1340 | ok = 0; | |
1341 | break; | |
1342 | } | |
1343 | } | |
1344 | } | |
1345 | } | |
1346 | ||
1347 | if (!ok) { | |
1348 | if (!next_map(&q, map)) | |
1349 | break; | |
1350 | ||
1351 | if (0) | |
1352 | gprintf(" q=%d, esize=%d: %d %d %d %d %d\n", | |
1353 | q, eye_size, | |
1354 | map[0], map[1], map[2], map[3], map[4]); | |
1355 | } | |
1356 | else { | |
1357 | q++; | |
1358 | if (q == eye_size) | |
1359 | break; /* A match! */ | |
1360 | ||
1361 | first_map(&map[q]); | |
1362 | } | |
1363 | } | |
1364 | ||
1365 | if (q == eye_size) { | |
1366 | /* We have found a match! Now sort out the vital moves. */ | |
1367 | *value = graphs[graph].value; | |
1368 | vp->num_attacks = 0; | |
1369 | vp->num_defenses = 0; | |
1370 | ||
1371 | if (eye_move_urgency(value) > 0) { | |
1372 | /* Collect all attack and defense points in the pattern. */ | |
1373 | int k; | |
1374 | ||
1375 | for (k = 0; k < eye_size; k++) { | |
1376 | struct eye_vertex *ev = &graphs[graph].vertex[k]; | |
1377 | ||
1378 | if (ev->flags & EYE_ATTACK_POINT) { | |
1379 | /* Check for a marginal vertex matching a half eye virtual | |
1380 | * marginal. This is the case if a half eye preceeds the | |
1381 | * current vertex in the list. | |
1382 | */ | |
1383 | if (ev->marginal | |
1384 | && map[k] > 0 | |
1385 | && vpos[map[k] - 1] != NO_MOVE | |
1386 | && is_halfeye(heye, vpos[map[k] - 1])) { | |
1387 | /* Add all diagonals as vital. */ | |
1388 | int ix; | |
1389 | struct half_eye_data *he = &heye[vpos[map[k] - 1]]; | |
1390 | ||
1391 | for (ix = 0; ix < he->num_attacks; ix++) | |
1392 | vp->attacks[vp->num_attacks++] = he->attack_point[ix]; | |
1393 | } | |
1394 | else | |
1395 | vp->attacks[vp->num_attacks++] = vpos[map[k]]; | |
1396 | } | |
1397 | ||
1398 | if (ev->flags & EYE_DEFENSE_POINT) { | |
1399 | /* Check for a half eye virtual marginal vertex. */ | |
1400 | if (ev->marginal | |
1401 | && map[k] > 0 | |
1402 | && vpos[map[k] - 1] != NO_MOVE | |
1403 | && is_halfeye(heye, vpos[map[k] - 1])) { | |
1404 | /* Add all diagonals as vital. */ | |
1405 | int ix; | |
1406 | struct half_eye_data *he = &heye[vpos[map[k] - 1]]; | |
1407 | ||
1408 | for (ix = 0; ix < he->num_defenses; ix++) | |
1409 | vp->defenses[vp->num_defenses++] = he->defense_point[ix]; | |
1410 | } | |
1411 | else | |
1412 | vp->defenses[vp->num_defenses++] = vpos[map[k]]; | |
1413 | } | |
1414 | } | |
1415 | ||
1416 | gg_assert(vp->num_attacks > 0 && vp->num_defenses > 0); | |
1417 | ||
1418 | /* We now have all vital attack and defense points listed but | |
1419 | * we are also expected to single out of one of each to return | |
1420 | * in *attack_point and *defense_point. Since sometimes those | |
1421 | * are the only vital points considered, we want to choose the | |
1422 | * best ones, in the sense that they minimize the risk for | |
1423 | * error in the eye space analysis. | |
1424 | * | |
1425 | * One example is this position | |
1426 | * | |
1427 | * |..XXXX | |
1428 | * |XXX..X | |
1429 | * |..!O.X | |
1430 | * |OO.O.X | |
1431 | * |.O.!XX | |
1432 | * +------ | |
1433 | * | |
1434 | * where O has an eyespace of the !..! type. The graph | |
1435 | * matching finds that both marginal vertices are vital points | |
1436 | * but here the one at 3-3 fails to defend. (For attack both | |
1437 | * points work but the 3-3 one is still worse since it leaves | |
1438 | * a ko threat.) | |
1439 | * | |
1440 | * In order to differentiate between the marginal points we | |
1441 | * count the number of straight and diagonal neighbors within | |
1442 | * the eye space. In the example above both have one straight | |
1443 | * neighbor each but the edge margin wins because it also has | |
1444 | * a diagonal margin. | |
1445 | */ | |
1446 | ||
1447 | best_score = -10; | |
1448 | for (k = 0; k < vp->num_attacks; k++) { | |
1449 | int apos = vp->attacks[k]; | |
1450 | int score = 0; | |
1451 | for (r = 0; r < 8; r++) | |
1452 | if (ON_BOARD(apos + delta[r]) | |
1453 | && eye[apos + delta[r]].color == eye[pos].color | |
1454 | && !eye[apos + delta[r]].marginal) { | |
1455 | score++; | |
1456 | if (r < 4) { | |
1457 | score++; | |
1458 | if (board[apos + delta[r]] != EMPTY) | |
1459 | score++; | |
1460 | } | |
1461 | } | |
1462 | ||
1463 | /* If a vital point is not adjacent to any point in the eye | |
1464 | * space, it must be a move to capture or defend a string | |
1465 | * related to a halfeye, e.g. the move * in this position, | |
1466 | * | |
1467 | * ......| | |
1468 | * .XXXX.| | |
1469 | * .X.O..| | |
1470 | * .XO.OO| | |
1471 | * .*XO..| | |
1472 | * ------+ | |
1473 | * | |
1474 | * Playing this is probably a good idea. | |
1475 | */ | |
1476 | if (score == 0) | |
1477 | score += 2; | |
1478 | ||
1479 | if (0) | |
1480 | gprintf("attack point %1m score %d\n", apos, score); | |
1481 | ||
1482 | if (score > best_score) { | |
1483 | *attack_point = apos; | |
1484 | best_score = score; | |
1485 | } | |
1486 | } | |
1487 | ||
1488 | best_score = -10; | |
1489 | for (k = 0; k < vp->num_defenses; k++) { | |
1490 | int dpos = vp->defenses[k]; | |
1491 | int score = 0; | |
1492 | for (r = 0; r < 8; r++) | |
1493 | if (ON_BOARD(dpos + delta[r]) | |
1494 | && eye[dpos + delta[r]].color == eye[pos].color | |
1495 | && !eye[dpos + delta[r]].marginal) { | |
1496 | score++; | |
1497 | if (r < 4) { | |
1498 | score++; | |
1499 | if (board[dpos + delta[r]] != EMPTY) | |
1500 | score++; | |
1501 | } | |
1502 | } | |
1503 | ||
1504 | /* If possible, choose a non-sacrificial defense point. | |
1505 | * Compare white T8 and T6 in lazarus:21. | |
1506 | */ | |
1507 | if (safe_move(dpos, eye_color) != WIN) | |
1508 | score -= 5; | |
1509 | ||
1510 | /* See comment to the same code for attack points. */ | |
1511 | if (score == 0) | |
1512 | score += 2; | |
1513 | ||
1514 | if (0) | |
1515 | gprintf("defense point %1m score %d\n", dpos, score); | |
1516 | ||
1517 | if (score > best_score) { | |
1518 | *defense_point = dpos; | |
1519 | best_score = score; | |
1520 | } | |
1521 | } | |
1522 | ||
1523 | DEBUG(DEBUG_EYES, " vital points: %1m (attack) %1m (defense)\n", | |
1524 | *attack_point, *defense_point); | |
1525 | DEBUG(DEBUG_EYES, " pattern matched: %d\n", graphs[graph].patnum); | |
1526 | ||
1527 | } | |
1528 | TRACE("eye space at %1m of type %d\n", pos, graphs[graph].patnum); | |
1529 | ||
1530 | return eye_color; | |
1531 | } | |
1532 | } | |
1533 | ||
1534 | return 0; | |
1535 | } | |
1536 | ||
1537 | ||
1538 | /* a MAP is a map of the integers 0,1,2, ... ,q into | |
1539 | * 0,1, ... , esize-1 where q < esize. This determines a | |
1540 | * bijection of the first q+1 elements of the graph into the | |
1541 | * eyespace. The following three functions work with maps. | |
1542 | */ | |
1543 | ||
1544 | /* Reset internal data structure used by first_map() and | |
1545 | * next_map() functions. | |
1546 | */ | |
1547 | static void | |
1548 | reset_map(int size) | |
1549 | { | |
1550 | map_size = size; | |
1551 | memset(used_index, 0, size * sizeof(used_index[0])); | |
1552 | } | |
1553 | ||
1554 | ||
1555 | /* The function first_map finds the smallest valid | |
1556 | * value of a map element. | |
1557 | */ | |
1558 | static void | |
1559 | first_map(int *map_value) | |
1560 | { | |
1561 | int k = 0; | |
1562 | ||
1563 | while (used_index[k]) | |
1564 | k++; | |
1565 | ||
1566 | used_index[k] = 1; | |
1567 | *map_value = k; | |
1568 | } | |
1569 | ||
1570 | ||
1571 | /* The function next_map produces the next map in lexicographical | |
1572 | * order. If no next map can be found, q is decremented, then we | |
1573 | * try again. If the entire map is lexicographically last, the | |
1574 | * function returns false. | |
1575 | */ | |
1576 | static int | |
1577 | next_map(int *q, int map[MAXEYE]) | |
1578 | { | |
1579 | int k; | |
1580 | ||
1581 | do { | |
1582 | used_index[map[*q]] = 0; | |
1583 | for (k = map[*q]; ++k < map_size;) { | |
1584 | if (!used_index[k]) { | |
1585 | used_index[k] = 1; | |
1586 | map[*q] = k; | |
1587 | return 1; | |
1588 | } | |
1589 | } | |
1590 | ||
1591 | (*q)--; | |
1592 | } while (*q >= 0); | |
1593 | ||
1594 | return 0; | |
1595 | } | |
1596 | ||
1597 | ||
1598 | /* add_false_eye() turns a proper eyespace into a margin. */ | |
1599 | ||
1600 | static void | |
1601 | add_false_eye(int pos, struct eye_data eye[BOARDMAX], | |
1602 | struct half_eye_data heye[BOARDMAX]) | |
1603 | { | |
1604 | int k; | |
1605 | ASSERT1(heye[pos].type == FALSE_EYE, pos); | |
1606 | DEBUG(DEBUG_EYES, "false eye found at %1m\n", pos); | |
1607 | ||
1608 | if (eye[pos].color == GRAY || eye[pos].marginal != 0) | |
1609 | return; | |
1610 | ||
1611 | eye[pos].marginal = 1; | |
1612 | eye[eye[pos].origin].msize++; | |
1613 | for (k = 0; k < 4; k++) | |
1614 | if (ON_BOARD(pos + delta[k]) | |
1615 | && eye[pos + delta[k]].origin == eye[pos].origin) | |
1616 | eye[pos + delta[k]].marginal_neighbors++; | |
1617 | propagate_eye(eye[pos].origin, eye); | |
1618 | } | |
1619 | ||
1620 | ||
1621 | /* These functions are used from constraints to identify eye spaces, | |
1622 | * primarily for late endgame moves. | |
1623 | */ | |
1624 | int | |
1625 | is_eye_space(int pos) | |
1626 | { | |
1627 | return (white_eye[pos].color == WHITE | |
1628 | || black_eye[pos].color == BLACK); | |
1629 | } | |
1630 | ||
1631 | int | |
1632 | is_proper_eye_space(int pos) | |
1633 | { | |
1634 | return ((white_eye[pos].color == WHITE && !white_eye[pos].marginal) | |
1635 | || (black_eye[pos].color == BLACK && !black_eye[pos].marginal)); | |
1636 | } | |
1637 | ||
1638 | /* Return the maximum number of eyes that can be obtained from the | |
1639 | * eyespace at (i, j). This is most useful in order to determine | |
1640 | * whether the eyespace can be assumed to produce any territory at | |
1641 | * all. | |
1642 | */ | |
1643 | int | |
1644 | max_eye_value(int pos) | |
1645 | { | |
1646 | int max_white = 0; | |
1647 | int max_black = 0; | |
1648 | ||
1649 | if (white_eye[pos].color == WHITE) | |
1650 | max_white = max_eyes(&white_eye[pos].value); | |
1651 | ||
1652 | if (black_eye[pos].color == BLACK) | |
1653 | max_black = max_eyes(&black_eye[pos].value); | |
1654 | ||
1655 | return gg_max(max_white, max_black); | |
1656 | } | |
1657 | ||
1658 | int | |
1659 | is_marginal_eye_space(int pos) | |
1660 | { | |
1661 | return (white_eye[pos].marginal || black_eye[pos].marginal); | |
1662 | } | |
1663 | ||
1664 | int | |
1665 | is_halfeye(struct half_eye_data heye[BOARDMAX], int pos) | |
1666 | { | |
1667 | return heye[pos].type == HALF_EYE; | |
1668 | } | |
1669 | ||
1670 | int | |
1671 | is_false_eye(struct half_eye_data heye[BOARDMAX], int pos) | |
1672 | { | |
1673 | return heye[pos].type == FALSE_EYE; | |
1674 | } | |
1675 | ||
1676 | ||
1677 | /* Find topological half eyes and false eyes by analyzing the | |
1678 | * diagonal intersections, as described in the Texinfo | |
1679 | * documentation (Eyes/Eye Topology). | |
1680 | */ | |
1681 | void | |
1682 | find_half_and_false_eyes(int color, struct eye_data eye[BOARDMAX], | |
