/* Find moves turning supposed territory into seki. This is not * detected above since it either involves an ALIVE dragon adjacent to * a CRITICAL dragon, or an ALIVE dragon whose eyespace can be invaded * and turned into a seki. * * Currently we only search for tactically critical strings with * dragon status dead, which are neighbors of only one opponent * dragon, which is alive. Through semeai analysis we then determine * whether such a string can in fact live in seki. Relevant testcases * include gunnar:42 and gifu03:2. */ static void find_moves_to_make_seki() { int str; int defend_move; int resulta, resultb; for (str = BOARDMIN; str < BOARDMAX; str++) { if (IS_STONE(board[str]) && is_worm_origin(str, str) && attack_and_defend(str, NULL, NULL, NULL, &defend_move) && dragon[str].status == DEAD && DRAGON2(str).hostile_neighbors == 1) { int k; int color = board[str]; int opponent = NO_MOVE; int certain; struct eyevalue reduced_genus; for (k = 0; k < DRAGON2(str).neighbors; k++) { opponent = dragon2[DRAGON2(str).adjacent[k]].origin; if (board[opponent] != color) break; } ASSERT1(opponent != NO_MOVE, opponent); if (dragon[opponent].status != ALIVE) continue; /* FIXME: These heuristics are used for optimization. We don't * want to call expensive semeai code if the opponent * dragon has more than one eye elsewhere. However, the * heuristics might still need improvement. */ compute_dragon_genus(opponent, &reduced_genus