1683 | struct half_eye_data heye[BOARDMAX], | |
1684 | int find_mask[BOARDMAX]) | |
1685 | { | |
1686 | int eye_color = color; | |
1687 | int pos; | |
1688 | float sum; | |
1689 | ||
1690 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
1691 | /* skip eyespaces which owl doesn't want to be searched */ | |
1692 | if (!ON_BOARD(pos) || (find_mask && find_mask[eye[pos].origin] <= 1)) | |
1693 | continue; | |
1694 | ||
1695 | /* skip every vertex which can't be a false or half eye */ | |
1696 | if (eye[pos].color != eye_color | |
1697 | || eye[pos].marginal | |
1698 | || eye[pos].neighbors > 1) | |
1699 | continue; | |
1700 | ||
1701 | sum = topological_eye(pos, color, eye, heye); | |
1702 | if (sum >= 4.0) { | |
1703 | /* false eye */ | |
1704 | heye[pos].type = FALSE_EYE; | |
1705 | if (eye[pos].esize == 1 | |
1706 | || is_legal(pos, OTHER_COLOR(color)) | |
1707 | || board[pos] == OTHER_COLOR(color)) | |
1708 | add_false_eye(pos, eye, heye); | |
1709 | } | |
1710 | else if (sum > 2.0) { | |
1711 | /* half eye */ | |
1712 | heye[pos].type = HALF_EYE; | |
1713 | ASSERT1(heye[pos].num_attacks > 0, pos); | |
1714 | ASSERT_ON_BOARD1(heye[pos].attack_point[0]); | |
1715 | ASSERT1(heye[pos].num_defenses > 0, pos); | |
1716 | ASSERT_ON_BOARD1(heye[pos].defense_point[0]); | |
1717 | } | |
1718 | } | |
1719 | } | |
1720 | ||
1721 | ||
1722 | /* See Texinfo documentation (Eyes:Eye Topology). Returns: | |
1723 | * - 2 or less if (pos) is a proper eye for (color); | |
1724 | * - between 2 and 3 if the eye can be made false only by ko | |
1725 | * - 3 if (pos) is a half eye; | |
1726 | * - between 3 and 4 if the eye can be made real only by ko | |
1727 | * - 4 or more if (pos) is a false eye. | |
1728 | * | |
1729 | * Attack and defense points for control of the diagonals are stored | |
1730 | * in the heye[] array. | |
1731 | * | |
1732 | * my_eye is the eye space information with respect to (color). | |
1733 | */ | |
1734 | ||
1735 | static float | |
1736 | topological_eye(int pos, int color, | |
1737 | struct eye_data my_eye[BOARDMAX], | |
1738 | struct half_eye_data heye[BOARDMAX]) | |
1739 | { | |
1740 | float sum = 0.0; | |
1741 | float val; | |
1742 | int num_attacks = 0; | |
1743 | int num_defenses = 0; | |
1744 | int attack_values[4]; | |
1745 | int defense_values[4]; | |
1746 | int k; | |
1747 | int r; | |
1748 | int attack_point; | |
1749 | int defense_point; | |
1750 | int attack_value; | |
1751 | int defense_value; | |
1752 | ||
1753 | memset(attack_values, 0, sizeof(attack_values)); | |
1754 | memset(defense_values, 0, sizeof(defense_values)); | |
1755 | ||
1756 | /* Loop over the diagonal directions. */ | |
1757 | for (k = 4; k < 8; k++) { | |
1758 | int diag = pos + delta[k]; | |
1759 | val = evaluate_diagonal_intersection(I(pos) + deltai[k], | |
1760 | J(pos) + deltaj[k], color, | |
1761 | &attack_point, &defense_point, | |
1762 | my_eye); | |
1763 | ||
1764 | /* | |
1765 | * Eyespaces with cutting points are problematic. In this position | |
1766 | * | |
1767 | * .....XXXXX | |
1768 | * XXXXX.OO.X | |
1769 | * X.OOOO.O.X | |
1770 | * X.O.XXXO.X | |
1771 | * ---------- | |
1772 | * | |
1773 | * the eyespace will be .XXX. which evaluates to two eyes (seki) | |
1774 | * unless countermeasures are taken. | |
1775 | * | |
1776 | * This can be worked around in the topological analysis by | |
1777 | * sometimes setting the diagonal value to 2.0 for vertices inside | |
1778 | * the eyespace which are occupied by opponent stones. More | |
1779 | * precisely all of the following conditions must hold: | |
1780 | * | |
1781 | * a) The value is not already 2.0. | |
1782 | * a) The (potential) eyepoint is empty. | |
1783 | * b) The diagonal is occupied by an opponent string, | |
1784 | * c) which is also adjacent to the (potential) eye and | |
1785 | * d) at least three stones long. | |
1786 | * e) The (potential) eye is not on the edge (to steer clear of all the | |
1787 | * hairy cases that are handled by eyes.db anyway). | |
1788 | * f) At least two own strings are adjacent to the (potential) eye. | |
1789 | * g) At least one of the own strings adjacent to the (potential) eye has | |
1790 | * only one liberty which is an eye space and not decided false, yet. | |
1791 | * | |
1792 | * With this revision the eyespace above becomes .XXXh or | |
1793 | * equivalently .XXX.! which is almost evaluated correctly, eye | |
1794 | * value 0122 instead of the correct 1122. Compared to the | |
1795 | * previous value 2222 it's a major improvement. | |
1796 | * | |
1797 | * FIXME: This approach has a number of shortcomings. | |
1798 | * | |
1799 | * 1. d) is kind of arbitrary and there may be exceptional | |
1800 | * cases. | |
1801 | * | |
1802 | * 2. This diagonal value modification should not apply to | |
1803 | * two diagonals of the same strings inside the eyespace. | |
1804 | * E.g. if we have a partial eyespace looking like | |
1805 | * | |
1806 | * .OOO. | |
1807 | * OO.OO | |
1808 | * OXXXO | |
1809 | * | |
1810 | * it doesn't make sense to mark the middle vertex as a | |
1811 | * false eye. Possibly this doesn't make any difference | |
1812 | * in practice but it's at the very least confusing. | |
1813 | * | |
1814 | * 3. Actually it doesn't make sense to mark vertices as | |
1815 | * false otherwise either due to these revisions (half | |
1816 | * eyes make good sense though) as can be seen if a | |
1817 | * stone is added to the initial diagram, | |
1818 | * | |
1819 | * .....XXXXX | |
1820 | * XXXXXXOO.X | |
1821 | * X.OOOO.O.X | |
1822 | * X.O.XXXO.X | |
1823 | * ---------- | |
1824 | * | |
1825 | * Now the eyespace instead becomes .XXX! which has the | |
1826 | * eye value 0011 but if X tries to attack the eye O | |
1827 | * suddenly gets two solid eyes! | |
1828 | * | |
1829 | * The correct analysis would be to remove the vertex | |
1830 | * from the eyespace rather than turning it into a false | |
1831 | * eye. Then we would have the eyespace .XXX which is | |
1832 | * correctly evaluated to one eye (eye value 1112). | |
1833 | * | |
1834 | * The problem with this is that removing eye points is | |
1835 | * messy. It can surely be done but currently there is | |
1836 | * no support in the code for doing that. It has existed | |
1837 | * at an earlier time but was removed because the | |
1838 | * implementation was not robust enough and there was no | |
1839 | * longer any apparent need for it. To correct this | |
1840 | * problem is sufficient reason to reimplement that | |
1841 | * functionality. | |
1842 | * | |
1843 | * 4. The test of condition g) has a result which | |
1844 | * potentially depends on the ordering of the eyespaces | |
1845 | * and thus presumably on the orientation of the board. | |
1846 | * It might make more sense to examine whether the | |
1847 | * string neighbors more than one empty vertex in the | |
1848 | * same eyespace. | |
1849 | */ | |
1850 | if (val < 2.0 && board[pos] == EMPTY && board[diag] == OTHER_COLOR(color) | |
1851 | && !is_edge_vertex(pos) && neighbor_of_string(pos, diag) | |
1852 | && countstones(diag) >= 3) { | |
1853 | int strings[3]; | |
1854 | int string_count; | |
1855 | int s; | |
1856 | string_count = 0; | |
1857 | for (r = 0; r < 4; r++) { | |
1858 | int str; | |
1859 | str = pos + delta[r]; | |
1860 | ||
1861 | if (board[str] != color) | |
1862 | continue; | |
1863 | ||
1864 | ASSERT1(string_count < 3, pos); | |
1865 | for (s = 0; s < string_count; s++) | |
1866 | if (same_string(str, strings[s])) | |
1867 | break; | |
1868 | if (s != string_count) | |
1869 | continue; | |
1870 | ||
1871 | strings[string_count++] = str; | |
1872 | } | |
1873 | if (string_count > 1) { | |
1874 | for (s = 0; s < string_count; s++) { | |
1875 | int libs[MAX_LIBERTIES]; | |
1876 | int adj_eye_count; | |
1877 | int lib_count; | |
1878 | adj_eye_count = 0; | |
1879 | lib_count = findlib(strings[s], MAX_LIBERTIES, libs); | |
1880 | if (lib_count > MAX_LIBERTIES) | |
1881 | continue; | |
1882 | ||
1883 | for (r = 0; r < lib_count && adj_eye_count < 2; r++) | |
1884 | if (my_eye[libs[r]].color == OTHER_COLOR(color) | |
1885 | && !my_eye[libs[r]].marginal) | |
1886 | adj_eye_count++; | |
1887 | if (adj_eye_count < 2) { | |
1888 | val = 2.0; | |
1889 | break; | |
1890 | } | |
1891 | } | |
1892 | } | |
1893 | } | |
1894 | ||
1895 | sum += val; | |
1896 | ||
1897 | if (val > 0.0 && val < 2.0) { | |
1898 | /* Diagonals off the edge has value 1.0 but no attack or defense | |
1899 | * point. | |
1900 | */ | |
1901 | if (attack_point != NO_MOVE && defense_point != NO_MOVE) { | |
1902 | ASSERT_ON_BOARD1(attack_point); | |
1903 | ASSERT_ON_BOARD1(defense_point); | |
1904 | /* Store these in sorted (descending) order. We remap val | |
1905 | * differently for attack and defense points according to: | |
1906 | * | |
1907 | * val attack_value defense_value | |
1908 | * --- ------------ ------------- | |
1909 | * 1.0 3 3 | |
1910 | * <1.0 2 1 | |
1911 | * >1.0 1 2 | |
1912 | * | |
1913 | * This means that we primarily want to take control of | |
1914 | * diagonals without ko and secondarily of diagonals we can | |
1915 | * take unconditionally but not the opponent. | |
1916 | */ | |
1917 | if (val == 1.0) { | |
1918 | attack_value = 3; | |
1919 | defense_value = 3; | |
1920 | } | |
1921 | else if (val < 1.0) { | |
1922 | attack_value = 2; | |
1923 | defense_value = 1; | |
1924 | } | |
1925 | else { | |
1926 | attack_value = 1; | |
1927 | defense_value = 2; | |
1928 | } | |
1929 | ||
1930 | for (r = 0; r < 4; r++) { | |
1931 | if (attack_values[r] < attack_value) { | |
1932 | int tmp_value = attack_values[r]; | |
1933 | int tmp_point; | |
1934 | if (tmp_value) | |
1935 | tmp_point = heye[pos].attack_point[r]; | |
1936 | else | |
1937 | tmp_point = 0; | |
1938 | attack_values[r] = attack_value; | |
1939 | heye[pos].attack_point[r] = attack_point; | |
1940 | attack_value = tmp_value; | |
1941 | attack_point = tmp_point; | |
1942 | } | |
1943 | ||
1944 | if (defense_values[r] < defense_value) { | |
1945 | int tmp_value = defense_values[r]; | |
1946 | int tmp_point; | |
1947 | if (tmp_value) | |
1948 | tmp_point = heye[pos].defense_point[r]; | |
1949 | else | |
1950 | tmp_point = 0; | |
1951 | defense_values[r] = defense_value; | |
1952 | heye[pos].defense_point[r] = defense_point; | |
1953 | defense_value = tmp_value; | |
1954 | defense_point = tmp_point; | |
1955 | } | |
1956 | } | |
1957 | ||
1958 | num_attacks++; | |
1959 | num_defenses++; | |
1960 | } | |
1961 | } | |
1962 | } | |
1963 | ||
1964 | /* Remove attacks and defenses with smaller value than the best | |
1965 | * ones. (These might be useful to save as well, but not unless we | |
1966 | * also store the attack/defense values in the half_eye_data.) | |
1967 | */ | |
1968 | for (r = 0; r < num_attacks; r++) { | |
1969 | if (attack_values[r] < attack_values[0]) { | |
1970 | num_attacks = r; | |
1971 | break; | |
1972 | } | |
1973 | } | |
1974 | ||
1975 | for (r = 0; r < num_defenses; r++) { | |
1976 | if (defense_values[r] < defense_values[0]) { | |
1977 | num_defenses = r; | |
1978 | break; | |
1979 | } | |
1980 | } | |
1981 | ||
1982 | heye[pos].num_attacks = num_attacks; | |
1983 | heye[pos].num_defenses = num_defenses; | |
1984 | heye[pos].value = sum; | |
1985 | ||
1986 | return sum; | |
1987 | } | |
1988 | ||
1989 | ||
1990 | ||
1991 | /* Evaluate an intersection (m, n) which is diagonal to an eye space, | |
1992 | * as described in the Texinfo documentation (Eyes/Eye Topology). | |
1993 | * | |
1994 | * Returns: | |
1995 | * | |
1996 | * 0 if both coordinates are off the board | |
1997 | * 1 if one coordinate is off the board | |
1998 | * | |
1999 | * 0 if (color) has control over the vertex | |
2000 | * a if (color) can take control over the vertex unconditionally and | |
2001 | * the opponent can take control by winning a ko. | |
2002 | * 1 if both (color) and the opponent can take control of the vertex | |
2003 | * unconditionally | |
2004 | * b if (color) can take control over the vertex by winning a ko and | |
2005 | * the opponent can take control unconditionally. | |
2006 | * 2 if the opponent has control over the vertex | |
2007 | * | |
2008 | * The values a and b are discussed in the documentation. We are | |
2009 | * currently using a = 0.75 and b = 1.25. | |
2010 | * | |
2011 | * Notice that it's necessary to pass the coordinates separately | |
2012 | * instead of as a 1D coordinate. The reason is that the 1D mapping | |
2013 | * can't uniquely identify "off the corner" points. | |
2014 | * | |
2015 | * my_eye has to be the eye_data with respect to color. | |
2016 | */ | |
2017 | static float | |
2018 | evaluate_diagonal_intersection(int m, int n, int color, | |
2019 | int *attack_point, int *defense_point, | |
2020 | struct eye_data my_eye[BOARDMAX]) | |
2021 | { | |
2022 | float value = 0; | |
2023 | int other = OTHER_COLOR(color); | |
2024 | int pos = POS(m, n); | |
2025 | int acode = 0; | |
2026 | int apos = NO_MOVE; | |
2027 | int dcode = 0; | |
2028 | int dpos = NO_MOVE; | |
2029 | int off_edge = 0; | |
2030 | const float a = 0.75; | |
2031 | const float b = 2 - a; | |
2032 | ||
2033 | *attack_point = NO_MOVE; | |
2034 | *defense_point = NO_MOVE; | |
2035 | ||
2036 | /* Check whether intersection is off the board. We must do this for | |
2037 | * each board coordinate separately because points "off the corner" | |
2038 | * are special cases. | |
2039 | */ | |
2040 | if (m < 0 || m >= board_size) | |
2041 | off_edge++; | |
2042 | ||
2043 | if (n < 0 || n >= board_size) | |
2044 | off_edge++; | |
2045 | ||
2046 | /* Must return 0 if both coordinates out of bounds. */ | |
2047 | if (off_edge > 0) | |
2048 | return (float) (off_edge % 2); | |
2049 | ||
2050 | /* Discard points within own eyespace, unless marginal or ko point. | |
2051 | * | |
2052 | * Comment: For some time discardment of points within own eyespace | |
2053 | * was contingent on this being the same eyespace as that of the | |
2054 | * examined vertex. This caused problems, e.g. in this position, | |
2055 | * | |
2056 | * |........ | |
2057 | * |XXXXX... | |
2058 | * |OOOOX... | |
2059 | * |aO.OX... | |
2060 | * |OXXOX... | |
2061 | * |.XXOX... | |
2062 | * +-------- | |
2063 | * | |
2064 | * where the empty vertex at a was evaluated as a false eye and the | |
2065 | * whole group as dead (instead of living in seki). | |
2066 | * | |
2067 | * The reason for the requirement of less than two marginal | |
2068 | * neighbors is this position: | |
2069 | * | |
2070 | * |.XXXX... | |
2071 | * |.OOOX... | |
2072 | * |O..OX... | |
2073 | * |aOO.X... | |
2074 | * |O..XX... | |
2075 | * |..O.X... | |
2076 | * |.X..X... | |
2077 | * |..XXX... | |
2078 | * | |
2079 | * where the empty vertex at a should not count as a solid eye. | |
2080 | * (The eyespace diagonally below a looks like this: | |
2081 | * .! | |
2082 | * ! | |
2083 | * so we can clearly see why having two marginal vertices makes a | |
2084 | * difference.) | |
2085 | */ | |
2086 | if (my_eye[pos].color == color | |
2087 | && !my_eye[pos].marginal | |
2088 | && my_eye[pos].marginal_neighbors < 2 | |
2089 | && !(board[pos] == EMPTY && does_capture_something(pos, other))) | |
2090 | return 0.0; | |
2091 | ||
2092 | if (board[pos] == EMPTY) { | |
2093 | int your_safety = safe_move(pos, other); | |
2094 | ||
2095 | apos = pos; | |
2096 | dpos = pos; | |
2097 | ||
2098 | /* We should normally have a safe move, but occasionally it may | |
2099 | * happen that it's not safe. There are complications, however, | |
2100 | * with a position like this: | |
2101 | * | |
2102 | * .XXXX| | |
2103 | * XXOO.| | |
2104 | * XO.O.| | |
2105 | * XXO.O| | |
2106 | * -----+ | |
2107 | * | |
2108 | * Therefore we ignore our own safety if opponent's safety depends | |
2109 | * on ko. | |
2110 | */ | |
2111 | if (your_safety == 0) | |
2112 | value = 0.0; | |
2113 | else if (your_safety != WIN) | |
2114 | value = a; | |
2115 | else { /* So your_safety == WIN. */ | |
2116 | int our_safety = safe_move(pos, color); | |
2117 | ||
2118 | if (our_safety == 0) { | |
2119 | int k; | |
2120 | ||
2121 | value = 2.0; | |
2122 | ||
2123 | /* This check is intended to fix a certain special case, but might | |
2124 | * be helpful in other situations as well. Consider this position, | |
2125 | * happened in owl reading deep enough: | |
2126 | * | |
2127 | * |XXXXX | |
2128 | * |XOOXX | |
2129 | * |O.OOX | |
2130 | * |.OXX. | |
2131 | * +----- | |
2132 | * | |
2133 | * Without this check, the corner eye is considered false, not half- | |
2134 | * eye. Thus, owl thinks that the capture gains at most one eye and | |
2135 | * gives up. | |
2136 | */ | |
2137 | for (k = 4; k < 8; k++) { | |
2138 | int diagonal = pos + delta[k]; | |
2139 | int lib; | |
2140 | ||
2141 | if (board[diagonal] == other && findlib(diagonal, 1, &lib) == 1) { | |
2142 | if (lib != pos && does_secure(color, lib, pos)) { | |
2143 | value = 1.0; | |
2144 | apos = lib; | |
2145 | break; | |
2146 | } | |
2147 | } | |
2148 | } | |
2149 | } | |
2150 | else if (our_safety == WIN) | |
2151 | value = 1.0; | |
2152 | else /* our_safety depends on ko. */ | |
2153 | value = b; | |
2154 | } | |
2155 | } | |
2156 | else if (board[pos] == color) { | |
2157 | /* This stone had better be safe, otherwise we wouldn't have an | |
2158 | * eyespace in the first place. | |
2159 | */ | |
2160 | value = 0.0; | |
2161 | } | |
2162 | else if (board[pos] == other) { | |
2163 | if (stackp == 0) { | |
2164 | acode = worm[pos].attack_codes[0]; | |
2165 | apos = worm[pos].attack_points[0]; | |
2166 | dcode = worm[pos].defense_codes[0]; | |
2167 | dpos = worm[pos].defense_points[0]; | |
2168 | } | |
2169 | else | |
2170 | attack_and_defend(pos, &acode, &apos, &dcode, &dpos); | |
2171 | ||
2172 | /* Must test acode first since dcode only is reliable if acode is | |
2173 | * non-zero. | |
2174 | */ | |
2175 | if (acode == 0) | |
2176 | value = 2.0; | |
2177 | else if (dcode == 0) | |
2178 | value = 0.0; | |
2179 | else if (acode == WIN && dcode == WIN) | |
2180 | value = 1.0; | |
2181 | else if (acode == WIN && dcode != WIN) | |
2182 | value = a; | |
2183 | else if (acode != WIN && dcode == WIN) | |
2184 | value = b; | |
2185 | else if (acode != WIN && dcode != WIN) | |
2186 | value = 1.0; /* Both contingent on ko. Probably can't happen. */ | |
2187 | } | |
2188 | ||
2189 | if (value > 0.0 && value < 2.0) { | |
2190 | /* FIXME: | |
2191 | * Usually there are several attack and defense moves that would | |
2192 | * be equally valid. It's not good that we make an arbitrary | |
2193 | * choice at this point. | |
2194 | */ | |
2195 | ASSERT_ON_BOARD1(apos); | |
2196 | ASSERT_ON_BOARD1(dpos); | |
2197 | /* Notice: | |
2198 | * The point to ATTACK the half eye is the point which DEFENDS | |
2199 | * the stones on the diagonal intersection and vice versa. Thus | |
2200 | * we must switch attack and defense points here. | |
2201 | * If the vertex is empty, dpos == apos and it doesn't matter | |
2202 | * whether we switch. | |
2203 | */ | |
2204 | *attack_point = dpos; | |
2205 | *defense_point = apos; | |
2206 | } | |
2207 | ||
2208 | return value; | |
2209 | } | |
2210 | ||
2211 | ||
2212 | /* Conservative relative of topological_eye(). Essentially the same | |
2213 | * algorithm is used, but only tactically safe opponent strings on | |
2214 | * diagonals are considered. This may underestimate the false/half eye | |
2215 | * status, but it should never be overestimated. | |
2216 | */ | |
2217 | int | |
2218 | obvious_false_eye(int pos, int color) | |
2219 | { | |
2220 | int i = I(pos); | |
2221 | int j = J(pos); | |
2222 | int k; | |
2223 | int diagonal_sum = 0; | |
2224 | for (k = 4; k < 8; k++) { | |
2225 | int di = deltai[k]; | |
2226 | int dj = deltaj[k]; | |
2227 | ||
2228 | if (!ON_BOARD2(i+di, j) && !ON_BOARD2(i, j+dj)) | |
2229 | diagonal_sum--; | |
2230 | ||
2231 | if (!ON_BOARD2(i+di, j+dj)) | |
2232 | diagonal_sum++; | |
2233 | else if (BOARD(i+di, j+dj) == OTHER_COLOR(color) | |
2234 | && !attack(POS(i+di, j+dj), NULL)) | |
2235 | diagonal_sum += 2; | |
2236 | } | |
2237 | ||
2238 | return diagonal_sum >= 4; | |
2239 | } | |
2240 | ||
2241 | ||
2242 | /* Set the parameters into struct eyevalue as follows: | |
2243 | a = number of eyes if attacker plays first twice | |
2244 | b = number of eyes if attacker plays first | |
2245 | c = number of eyes if defender plays first | |
2246 | d =number of eyes if defender plays first twice | |
2247 | */ | |
2248 | ||
2249 | void | |
2250 | set_eyevalue(struct eyevalue *e, int a, int b, int c, int d) | |
2251 | { | |
2252 | e->a = a; | |
2253 | e->b = b; | |
2254 | e->c = c; | |
2255 | e->d = d; | |
2256 | } | |
2257 | ||
2258 | /* Number of eyes if attacker plays first twice (the threat of the first | |
2259 | * move by attacker). | |
2260 | */ | |
2261 | int | |
2262 | min_eye_threat(struct eyevalue *e) | |
2263 | { | |
2264 | return e->a; | |
2265 | } | |
2266 | ||
2267 | /* Number of eyes if attacker plays first followed by alternating play. */ | |
2268 | int | |
2269 | min_eyes(struct eyevalue *e) | |
2270 | { | |
2271 | return e->b; | |
2272 | } | |
2273 | ||
2274 | /* Number of eyes if defender plays first followed by alternating play. */ | |
2275 | int | |
2276 | max_eyes(struct eyevalue *e) | |
2277 | { | |
2278 | return e->c; | |
2279 | } | |
2280 | ||
2281 | /* Number of eyes if defender plays first twice (the threat of the first | |
2282 | * move by defender). | |
2283 | */ | |
2284 | int | |
2285 | max_eye_threat(struct eyevalue *e) | |
2286 | { | |
2287 | return e->d; | |
2288 | } | |
2289 | ||
2290 | /* Add the eyevalues *e1 and *e2, leaving the result in *sum. It is | |
2291 | * safe to let sum be the same as e1 or e2. | |
2292 | */ | |
2293 | void | |
2294 | add_eyevalues(struct eyevalue *e1, struct eyevalue *e2, struct eyevalue *sum) | |
2295 | { | |
2296 | struct eyevalue res; | |
2297 | res.a = gg_min(gg_min(e1->a + e2->c, e1->c + e2->a), | |
2298 | gg_max(e1->a + e2->b, e1->b + e2->a)); | |
2299 | res.b = gg_min(gg_max(e1->b + e2->b, gg_min(e1->a + e2->d, e1->b + e2->c)), | |
2300 | gg_max(e1->b + e2->b, gg_min(e1->d + e2->a, e1->c + e2->b))); | |
2301 | res.c = gg_max(gg_min(e1->c + e2->c, gg_max(e1->d + e2->a, e1->c + e2->b)), | |
2302 | gg_min(e1->c + e2->c, gg_max(e1->a + e2->d, e1->b + e2->c))); | |
2303 | res.d = gg_max(gg_max(e1->d + e2->b, e1->b + e2->d), | |
2304 | gg_min(e1->d + e2->c, e1->c + e2->d)); | |
2305 | ||
2306 | /* The rules above give 0011 + 0002 = 0012, which is incorrect. Thus | |
2307 | * we need this annoying exception. | |
2308 | */ | |
2309 | if ((e1->d - e1->c == 2 && e2->c - e2->b == 1) | |
2310 | || (e1->c - e1->b == 1 && e2->d - e2->c == 2)) { | |
2311 | res.d = gg_max(gg_min(e1->c + e2->d, e1->d + e2->b), | |
2312 | gg_min(e1->d + e2->c, e1->b + e2->d)); | |
2313 | } | |
2314 | ||
2315 | /* The temporary storage in res is necessary if sum is the same as | |
2316 | * e1 or e2. | |
2317 | */ | |
2318 | sum->a = res.a; | |
2319 | sum->b = res.b; | |
2320 | sum->c = res.c; | |
2321 | sum->d = res.d; | |
2322 | } | |
2323 | ||
2324 | /* The impact on the number of eyes (counting up to two) if a vital | |
2325 | * move is made. The possible values are | |
2326 | * 0 - settled eye, no vital move | |
2327 | * 2 - 1/2 eye or 3/2 eyes | |
2328 | * 3 - 3/4 eyes or 5/4 eyes | |
2329 | * 4 - 1* eyes (a chimera) | |
2330 | */ | |
2331 | int | |
2332 | eye_move_urgency(struct eyevalue *e) | |
2333 | { | |
2334 | int a = gg_min(e->a, 2); | |
2335 | int b = gg_min(e->b, 2); | |
2336 | int c = gg_min(e->c, 2); | |
2337 | int d = gg_min(e->d, 2); | |
2338 | if (b == c) | |
2339 | return 0; | |
2340 | else | |
2341 | return d + c - b - a; | |
2342 | } | |
2343 | ||
2344 | /* Produces a string representing the eyevalue. | |
2345 | * | |
2346 | * Note: the result string is stored in a statically allocated buffer | |
2347 | * which will be overwritten the next time this function is called. | |
2348 | */ | |
2349 | char * | |
2350 | eyevalue_to_string(struct eyevalue *e) | |
2351 | { | |
2352 | static char result[30]; | |
2353 | if (e->a < 10 && e->b < 10 && e->c < 10 && e->d < 10) | |
2354 | gg_snprintf(result, 29, "%d%d%d%d", e->a, e->b, e->c, e->d); | |
2355 | else | |
2356 | gg_snprintf(result, 29, "[%d,%d,%d,%d]", e->a, e->b, e->c, e->d); | |
2357 | return result; | |
2358 | } | |
2359 | ||
2360 | ||
2361 | ||
2362 | /* Test whether the optics code evaluates an eyeshape consistently. */ | |
2363 | void | |
2364 | test_eyeshape(int eyesize, int *eye_vertices) | |
2365 | { | |
2366 | int k; | |
2367 | int n, N; | |
2368 | int mx[BOARDMAX]; | |
2369 | int pos; | |
2370 | int str = NO_MOVE; | |
2371 | int attack_code; | |
2372 | int attack_point; | |
2373 | int defense_code; | |
2374 | int defense_point; | |
2375 | int save_verbose; | |
2376 | struct board_state starting_position; | |
2377 | ||
2378 | /* Clear the board and initialize the engine properly. */ | |
2379 | clear_board(); | |
2380 | reset_engine(); | |
2381 | ||
2382 | /* Mark the eyespace in the mx array. */ | |
2383 | memset(mx, 0, sizeof(mx)); | |
2384 | for (k = 0; k < eyesize; k++) { | |
2385 | ASSERT_ON_BOARD1(eye_vertices[k]); | |
2386 | mx[eye_vertices[k]] = 1; | |
2387 | } | |
2388 | ||
2389 | /* Play white stones surrounding the eyespace, including diagonals. */ | |
2390 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
2391 | if (!ON_BOARD(pos) || mx[pos] == 1) | |
2392 | continue; | |
2393 | for (k = 0; k < 8; k++) { | |
2394 | if (ON_BOARD(pos + delta[k]) && mx[pos + delta[k]] == 1) { | |
2395 | play_move(pos, WHITE); | |
2396 | str = pos; | |
2397 | break; | |
2398 | } | |
2399 | } | |
2400 | } | |
2401 | ||
2402 | /* Play black stones surrounding the white group, but leaving all | |
2403 | * liberties empty. | |
2404 | */ | |
2405 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { | |
2406 | if (mx[pos] == 1 || board[pos] != EMPTY || liberty_of_string(pos, str)) | |
2407 | continue; | |
2408 | for (k = 0; k < 8; k++) { | |
2409 | if (ON_BOARD(pos + delta[k]) | |
2410 | && liberty_of_string(pos + delta[k], str)) { | |
2411 | play_move(pos, BLACK); | |
2412 | break; | |
2413 | } | |
2414 | } | |
2415 | } | |
2416 | ||
2417 | /* Show the board if verbose is on. Then turn off traces so we don't | |
2418 | * get any from make_worms(), make_dragons(), or the owl reading. | |
2419 | */ | |
2420 | if (verbose) | |
2421 | showboard(0); | |
2422 | save_verbose = verbose; | |
2423 | verbose = 0; | |
2424 | ||
2425 | ||
2426 | /* Store this position so we can come back to it. */ | |
2427 | store_board(&starting_position); | |
2428 | ||
2429 | /* Loop over all configurations of black stones inserted in the | |
2430 | * eyeshape. There are N = 2^(eyesize) configurations and we can | |
2431 | * straightforwardly use binary representation to enumerate them. | |
2432 | */ | |
2433 | N = 1 << eyesize; | |
2434 | for (n = 0; n < N; n++) { | |
2435 | int valid = 1; | |
2436 | int internal_stones = 0; | |
2437 | ||
2438 | restore_board(&starting_position); | |
2439 | /* Play the stones for this configuration. */ | |
2440 | for (k = 0; k < eyesize; k++) { | |
2441 | if (n & (1 << k)) { | |
2442 | if (!is_legal(eye_vertices[k], BLACK)) { | |
2443 | valid = 0; | |
2444 | break; | |
2445 | } | |
2446 | play_move(eye_vertices[k], BLACK); | |
2447 | internal_stones++; | |
2448 | } | |
2449 | } | |
2450 | ||
2451 | if (!valid) | |
2452 | continue; | |
2453 | ||
2454 | if (save_verbose > 1) | |
2455 | showboard(0); | |
2456 | ||
2457 | /* Now we are ready to test the consistency. This is most easily | |
2458 | * done with help from the owl code. First we must prepare for | |
2459 | * this though. | |
2460 | */ | |
2461 | examine_position(EXAMINE_DRAGONS_WITHOUT_OWL, 0); | |
2462 | ||
2463 | attack_code = owl_attack(str, &attack_point, NULL, NULL); | |
2464 | ||
2465 | if (attack_code == 0) { | |
2466 | /* The owl code claims there is no attack. We test this by | |
2467 | * trying to attack on all empty spaces in the eyeshape. | |
2468 | */ | |
2469 | for (k = 0; k < eyesize; k++) { | |
2470 | if (board[eye_vertices[k]] == EMPTY | |
2471 | && is_legal(eye_vertices[k], BLACK) | |
2472 | && owl_does_attack(eye_vertices[k], str, NULL)) { | |
2473 | gprintf("%1m alive, but %1m attacks:\n", str, eye_vertices[k]); | |
2474 | showboard(0); | |
2475 | gprintf("\n"); | |
2476 | } | |
2477 | } | |
2478 | ||
2479 | /* Furthermore, if the eyespace is almost filled, white should | |
2480 | * be able to play on the remaining eyespace point and still be | |
2481 | * alive. | |
2482 | */ | |
2483 | if (internal_stones == eyesize - 1) { | |
2484 | for (k = 0; k < eyesize; k++) { | |
2485 | if (board[eye_vertices[k]] == EMPTY | |
2486 | && !owl_does_defend(eye_vertices[k], str, NULL)) { | |
2487 | gprintf("%1m alive, but almost filled with nakade:\n", str); | |
2488 | showboard(0); | |
2489 | } | |
2490 | } | |
2491 | } | |
2492 | } | |
2493 | else { | |
2494 | defense_code = owl_defend(str, &defense_point, NULL, NULL); | |
2495 | if (defense_code == 0) { | |
2496 | /* The owl code claims there is no defense. We test this by | |
2497 | * trying to defend on all empty spaces in the eyeshape. | |
2498 | */ | |
2499 | for (k = 0; k < eyesize; k++) { | |
2500 | if (board[eye_vertices[k]] == EMPTY | |
2501 | && is_legal(eye_vertices[k], WHITE) | |
2502 | && owl_does_defend(eye_vertices[k], str, NULL)) { | |
2503 | gprintf("%1m dead, but %1m defends:\n", str, eye_vertices[k]); | |
2504 | showboard(0); | |
2505 | gprintf("\n"); | |
2506 | } | |
2507 | } | |
2508 | } | |
2509 | else { | |
2510 | /* The owl code claims the dragon is critical. Verify the | |
2511 | * attack and defense points. | |
2512 | */ | |
2513 | if (board[attack_point] != EMPTY | |
2514 | || !is_legal(attack_point, BLACK)) { | |
2515 | gprintf("Bad attack point %1m:\n", attack_point); | |
2516 | showboard(0); | |
2517 | } | |
2518 | else if (!owl_does_attack(attack_point, str, NULL)) { | |
2519 | gprintf("Attack point %1m failed:\n", attack_point); | |
2520 | showboard(0); | |
2521 | } | |
2522 | ||
2523 | if (board[defense_point] != EMPTY | |
2524 | || !is_legal(defense_point, WHITE)) { | |
2525 | gprintf("Bad defense point %1m:\n", defense_point); | |
2526 | showboard(0); | |
2527 | } | |
2528 | else if (!owl_does_defend(defense_point, str, NULL)) { | |
2529 | gprintf("Defense point %1m failed:\n", defense_point); | |
2530 | showboard(0); | |
2531 | } | |
2532 | } | |
2533 | } | |
2534 | } | |
2535 | verbose = save_verbose; | |
2536 | } | |
2537 | ||
2538 | /******************************************************************** | |
2539 | * The following static functions are helpers for analyze_eyegraph() | |
2540 | * further down. The purpose is to evaluate eye graphs according to | |
2541 | * the rules for local games, as described in doc/eyes.texi. | |
2542 | * | |
2543 | * The technique to do this is to convert the eye evaluation problem | |
2544 | * into a tactical style life and death reading problem. Tactical in | |
2545 | * the sense of needing to decide whether certain stones can be | |
2546 | * captured, but not in the sense of the tactical reading that five | |
2547 | * liberties are considered safe. | |
2548 | * | |
2549 | * We illustrate how this works with an example. Consider the eye shape | |
2550 | * | |
2551 | * ! | |
2552 | * .X | |
2553 | * !... | |
2554 | * | |
2555 | * The basic idea is to embed the eyespace in a perfectly connected | |
2556 | * group without additional eyes or eye potential. This is most easily | |
2557 | * done by the somewhat brutal trick to fill the entire board with | |
2558 | * stones. We let the group consist of white stones (O) and get this | |
2559 | * result, disregarding the two marginal eye vertices: | |
2560 | * | |
2561 | * A B C D E F G H J K L M N O P Q R S T | |
2562 | * 19 O O O O O O O O O O O O O O O O O O O 19 | |
2563 | * 18 O O O O O O O O O O O O O O O O O O O 18 | |
2564 | * 17 O O O O O O O O O O O O O O O O O O O 17 | |
2565 | * 16 O O O O O O O O O O O O O O O O O O O 16 | |
2566 | * 15 O O O O O O O O O O O O O O O O O O O 15 | |
2567 | * 14 O O O O O O O O O O O O O O O O O O O 14 | |
2568 | * 13 O O O O O O O O O O O O O O O O O O O 13 | |
2569 | * 12 O O O O O O O O . O O O O O O O O O O 12 | |
2570 | * 11 O O O O O O O . X O O O O O O O O O O 11 | |
2571 | * 10 O O O O O O . . . . O O O O O O O O O 10 | |
2572 | * 9 O O O O O O O O O O O O O O O O O O O 9 | |
2573 | * 8 O O O O O O O O O O O O O O O O O O O 8 | |
2574 | * 7 O O O O O O O O O O O O O O O O O O O 7 | |
2575 | * 6 O O O O O O O O O O O O O O O O O O O 6 | |
2576 | * 5 O O O O O O O O O O O O O O O O O O O 5 | |
2577 | * 4 O O O O O O O O O O O O O O O O O O O 4 | |
2578 | * 3 O O O O O O O O O O O O O O O O O O O 3 | |
2579 | * 2 O O O O O O O O O O O O O O O O O O O 2 | |
2580 | * 1 O O O O O O O O O O O O O O O O O O O 1 | |
2581 | * A B C D E F G H J K L M N O P Q R S T | |
2582 | * | |
2583 | * The question now is whether black can capture all the white stones | |
2584 | * under alternating play where only white may pass. However, first we | |
2585 | * need to make the top and leftmost eye vertices marginal. This is | |
2586 | * done by inserting small invincible black groups in the sea of white | |
2587 | * stones, in contact with the marginal vertices. | |
2588 | * | |
2589 | * A B C D E F G H J K L M N O P Q R S T | |
2590 | * 19 . O O O O O O O O O O O O O O O O O O 19 | |
2591 | * 18 O O O O O O O O X X X O O O O O O O O 18 | |
2592 | * 17 O O O O O O O O X . X O O O O O O O O 17 | |
2593 | * 16 O O O O O O O O X X X O O O O O O O O 16 | |
2594 | * 15 O O O O O O O O X . X O O O O O O O O 15 | |
2595 | * 14 O O O O O O O O X X X O O O O O O O O 14 | |
2596 | * 13 O O O O O O O O X O O O O O O O O O O 13 | |
2597 | * 12 O O O O O O O O . O O O O O O O O O O 12 | |
2598 | * 11 O O O O O O O . X O O O O O O O O O O 11 | |
2599 | * 10 O O O O O O . . . . O O O O O O O O O 10 | |
2600 | * 9 O O O O O O X O O O O O O O O O O O O 9 | |
2601 | * 8 O O O O X X X O O O O O O O O O O O O 8 | |
2602 | * 7 O O O O X . X O O O O O O O O O O O O 7 | |
2603 | * 6 O O O O X X X O O O O O O O O O O O O 6 | |
2604 | * 5 O O O O X . X O O O O O O O O O O O O 5 | |
2605 | * 4 . O O O X X X O O O O O O O O O O O O 4 | |
2606 | * 3 X X . O O O O O O O O O O O O O O O O 3 | |
2607 | * 2 X . X O O O O O O O O O O O O O O O O 2 | |
2608 | * 1 . X X O O O O O O O O O O O O O O O O 1 | |
2609 | * A B C D E F G H J K L M N O P Q R S T | |
2610 | * | |
2611 | * In this diagram we have also added an invincible black group in the | |
2612 | * lower left corner in order to add two outer liberties (at A4 and | |
2613 | * C3) for the white group (this is sometimes needed for the tactical | |
2614 | * life and death reading to make sense). Furthermore there is an | |
2615 | * extra eye at A19. This is used when we want to distinguish between | |
2616 | * 0 and 1 (or 2) eyes since the tactical life and death reading by | |
2617 | * itself only cares about two eyes or not. When trying to distinguish | |
2618 | * between 1 (or 0) and 2 eyes we first fill in A19 again. | |
2619 | * | |
2620 | * Depending on the tactical life and death status with or without the | |
2621 | * extra eye we can determine the number of eyes. By evaluating | |
2622 | * tactical life and death status after having made a move we can also | |
2623 | * identify ko threats and critical moves. | |
2624 | * | |
2625 | * This code is organized as follows: | |
2626 | * | |
2627 | * analyze_eyegraph() converts the eyegraph into the tactical board | |
2628 | * position as demonstrated, then calls evaluate_eyespace() to its eye | |
2629 | * value. | |
2630 | * | |
2631 | * white_area() is a helper to add a small invincible black group on | |
2632 | * the board. | |
2633 | * | |
2634 | * evaluate_eyespace() calls tactical_life() and itself recursively to | |
2635 | * determine the eye value and the critical points. | |
2636 | * | |
2637 | * tactical_life() determines whether the white stones on the board | |
2638 | * (assumed to be a single string) can be captured under alternating | |
2639 | * play. | |
2640 | * | |
2641 | * tactical_life_attack() and tactical_life_defend() are two mutually | |
2642 | * recursive functions which perform the actual reading for | |
2643 | * tactical_life(). | |
2644 | * | |
2645 | * Worth to mention in this overview is also the cache used for | |
2646 | * tactical_life_attack() and tactical_life_defend(). Since we have a | |
2647 | * limited number of vertices (eye space points + two outer liberties | |
2648 | * + possibly an extra eye) to play on we use a complete cache with a | |
2649 | * unique entry for every possible configuration of stones on the | |
2650 | * considered vertices. | |
2651 | * | |
2652 | * For each cache entry four bits are used, two for attack results and | |
2653 | * two four defense results. Each of these can take the values 0-3 | |
2654 | * with the following interpretations: | |
2655 | * 0 - not yet considered | |
2656 | * 1 - result is being computed | |
2657 | * 2 - result has been computed and was a failure (0) | |
2658 | * 3 - result has been computed and was a success (1) | |
2659 | */ | |
2660 | ||
2661 | /* Like trymove() except that it does a superko check. This does, | |
2662 | * however, only disallow repetition (besides simple ko) if the move | |
2663 | * does not capture any stones. | |
2664 | */ | |
2665 | static int | |
2666 | eyegraph_trymove(int pos, int color, const char *message, int str) | |
2667 | { | |
2668 | static Hash_data remembered_board_hashes[MAXSTACK]; | |
2669 | int k; | |
2670 | int does_capture = does_capture_something(pos, color); | |
2671 | ||
2672 | remembered_board_hashes[stackp] = board_hash; | |
2673 | ||
2674 | if (!trymove(pos, color, message, str)) | |
2675 | return 0; | |
2676 | ||
2677 | if (does_capture) | |
2678 | return 1; | |
2679 | ||
2680 | for (k = 0; k < stackp; k++) | |
2681 | if (hashdata_is_equal(board_hash, remembered_board_hashes[k])) { | |
2682 | popgo(); | |
2683 | return 0; | |
2684 | } | |
2685 | ||
2686 | return 1; | |
2687 | } | |
2688 | ||
2689 | static int | |
2690 | eyegraph_is_margin_or_outer_liberty(int vertex) | |
2691 | { | |
2692 | int k; | |
2693 | int r; | |
2694 | int num_libs; | |
2695 | int libs[MAXLIBS]; | |
2696 | int eyes; | |
2697 | ||
2698 | for (k = 0; k < 4; k++) { | |
2699 | if (board[vertex + delta[k]] == BLACK) { | |
2700 | eyes = 0; | |
2701 | num_libs = findlib(vertex + delta[k], MAXLIBS, libs); | |
2702 | ||
2703 | for (r = 0; r < num_libs; r++) | |
2704 | if (is_suicide(libs[r], WHITE)) | |
2705 | eyes++; | |
2706 | ||
2707 | if (eyes >= 2) | |
2708 | return 1; | |
2709 | } | |
2710 | } | |
2711 | return 0; | |
2712 | } | |
2713 | ||
2714 | static int | |
2715 | eyegraph_order_moves(int num_vertices, int *vertices, int color_to_move, int *moves) | |
2716 | { | |
2717 | int num_moves = 0; | |
2718 | int scores[BOARDMAX]; | |
2719 | int move; | |
2720 | int score; | |
2721 | int k; | |
2722 | int r; | |
2723 | ||
2724 | for (k = 0; k < num_vertices; k++) { | |
2725 | if (k >= num_vertices - 3) { | |
2726 | /* Never useful for white to fill in outer liberties or a second eye. */ | |
2727 | if (color_to_move == WHITE) | |
2728 | break; | |
2729 | /* No use playing the second outer liberty before the first one. */ | |
2730 | if (k == num_vertices - 2 && board[vertices[num_vertices - 3]] == EMPTY) | |
2731 | continue; | |
2732 | } | |
2733 | ||
2734 | move = vertices[k]; | |
2735 | score = 0; | |
2736 | ||
2737 | if (board[move] != EMPTY) | |
2738 | continue; | |
2739 | ||
2740 | if (eyegraph_is_margin_or_outer_liberty(move)) { | |
2741 | if (k < num_vertices - 3) | |
2742 | score = 5; /* margin */ | |
2743 | else | |
2744 | score = -10; /* outer liberty */ | |
2745 | } | |
2746 | ||
2747 | if (accuratelib(move, color_to_move, 2, NULL) == 1) | |
2748 | score -= 3; | |
2749 | ||
2750 | for (r = 0; r < 4; r++) { | |
2751 | if (board[move + delta[r]] == EMPTY) | |
2752 | score += 2; | |
2753 | else if (board[move + delta[r]] == BLACK) | |
2754 | score += 3; | |
2755 | } | |
2756 | ||
2757 | moves[num_moves] = move; | |
2758 | scores[num_moves] = score; | |
2759 | num_moves++; | |
2760 | } | |
2761 | ||
2762 | for (k = 0; k < num_moves; k++) { | |
2763 | int maxscore = scores[k]; | |
2764 | int max_at = 0; | |
2765 | ||
2766 | /* Find the move with the biggest score. */ | |
2767 | for (r = k + 1; r < num_moves; r++) { | |
2768 | if (scores[r] > maxscore) { | |
2769 | maxscore = scores[r]; | |
2770 | max_at = r; | |
2771 | } | |
2772 | } | |
2773 | ||
2774 | /* Now exchange the move at k with the move at max_at. | |
2775 | * Don't forget to exchange the scores as well. | |
2776 | */ | |
2777 | if (max_at != 0) { | |
2778 | int temp = moves[max_at]; | |
2779 | moves[max_at] = moves[k]; | |
2780 | moves[k] = temp; | |
2781 | temp = scores[max_at]; | |
2782 | scores[max_at] = scores[k]; | |
2783 | scores[k] = temp; | |
2784 | } | |
2785 | } | |
2786 | ||
2787 | return num_moves; | |
2788 | } | |
2789 | ||
2790 | /* Place a small invincible black group on the board. | |
2791 | * It is required that previously there were white stones at all | |
2792 | * involved vertices and on the surrounding vertices. | |
2793 | * | |
2794 | * Returns 1 if a group was placed, 0 otherwise. | |
2795 | */ | |
2796 | static int | |
2797 | white_area(int mx[BOARDMAX], int pos, int up, int right, int marginpos, | |
2798 | int distance) | |
2799 | { | |
2800 | int u, v; | |
2801 | int k; | |
2802 | int edge = is_edge_vertex(marginpos); | |
2803 | ||
2804 | for (k = 1; k < distance; k++) | |
2805 | if (!ON_BOARD(marginpos + k * up) | |
2806 | || mx[marginpos + k * up] != WHITE) | |
2807 | return 0; | |
2808 | ||
2809 | for (u = -1; u <= 4; u++) | |
2810 | for (v = -1; v <= 4; v++) { | |
2811 | int pos2 = pos + u * up + v * right; | |
2812 | if (!ON_BOARD(pos2)) { | |
2813 | if (!edge) | |
2814 | return 0; | |
2815 | else if (u >= 0 && u <= 3 && v >= 0 && v <= 3) | |
2816 | return 0; | |
2817 | else if (I(pos2) != I(NORTH(marginpos)) | |
2818 | && I(pos2) != I(SOUTH(marginpos)) | |
2819 | && J(pos2) != J(WEST(marginpos)) | |
2820 | && J(pos2) != J(EAST(marginpos))) | |
2821 | return 0; | |
2822 | } | |
2823 | else if (mx[pos2] != WHITE) | |
2824 | return 0; | |
2825 | } | |
2826 | ||
2827 | for (u = 0; u <= 3; u++) | |
2828 | for (v = 0; v <= 3; v++) { | |
2829 | int pos2 = pos + u * up + v * right; | |
2830 | mx[pos2] = BLACK; | |
2831 | } | |
2832 | ||
2833 | mx[pos + up + right] = EMPTY; | |
2834 | mx[pos + 2 * up + 2 * right] = EMPTY; | |
2835 | ||
2836 | return 1; | |
2837 | } | |
2838 | ||
2839 | ||
2840 | #define EYEGRAPH_RETURN(result, trace) \ | |
2841 | do { \ | |
2842 | if (sgf_dumptree) \ | |
2843 | sgftreeAddComment(sgf_dumptree, (trace)); \ | |
2844 | return (result); \ | |
2845 | } while (0); | |
2846 | ||
2847 | static int tactical_life_defend(int str, int num_vertices, int *vertices, | |
2848 | unsigned char *results); | |
2849 | ||
2850 | /* Determine whether black can capture all white stones. */ | |
2851 | static int | |
2852 | tactical_life_attack(int str, int num_vertices, int *vertices, | |
2853 | unsigned char *results) | |
2854 | { | |
2855 | int k; | |
2856 | int hash = 0; | |
2857 | int cached_result; | |
2858 | int result; | |
2859 | int num_moves; | |
2860 | int moves[BOARDMAX]; | |
2861 | ||
2862 | /* Compute hash value to index the result cache with. */ | |
2863 | for (k = 0; k < num_vertices; k++) { | |
2864 | hash *= 3; | |
2865 | hash += board[vertices[k]]; | |
2866 | } | |
2867 | hash *= 2; | |
2868 | hash += (board_ko_pos != NO_MOVE); | |
2869 | ||
2870 | /* Is the result known from the cache? */ | |
2871 | cached_result = results[hash] & 3; | |
2872 | ||
2873 | if (0) { | |
2874 | showboard(0); | |
2875 | gprintf("%d %d (%d)\n", hash, cached_result, results[hash]); | |
2876 | } | |
2877 | ||
2878 | if (cached_result == 2) | |
2879 | EYEGRAPH_RETURN(0, "tactical_life_attack: 0 (cached)"); | |
2880 | if (cached_result == 3) | |
2881 | EYEGRAPH_RETURN(1, "tactical_life_attack: win (cached)"); | |
2882 | if (cached_result == 1) | |
2883 | EYEGRAPH_RETURN(1, "tactical_life_attack: win (open node in cache)"); | |
2884 | ||
2885 | /* Mark this entry in the cache as currently being computed. */ | |
2886 | results[hash] |= 1; | |
2887 | ||
2888 | /* Try to play on all relevant vertices. */ | |
2889 | num_moves = eyegraph_order_moves(num_vertices, vertices, | |
2890 | OTHER_COLOR(board[str]), moves); | |
2891 | for (k = 0; k < num_moves; k++) { | |
2892 | int move = moves[k]; | |
2893 | if (eyegraph_trymove(move, OTHER_COLOR(board[str]), | |
2894 | "tactical_life_attack", str)) { | |
2895 | /* We were successful if the white stones were captured or if no | |
2896 | * defense can be found. | |
2897 | */ | |
2898 | if (board[str] == EMPTY) | |
2899 | result = 1; | |
2900 | else | |
2901 | result = !tactical_life_defend(str, num_vertices, vertices, results); | |
2902 | ||
2903 | popgo(); | |
2904 | ||
2905 | if (result == 1) { | |
2906 | /* Store the result (success) in the cache. */ | |
2907 | results[hash] = (results[hash] & (~3)) | 3; | |
2908 | EYEGRAPH_RETURN(1, "tactical_life_attack: win"); | |
2909 | } | |
2910 | } | |
2911 | } | |
2912 | ||
2913 | /* Store the result (failure) in the cache. */ | |
2914 | results[hash] = (results[hash] & (~3)) | 2; | |
2915 | EYEGRAPH_RETURN(0, "tactical_life_attack: 0"); | |
2916 | } | |
2917 | ||
2918 | /* Determine whether white can live with all stones. */ | |
2919 | static int | |
2920 | tactical_life_defend(int str, int num_vertices, int *vertices, | |
2921 | unsigned char *results) | |
2922 | { | |
2923 | int k; | |
2924 | int hash = 0; | |
2925 | int cached_result; | |
2926 | int result; | |
2927 | int num_moves; | |
2928 | int moves[BOARDMAX]; | |
2929 | ||
2930 | /* Compute hash value to index the result cache with. */ | |
2931 | for (k = 0; k < num_vertices; k++) { | |
2932 | hash *= 3; | |
2933 | ASSERT1(board[vertices[k]] <= 2, vertices[k]); | |
2934 | hash += board[vertices[k]]; | |
2935 | } | |
2936 | hash *= 2; | |
2937 | hash += (board_ko_pos != NO_MOVE); | |
2938 | ||
2939 | /* Is the result known from the cache? */ | |
2940 | cached_result = (results[hash] >> 2) & 3; | |
2941 | ||
2942 | if (0) { | |
2943 | showboard(0); | |
2944 | gprintf("%d %d (%d)\n", hash, cached_result, results[hash]); | |
2945 | } | |
2946 | ||
2947 | if (cached_result == 2) | |
2948 | EYEGRAPH_RETURN(0, "tactical_life_defend: 0 (cached)"); | |
2949 | if (cached_result == 3) | |
2950 | EYEGRAPH_RETURN(1, "tactical_life_defend: win (cached)"); | |
2951 | if (cached_result == 1) | |
2952 | EYEGRAPH_RETURN(1, "tactical_life_defend: win (node open in cache)"); | |
2953 | ||
2954 | /* Mark this entry in the cache as currently being computed. */ | |
2955 | results[hash] |= (1 << 2); | |
2956 | ||
2957 | /* Try to play on all relevant vertices. */ | |
2958 | num_moves = eyegraph_order_moves(num_vertices, vertices, board[str], moves); | |
2959 | for (k = 0; k < num_moves; k++) { | |
2960 | int move = moves[k]; | |
2961 | if ((!is_suicide(move, OTHER_COLOR(board[str])) | |
2962 | || does_capture_something(move, board[str])) | |
2963 | && eyegraph_trymove(move, board[str], "tactical_life_defend", str)) { | |
2964 | /* We were successful if no attack can be found. */ | |
2965 | result = !tactical_life_attack(str, num_vertices, vertices, results); | |
2966 | ||
2967 | popgo(); | |
2968 | ||
2969 | if (result == 1) { | |
2970 | /* Store the result (success) in the cache. */ | |
2971 | results[hash] = (results[hash] & (~12)) | (3 << 2); | |
2972 | EYEGRAPH_RETURN(1, "tactical_life_defend: win"); | |
2973 | } | |
2974 | } | |
2975 | } | |
2976 | ||
2977 | /* If no move worked, also try passing. */ | |
2978 | if (!tactical_life_attack(str, num_vertices, vertices, results)) { | |
2979 | /* Store the result (success) in the cache. */ | |
2980 | results[hash] = (results[hash] & (~12)) | (3 << 2); | |
2981 | EYEGRAPH_RETURN(1, "tactical_life_defend: win"); | |
2982 | } | |
2983 | ||
2984 | /* Store the result (failure) in the cache. */ | |
2985 | results[hash] = (results[hash] & (~12)) | (2 << 2); | |
2986 | EYEGRAPH_RETURN(0, "tactical_life_defend: 0"); | |
2987 | } | |
2988 | ||
2989 | /* Determine the tactical life and death status of all white stones. | |
2990 | * Also find all attack and defense moves. The parameter have_eye | |
2991 | * determines whether the extra eye in the upper left corner should be | |
2992 | * used or filled in before starting reading. | |
2993 | */ | |
2994 | static void | |
2995 | tactical_life(int have_eye, int num_vertices, int *vertices, | |
2996 | int *attack_code, int *num_attacks, int *attack_points, | |
2997 | int *defense_code, int *num_defenses, int *defense_points, | |
2998 | unsigned char *results) | |
2999 | { | |
3000 | int k; | |
3001 | int str; | |
3002 | int num_moves; | |
3003 | int moves[BOARDMAX]; | |
3004 | ||
3005 | gg_assert(attack_code != NULL && defense_code != NULL); | |
3006 | ||
3007 | /* We know that the large white group includes A18. This is the | |
3008 | * vertex we test to determine whether the white stones have been | |
3009 | * captured. | |
3010 | */ | |
3011 | str = POS(1, 0); | |
3012 | ||
3013 | if (board[str] == EMPTY) { | |
3014 | /* The stones have already been captured, too late to defend. */ | |
3015 | *attack_code = WIN; | |
3016 | *defense_code = 0; | |
3017 | return; | |
3018 | } | |
3019 | ||
3020 | /* Fill in the extra eye if have_eye is 0. If filling in would be | |
3021 | * suicide the white stones can be considered dead. | |
3022 | */ | |
3023 | if (!have_eye) { | |
3024 | if (!eyegraph_trymove(POS(0, 0), WHITE, "tactical_life-A", NO_MOVE)) { | |
3025 | *attack_code = WIN; | |
3026 | *defense_code = 0; | |
3027 | return; | |
3028 | } | |
3029 | } | |
3030 | ||
3031 | *attack_code = 0; | |
3032 | *defense_code = 0; | |
3033 | ||
3034 | /* Call tactical_life_attack() and tactical_life_defend() to | |
3035 | * determine status. | |
3036 | */ | |
3037 | if (tactical_life_attack(str, num_vertices, vertices, results)) { | |
3038 | *attack_code = WIN; | |
3039 | if (tactical_life_defend(str, num_vertices, vertices, results)) | |
3040 | *defense_code = WIN; | |
3041 | } | |
3042 | else | |
3043 | *defense_code = WIN; | |
3044 | ||
3045 | ||
3046 | /* If the status is critical, try to play at each relevant vertex | |
3047 | * and call tactical_life_defend() or tactical_life_attack() to | |
3048 | * determine whether the move works as attack or defense. | |
3049 | */ | |
3050 | if (*attack_code != 0 && *defense_code != 0) { | |
3051 | if (num_attacks != NULL && attack_points != NULL) { | |
3052 | *num_attacks = 0; | |
3053 | num_moves = eyegraph_order_moves(num_vertices, vertices, | |
3054 | OTHER_COLOR(board[str]), moves); | |
3055 | for (k = 0; k < num_moves; k++) { | |
3056 | int move = moves[k]; | |
3057 | if (eyegraph_trymove(move, OTHER_COLOR(board[str]), "tactical_life-B", | |
3058 | str)) { | |
3059 | if (board[str] == EMPTY | |
3060 | || !tactical_life_defend(str, num_vertices, vertices, results)) | |
3061 | attack_points[(*num_attacks)++] = move; | |
3062 | popgo(); | |
3063 | } | |
3064 | } | |
3065 | } | |
3066 | ||
3067 | if (num_defenses != NULL && defense_points != NULL) { | |
3068 | *num_defenses = 0; | |
3069 | num_moves = eyegraph_order_moves(num_vertices, vertices, board[str], | |
3070 | moves); | |
3071 | for (k = 0; k < num_moves; k++) { | |
3072 | int move = moves[k]; | |
3073 | if (eyegraph_trymove(move, board[str], "tactical_life-C", str)) { | |
3074 | if (!tactical_life_attack(str, num_vertices, vertices, results)) | |
3075 | defense_points[(*num_defenses)++] = move; | |
3076 | popgo(); | |
3077 | } | |
3078 | } | |
3079 | } | |
3080 | } | |
3081 | ||
3082 | /* Unfill the extra eye if we didn't use it. */ | |
3083 | if (!have_eye) | |
3084 | popgo(); | |
3085 | } | |
3086 | ||
3087 | /* Determine the eye value of the eyespace for the big white group on | |
3088 | * the board and vital moves. The possible eye values are documented | |
3089 | * in the preamble to eyes.db. By calling tactical_life() multiple | |
3090 | * times, with and without using an extra eye, we can compute the eye | |
3091 | * values. To determine ko threats and vital moves, tactical_life() is | |
3092 | * called again after trying to play on one of the relevant vertices. | |
3093 | * In order to find out whether ko threats really are effective and to | |
3094 | * distinguish between 0122/1122 and 0012/0011 eye values (see | |
3095 | * discussion on pattern 6141 in the preamble of eyes.db), we may also | |
3096 | * need to recursively call ourselves after a move has been made. | |
3097 | */ | |
3098 | static void | |
3099 | evaluate_eyespace(struct eyevalue *result, int num_vertices, int *vertices, | |
3100 | int *num_vital_attacks, int *vital_attacks, | |
3101 | int *num_vital_defenses, int *vital_defenses, | |
3102 | unsigned char *tactical_life_results) | |
3103 | { | |
3104 | int k; | |
3105 | int attack_code; | |
3106 | int num_attacks; | |
3107 | int attack_points[BOARDMAX]; | |
3108 | int defense_code; | |
3109 | int num_defenses; | |
3110 | int defense_points[BOARDMAX]; | |
3111 | int attack_code2; | |
3112 | int num_attacks2; | |
3113 | int attack_points2[BOARDMAX]; | |
3114 | int defense_code2; | |
3115 | struct eyevalue result2; | |
3116 | int num_vital_attacks2; | |
3117 | int vital_attacks2[BOARDMAX]; | |
3118 | int num_vital_defenses2; | |
3119 | int vital_defenses2[BOARDMAX]; | |
3120 | int num_moves; | |
3121 | int moves[BOARDMAX]; | |
3122 | ||
3123 | *num_vital_attacks = 0; | |
3124 | *num_vital_defenses = 0; | |
3125 | ||
3126 | /* Determine tactical life without an extra eye. */ | |
3127 | tactical_life(0, num_vertices, vertices, | |
3128 | &attack_code, &num_attacks, attack_points, | |
3129 | &defense_code, &num_defenses, defense_points, | |
3130 | tactical_life_results); | |
3131 | ||
3132 | if (attack_code == 0) { | |
3133 | /* Alive without extra eye. | |
3134 | * Possible results: 0222, 1222, 2222 | |
3135 | * | |
3136 | * Determine whether there are ko threats and how serious. | |
3137 | */ | |
3138 | int a = 2; | |
3139 | ||
3140 | if (sgf_dumptree) | |
3141 | sgftreeAddComment(sgf_dumptree, "Alive without extra eye.\n"); | |
3142 | ||
3143 | num_moves = eyegraph_order_moves(num_vertices, vertices, BLACK, moves); | |
3144 | for (k = 0; k < num_moves; k++) { | |
3145 | int acode, dcode; | |
3146 | int move = moves[k]; | |
3147 | if (eyegraph_trymove(move, BLACK, "evaluate_eyespace-A", NO_MOVE)) { | |
3148 | tactical_life(0, num_vertices, vertices, &acode, NULL, NULL, | |
3149 | &dcode, NULL, NULL, tactical_life_results); | |
3150 | if (acode != 0) { | |
3151 | tactical_life(1, num_vertices, vertices, &acode, NULL, NULL, | |
3152 | &dcode, NULL, NULL, tactical_life_results); | |
3153 | if (acode != 0) { | |
3154 | if (a == 1) | |
3155 | *num_vital_attacks = 0; | |
3156 | a = 0; | |
3157 | vital_attacks[(*num_vital_attacks)++] = move; | |
3158 | if (sgf_dumptree) | |
3159 | sgftreeAddComment(sgf_dumptree, | |
3160 | "Ko threat to remove both eyes.\n"); | |
3161 | } | |
3162 | else { | |
3163 | if (a != 0) { | |
3164 | vital_attacks[(*num_vital_attacks)++] = move; | |
3165 | a = 1; | |
3166 | } | |
3167 | if (sgf_dumptree) | |
3168 | sgftreeAddComment(sgf_dumptree, "Ko threat to remove one eye.\n"); | |
3169 | } | |
3170 | } | |
3171 | popgo(); | |
3172 | } | |
3173 | } | |
3174 | set_eyevalue(result, a, 2, 2, 2); | |
3175 | if (sgf_dumptree) { | |
3176 | if (a == 0) | |
3177 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0222.\n"); | |
3178 | else if (a == 1) | |
3179 | sgftreeAddComment(sgf_dumptree, "Eyevalue 1222.\n"); | |
3180 | else | |
3181 | sgftreeAddComment(sgf_dumptree, "Eyevalue 2222.\n"); | |
3182 | } | |
3183 | } | |
3184 | else if (defense_code != 0) { | |
3185 | /* Critical without extra eye. | |
3186 | * Possible results: 0022, 0122, 1122 | |
3187 | */ | |
3188 | if (sgf_dumptree) | |
3189 | sgftreeAddComment(sgf_dumptree, "Critical without extra eye.\n"); | |
3190 | tactical_life(1, num_vertices, vertices, | |
3191 | &attack_code2, &num_attacks2, attack_points2, | |
3192 | &defense_code2, NULL, NULL, tactical_life_results); | |
3193 | for (k = 0; k < num_defenses; k++) | |
3194 | vital_defenses[(*num_vital_defenses)++] = defense_points[k]; | |
3195 | if (attack_code2 == WIN) { | |
3196 | /* A chimera. 0022. */ | |
3197 | set_eyevalue(result, 0, 0, 2, 2); | |
3198 | for (k = 0; k < num_attacks2; k++) | |
3199 | vital_attacks[(*num_vital_attacks)++] = attack_points2[k]; | |
3200 | if (sgf_dumptree) | |
3201 | sgftreeAddComment(sgf_dumptree, "Eyevalue: 0022.\n"); | |
3202 | } | |
3203 | else { | |
3204 | int a = 1; | |
3205 | for (k = 0; k < num_attacks; k++) { | |
3206 | int move = attack_points[k]; | |
3207 | if (eyegraph_trymove(move, BLACK, "evaluate_eyespace-B", NO_MOVE)) { | |
3208 | evaluate_eyespace(&result2, num_vertices, vertices, | |
3209 | &num_vital_attacks2, vital_attacks2, | |
3210 | &num_vital_defenses2, vital_defenses2, | |
3211 | tactical_life_results); | |
3212 | /* If result2 is 0011 for some move we have 0122 as final | |
3213 | * result, otherwise 1122. | |
3214 | */ | |
3215 | if (min_eyes(&result2) == 0 | |
3216 | && max_eyes(&result2) == 1 | |
3217 | && max_eye_threat(&result2) == 1) { | |
3218 | if (a == 1) | |
3219 | *num_vital_attacks = 0; | |
3220 | a = 0; | |
3221 | vital_attacks[(*num_vital_attacks)++] = move; | |
3222 | } | |
3223 | else if (a == 1) | |
3224 | vital_attacks[(*num_vital_attacks)++] = move; | |
3225 | popgo(); | |
3226 | } | |
3227 | } | |
3228 | set_eyevalue(result, a, 1, 2, 2); | |
3229 | if (sgf_dumptree) { | |
3230 | if (a == 0) | |
3231 | sgftreeAddComment(sgf_dumptree, "Eyevalue: 0122.\n"); | |
3232 | else | |
3233 | sgftreeAddComment(sgf_dumptree, "Eyevalue: 1122.\n"); | |
3234 | } | |
3235 | } | |
3236 | } | |
3237 | else { | |
3238 | /* Dead without extra eye. | |
3239 | * Possible results: 0000, 0001, 0002, 0011, 0012, 0111, 0112, 1111, 1112 | |
3240 | * | |
3241 | * Now determine tactical life with an extra eye. | |
3242 | */ | |
3243 | if (sgf_dumptree) | |
3244 | sgftreeAddComment(sgf_dumptree, "Dead without extra eye.\n"); | |
3245 | tactical_life(1, num_vertices, vertices, | |
3246 | &attack_code, &num_attacks, attack_points, | |
3247 | &defense_code, &num_defenses, defense_points, | |
3248 | tactical_life_results); | |
3249 | if (attack_code == 0) { | |
3250 | /* Alive with extra eye. | |
3251 | * Possible results: 0111, 0112, 1111, 1112 | |
3252 | */ | |
3253 | int a = 1; | |
3254 | int d = 1; | |
3255 | if (sgf_dumptree) | |
3256 | sgftreeAddComment(sgf_dumptree, "Alive with extra eye.\n"); | |
3257 | num_moves = eyegraph_order_moves(num_vertices, vertices, BLACK, moves); | |
3258 | for (k = 0; k < num_moves; k++) { | |
3259 | int acode, dcode; | |
3260 | int move = moves[k]; | |
3261 | if (eyegraph_trymove(move, BLACK, "evaluate_eyespace-C", NO_MOVE)) { | |
3262 | tactical_life(1, num_vertices, vertices, &acode, NULL, NULL, | |
3263 | &dcode, NULL, NULL, tactical_life_results); | |
3264 | if (acode != 0) { | |
3265 | evaluate_eyespace(&result2, num_vertices, vertices, | |
3266 | &num_vital_attacks2, vital_attacks2, | |
3267 | &num_vital_defenses2, vital_defenses2, | |
3268 | tactical_life_results); | |
3269 | /* This is either 0011 or 0012. Only the first is acceptable. */ | |
3270 | if (max_eye_threat(&result2) == 1) { | |
3271 | vital_attacks[(*num_vital_attacks)++] = move; | |
3272 | a = 0; | |
3273 | if (sgf_dumptree) | |
3274 | sgftreeAddComment(sgf_dumptree, "Attacking ko threat.\n"); | |
3275 | } | |
3276 | } | |
3277 | popgo(); | |
3278 | } | |
3279 | } | |
3280 | ||
3281 | num_moves = eyegraph_order_moves(num_vertices, vertices, WHITE, moves); | |
3282 | for (k = 0; k < num_moves; k++) { | |
3283 | int acode, dcode; | |
3284 | int move = moves[k]; | |
3285 | if (eyegraph_trymove(move, WHITE, "evaluate_eyespace-D", NO_MOVE)) { | |
3286 | tactical_life(0, num_vertices, vertices, &acode, NULL, NULL, | |
3287 | &dcode, NULL, NULL, tactical_life_results); | |
3288 | if (dcode != 0) { | |
3289 | evaluate_eyespace(&result2, num_vertices, vertices, | |
3290 | &num_vital_attacks2, vital_attacks2, | |
3291 | &num_vital_defenses2, vital_defenses2, | |
3292 | tactical_life_results); | |
3293 | /* This is either 1122 or 0122. Only the first is acceptable. */ | |
3294 | if (min_eye_threat(&result2) == 1) { | |
3295 | vital_defenses[(*num_vital_defenses)++] = move; | |
3296 | d = 2; | |
3297 | if (sgf_dumptree) | |
3298 | sgftreeAddComment(sgf_dumptree, "Defending ko threat.\n"); | |
3299 | } | |
3300 | } | |
3301 | popgo(); | |
3302 | } | |
3303 | } | |
3304 | set_eyevalue(result, a, 1, 1, d); | |
3305 | if (sgf_dumptree) { | |
3306 | if (a == 0 && d == 1) | |
3307 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0111.\n"); | |
3308 | else if (a == 0 && d == 2) | |
3309 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0112.\n"); | |
3310 | else if (a == 1 && d == 1) | |
3311 | sgftreeAddComment(sgf_dumptree, "Eyevalue 1111.\n"); | |
3312 | else | |
3313 | sgftreeAddComment(sgf_dumptree, "Eyevalue 1112.\n"); | |
3314 | } | |
3315 | } | |
3316 | else if (defense_code != 0) { | |
3317 | /* Critical with extra eye. | |
3318 | * Possible results: 0011, 0012 | |
3319 | */ | |
3320 | int d = 1; | |
3321 | if (sgf_dumptree) | |
3322 | sgftreeAddComment(sgf_dumptree, "Critical with extra eye.\n"); | |
3323 | for (k = 0; k < num_attacks; k++) | |
3324 | vital_attacks[(*num_vital_attacks)++] = attack_points[k]; | |
3325 | for (k = 0; k < num_defenses; k++) { | |
3326 | int move = defense_points[k]; | |
3327 | if (eyegraph_trymove(move, WHITE, "evaluate_eyespace-E", NO_MOVE)) { | |
3328 | evaluate_eyespace(&result2, num_vertices, vertices, | |
3329 | &num_vital_attacks2, vital_attacks2, | |
3330 | &num_vital_defenses2, vital_defenses2, | |
3331 | tactical_life_results); | |
3332 | /* If result2 is 1122 for some move we have 0012 as final | |
3333 | * result, otherwise 0011. | |
3334 | */ | |
3335 | if (min_eye_threat(&result2) == 1 | |
3336 | && min_eyes(&result2) == 1 | |
3337 | && max_eyes(&result2) == 2) { | |
3338 | if (d == 1) | |
3339 | *num_vital_defenses = 0; | |
3340 | d = 2; | |
3341 | vital_defenses[(*num_vital_defenses)++] = move; | |
3342 | } | |
3343 | else if (d == 1) | |
3344 | vital_defenses[(*num_vital_defenses)++] = move; | |
3345 | popgo(); | |
3346 | } | |
3347 | } | |
3348 | set_eyevalue(result, 0, 0, 1, d); | |
3349 | if (sgf_dumptree) { | |
3350 | if (d == 1) | |
3351 | sgftreeAddComment(sgf_dumptree, "Eyevalue: 0011.\n"); | |
3352 | else | |
3353 | sgftreeAddComment(sgf_dumptree, "Eyevalue: 0012.\n"); | |
3354 | } | |
3355 | } | |
3356 | else { | |
3357 | /* Dead with extra eye. | |
3358 | * Possible results: 0000, 0001, 0002 | |
3359 | * | |
3360 | * Determine whether there are ko threats and how serious. | |
3361 | */ | |
3362 | int d = 0; | |
3363 | if (sgf_dumptree) | |
3364 | sgftreeAddComment(sgf_dumptree, "Dead with extra eye.\n"); | |
3365 | num_moves = eyegraph_order_moves(num_vertices, vertices, WHITE, moves); | |
3366 | for (k = 0; k < num_moves; k++) { | |
3367 | int acode, dcode; | |
3368 | int move = moves[k]; | |
3369 | if (eyegraph_trymove(move, WHITE, "evaluate_eyespace-F", NO_MOVE)) { | |
3370 | tactical_life(1, num_vertices, vertices, &acode, NULL, NULL, | |
3371 | &dcode, NULL, NULL, tactical_life_results); | |
3372 | if (dcode != 0) { | |
3373 | tactical_life(0, num_vertices, vertices, &acode, NULL, NULL, | |
3374 | &dcode, NULL, NULL, tactical_life_results); | |
3375 | if (dcode != 0) { | |
3376 | if (d == 1) | |
3377 | *num_vital_defenses = 0; | |
3378 | d = 2; | |
3379 | vital_defenses[(*num_vital_defenses)++] = move; | |
3380 | if (sgf_dumptree) | |
3381 | sgftreeAddComment(sgf_dumptree, | |
3382 | "Ko threat to make two eyes.\n"); | |
3383 | } | |
3384 | else { | |
3385 | if (d != 2) { | |
3386 | vital_defenses[(*num_vital_defenses)++] = move; | |
3387 | d = 1; | |
3388 | } | |
3389 | if (sgf_dumptree) | |
3390 | sgftreeAddComment(sgf_dumptree, | |
3391 | "Ko threat to make one eye.\n"); | |
3392 | } | |
3393 | } | |
3394 | popgo(); | |
3395 | } | |
3396 | } | |
3397 | set_eyevalue(result, 0, 0, 0, d); | |
3398 | if (sgf_dumptree) { | |
3399 | if (d == 0) | |
3400 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0000.\n"); | |
3401 | else if (d == 1) | |
3402 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0001.\n"); | |
3403 | else | |
3404 | sgftreeAddComment(sgf_dumptree, "Eyevalue 0002.\n"); | |
3405 | } | |
3406 | } | |
3407 | } | |
3408 | } | |
3409 | ||
3410 | /* Add small invincible black groups in contact with the marginal | |
3411 | * vertices, without destroying the connectivity of the white stones. | |
3412 | * | |
3413 | */ | |
3414 | static int | |
3415 | add_margins(int num_margins, int *margins, int mx[BOARDMAX]) | |
3416 | { | |
3417 | int k; | |
3418 | int i, j; | |
3419 | int old_mx[BOARDMAX]; | |
3420 | int pos; | |
3421 | ||
3422 | if (num_margins == 0) | |
3423 | return 1; | |
3424 | ||
3425 | memcpy(old_mx, mx, sizeof(old_mx)); | |
3426 | ||
3427 | pos = margins[num_margins - 1]; | |
3428 | ||
3429 | for (k = 0; k < 4; k++) { | |
3430 | int up = delta[k]; | |
3431 | int right = delta[(k + 1) % 4]; | |
3432 | ||
3433 | if (!ON_BOARD(pos + up)) | |
3434 | continue; | |
3435 | ||
3436 | if (mx[pos + up] == WHITE | |
3437 | && (!ON_BOARD(pos + up + right) || mx[pos + up + right] == WHITE) | |
3438 | && (!ON_BOARD(pos + up - right) || mx[pos + up - right] == WHITE)) { | |
3439 | for (i = -3; i <= 0; i++) { | |
3440 | for (j = 2; j < 6; j++) { | |
3441 | if (white_area(mx, pos + j * up + i * right, up, right, pos, j)) { | |
3442 | int s = 1; | |
3443 | while (mx[pos + s * up] == WHITE) { | |
3444 | mx[pos + s * up] = BLACK; | |
3445 | s++; | |
3446 | } | |
3447 | if (add_margins(num_margins - 1, margins, mx)) | |
3448 | return 1; | |
3449 | else | |
3450 | memcpy(mx, old_mx, sizeof(old_mx)); | |
3451 | } | |
3452 | } | |
3453 | } | |
3454 | } | |
3455 | } | |
3456 | ||
3457 | return 0; | |
3458 | } | |
3459 | ||
3460 | /* Analyze an eye graph to determine the eye value and vital moves. | |
3461 | * | |
3462 | * The eye graph is given by a string which is encoded with "%" for | |
3463 | * newlines and "O" for spaces. E.g., the eye graph | |
3464 | * | |
3465 | * ! | |
3466 | * .X | |
3467 | * !... | |
3468 | * | |
3469 | * is encoded as "OO!%O.X%!...". (The encoding is needed for the GTP | |
3470 | * interface to this function.) | |
3471 | * | |
3472 | * The result is an eye value and a (nonencoded) pattern showing the | |
3473 | * vital moves, using the same notation as eyes.db. In the example above | |
3474 | * we would get the eye value 0112 and the graph (showing ko threat moves) | |
3475 | * | |
3476 | * @ | |
3477 | * .X | |
3478 | * !.*. | |
3479 | * | |
3480 | * If the eye graph cannot be realized, 0 is returned, 1 otherwise. | |
3481 | */ | |
3482 | int | |
3483 | analyze_eyegraph(const char *coded_eyegraph, struct eyevalue *value, | |
3484 | char *analyzed_eyegraph) | |
3485 | { | |
3486 | int k; | |
3487 | int i, j; | |
3488 | int mini, minj; | |
3489 | int mx[BOARDMAX]; | |
3490 | char mg[BOARDMAX]; | |
3491 | int pos; | |
3492 | ||
3493 | int num_vital_attacks; | |
3494 | int vital_attacks[BOARDMAX]; /* Way larger than necessary. */ | |
3495 | int num_vital_defenses; | |
3496 | int vital_defenses[BOARDMAX]; /* Way larger than necessary. */ | |
3497 | ||
3498 | int maxwidth; | |
3499 | int current_width; | |
3500 | int num_rows; | |
3501 | int horizontal_edge; | |
3502 | int vertical_edge; | |
3503 | ||
3504 | int num_margins; | |
3505 | int margins[BOARDMAX]; /* Way larger than necessary. */ | |
3506 | ||
3507 | int num_vertices; | |
3508 | int vertices[BOARDMAX]; /* Way larger than necessary. */ | |
3509 | ||
3510 | int table_size; | |
3511 | unsigned char *tactical_life_results; | |
3512 | ||
3513 | if (0) | |
3514 | gprintf("Analyze eyegraph %s\n", coded_eyegraph); | |
3515 | ||
3516 | /* Mark the eyespace in the mx array. We construct the position in | |
3517 | * the mx array and copy it to the actual board later. | |
3518 | */ | |
3519 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
3520 | if (ON_BOARD(pos)) | |
3521 | mx[pos] = WHITE; | |
3522 | ||
3523 | /* Find out the size of the eye graph pattern so that we can center | |
3524 | * it properly. | |
3525 | */ | |
3526 | maxwidth = 0; | |
3527 | current_width = 0; | |
3528 | num_rows = 1; | |
3529 | horizontal_edge = -1; | |
3530 | vertical_edge = -1; | |
3531 | for (k = 0; k < (int) strlen(coded_eyegraph); k++) { | |
3532 | if (coded_eyegraph[k] == '\n') | |
3533 | continue; | |
3534 | if (coded_eyegraph[k] == '%') { | |
3535 | num_rows++; | |
3536 | if (current_width > maxwidth) | |
3537 | maxwidth = current_width; | |
3538 | current_width = 0; | |
3539 | } | |
3540 | else { | |
3541 | if (coded_eyegraph[k] == '-') | |
3542 | horizontal_edge = num_rows - 1; | |
3543 | else if (coded_eyegraph[k] == '|') | |
3544 | vertical_edge = current_width; | |
3545 | current_width++; | |
3546 | } | |
3547 | } | |
3548 | if (current_width > maxwidth) | |
3549 | maxwidth = current_width; | |
3550 | ||
3551 | /* Cut out the eyespace from the solid white string. */ | |
3552 | num_margins = 0; | |
3553 | num_vertices = 0; | |
3554 | ||
3555 | if (horizontal_edge == 0) | |
3556 | mini = -1; | |
3557 | else if (horizontal_edge > 0) | |
3558 | mini = board_size - num_rows + 1; | |
3559 | else | |
3560 | mini = (board_size - num_rows) / 2; | |
3561 | ||
3562 | if (vertical_edge == 0) | |
3563 | minj = -1; | |
3564 | else if (vertical_edge > 0) | |
3565 | minj = board_size - maxwidth + 1; | |
3566 | else | |
3567 | minj = (board_size - maxwidth) / 2; | |
3568 | ||
3569 | i = mini; | |
3570 | j = minj; | |
3571 | for (k = 0; k < (int) strlen(coded_eyegraph); k++) { | |
3572 | char c = coded_eyegraph[k]; | |
3573 | if (c == '\n') | |
3574 | continue; | |
3575 | if (c == '%') { | |
3576 | i++; | |
3577 | j = minj - 1; | |
3578 | } | |
3579 | else if (c == 'X' || c == '$') | |
3580 | mx[POS(i, j)] = BLACK; | |
3581 | else if (c == '.' || c == '*' || c == '<' || c == '>' | |
3582 | || c == '!' || c == '@' || c == '(' || c == ')') | |
3583 | mx[POS(i, j)] = EMPTY; | |
3584 | if (c == '!' || c == '@' || c == '(' || c == ')' || c == '$') | |
3585 | margins[num_margins++] = POS(i, j); | |
3586 | if (c != '|' && c != '-' && c != '+' && c != '%' | |
3587 | && ON_BOARD(POS(i, j)) && mx[POS(i, j)] != WHITE) | |
3588 | vertices[num_vertices++] = POS(i, j); | |
3589 | j++; | |
3590 | } | |
3591 | ||
3592 | /* Add an invincible black group in the lower left plus two outer | |
3593 | * liberties for the white string. However, if the eyespace is | |
3594 | * placed in or near the lower left corner, we put this group in the | |
3595 | * upper right instead. | |
3596 | */ | |
3597 | pos = POS(board_size - 2, 1); | |
3598 | if ((vertical_edge == 0 && horizontal_edge != 0) | |
3599 | || (horizontal_edge > 0 && vertical_edge <= 0)) | |
3600 | pos = POS(1, board_size - 2); | |
3601 | mx[pos] = EMPTY; | |
3602 | mx[NORTH(pos)] = BLACK; | |
3603 | mx[NW(pos)] = BLACK; | |
3604 | mx[NE(pos)] = EMPTY; | |
3605 | mx[WEST(pos)] = BLACK; | |
3606 | mx[EAST(pos)] = BLACK; | |
3607 | mx[SW(pos)] = EMPTY; | |
3608 | mx[SOUTH(pos)] = BLACK; | |
3609 | mx[SE(pos)] = BLACK; | |
3610 | if (ON_BOARD(NN(pos))) | |
3611 | mx[NN(pos)] = EMPTY; | |
3612 | else | |
3613 | mx[SS(pos)] = EMPTY; | |
3614 | ||
3615 | /* Add the two outer liberties in the lower left or upper right to | |
3616 | * the list of vertices. | |
3617 | */ | |
3618 | if (ON_BOARD(NN(pos))) { | |
3619 | vertices[num_vertices++] = NE(pos); | |
3620 | vertices[num_vertices++] = NN(pos); | |
3621 | } | |
3622 | else { | |
3623 | vertices[num_vertices++] = SW(pos); | |
3624 | vertices[num_vertices++] = SS(pos); | |
3625 | } | |
3626 | ||
3627 | /* Add an extra eye in the upper left corner. */ | |
3628 | mx[POS(0, 0)] = EMPTY; | |
3629 | vertices[num_vertices++] = POS(0, 0); | |
3630 | ||
3631 | if (!add_margins(num_margins, margins, mx)) | |
3632 | return 0; | |
3633 | ||
3634 | /* Copy the mx array over to the board. */ | |
3635 | clear_board(); | |
3636 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
3637 | if (ON_BOARD(pos)) { | |
3638 | if (mx[pos] == WHITE) | |
3639 | add_stone(pos, WHITE); | |
3640 | else if (mx[pos] == BLACK) | |
3641 | add_stone(pos, BLACK); | |
3642 | } | |
3643 | ||
3644 | if (verbose) | |
3645 | showboard(0); | |
3646 | ||
3647 | /* If there are any isolated O stones, those should also be added to | |
3648 | * the playable vertices. | |
3649 | */ | |
3650 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) | |
3651 | if (board[pos] == WHITE && !same_string(pos, POS(1, 0))) { | |
3652 | vertices[num_vertices] = vertices[num_vertices - 1]; | |
3653 | vertices[num_vertices - 1] = vertices[num_vertices - 2]; | |
3654 | vertices[num_vertices - 2] = vertices[num_vertices - 3]; | |
3655 | vertices[num_vertices - 3] = pos; | |
3656 | num_vertices++; | |
3657 | } | |
3658 | ||
3659 | if (verbose) { | |
3660 | int k; | |
3661 | gprintf("\nPlayable vertices:\n"); | |
3662 | for (k = 0; k < num_vertices; k++) | |
3663 | gprintf("%1m ", vertices[k]); | |
3664 | gprintf("\n\n"); | |
3665 | } | |
3666 | ||
3667 | /* Disable this test if you need to evaluate larger eyespaces, have | |
3668 | * no shortage of memory, and know what you're doing. | |
3669 | */ | |
3670 | if (num_vertices > 17) { | |
3671 | gprintf("analyze_eyegraph: too large eyespace, %d vertices\n", | |
3672 | num_vertices); | |
3673 | gg_assert(num_vertices <= 17); | |
3674 | } | |
3675 | ||
3676 | /* The cache must have 2*3^num_vertices entries. */ | |
3677 | table_size = 2; | |
3678 | for (k = 0; k < num_vertices; k++) | |
3679 | table_size *= 3; | |
3680 | ||
3681 | /* Allocate memory for the cache. */ | |
3682 | tactical_life_results = malloc(table_size); | |
3683 | if (!tactical_life_results) { | |
3684 | gprintf("analyze_eyegraph: failed to allocate %d bytes\n", table_size); | |
3685 | gg_assert(tactical_life_results != NULL); | |
3686 | } | |
3687 | memset(tactical_life_results, 0, table_size); | |
3688 | ||
3689 | if (sgf_dumptree) | |
3690 | sgffile_printboard(sgf_dumptree); | |
3691 | ||
3692 | /* Evaluate the eyespace on the board. */ | |
3693 | evaluate_eyespace(value, num_vertices, vertices, | |
3694 | &num_vital_attacks, vital_attacks, | |
3695 | &num_vital_defenses, vital_defenses, | |
3696 | tactical_life_results); | |
3697 | ||
3698 | /* Return the cache memory. */ | |
3699 | free(tactical_life_results); | |
3700 | ||
3701 | if (verbose) { | |
3702 | gprintf("Eyevalue: %s\n", eyevalue_to_string(value)); | |
3703 | for (k = 0; k < num_vital_attacks; k++) | |
3704 | gprintf(" vital attack point %1m\n", vital_attacks[k]); | |
3705 | for (k = 0; k < num_vital_defenses; k++) | |
3706 | gprintf(" vital defense point %1m\n", vital_defenses[k]); | |
3707 | } | |
3708 | ||
3709 | /* Encode the attack and defense points with symbols in the mg[] array. */ | |
3710 | memset(mg, ' ', sizeof(mg)); | |
3711 | ||
3712 | for (k = 0; k < num_vertices - 2; k++) | |
3713 | mg[vertices[k]] = (board[vertices[k]] == BLACK ? 'X' : '.'); | |
3714 | ||
3715 | for (k = 0; k < num_margins; k++) | |
3716 | mg[margins[k]] = (mg[margins[k]] == 'X' ? '$' : '!'); | |
3717 | ||
3718 | for (k = 0; k < num_vital_attacks; k++) | |
3719 | mg[vital_attacks[k]] = (mg[vital_attacks[k]] == '!' ? '(' : '<'); | |
3720 | ||
3721 | for (k = 0; k < num_vital_defenses; k++) { | |
3722 | int pos = vital_defenses[k]; | |
3723 | if (mg[pos] == '.') | |
3724 | mg[pos] = '>'; | |
3725 | else if (mg[pos] == '!') | |
3726 | mg[pos] = ')'; | |
3727 | else if (mg[pos] == '<') | |
3728 | mg[pos] = '*'; | |
3729 | else if (mg[pos] == '(') | |
3730 | mg[pos] = '@'; | |
3731 | } | |
3732 | ||
3733 | /* Return the central part of the mg[] array (corresponding to the | |
3734 | * input eye graph). | |
3735 | */ | |
3736 | k = 0; | |
3737 | for (i = mini; i < mini + num_rows; i++) { | |
3738 | for (j = minj; j < minj + maxwidth; j++) { | |
3739 | if ((i < 0 || i >= board_size) && (j < 0 || j >= board_size)) | |
3740 | analyzed_eyegraph[k++] = '+'; | |
3741 | else if (i < 0 || i >= board_size) | |
3742 | analyzed_eyegraph[k++] = '-'; | |
3743 | else if (j < 0 || j >= board_size) | |
3744 | analyzed_eyegraph[k++] = '|'; | |
3745 | else | |
3746 | analyzed_eyegraph[k++] = mg[POS(i, j)]; | |
3747 | } | |
3748 | analyzed_eyegraph[k++] = '\n'; | |
3749 | } | |
3750 | analyzed_eyegraph[k - 1] = 0; | |
3751 | ||
3752 | return 1; | |
3753 | } | |
3754 | ||
3755 | ||
3756 | /* | |
3757 | * Local Variables: | |
3758 | * tab-width: 8 | |
3759 | * c-basic-offset: 2 | |
3760 | * End: | |
3761 | */ |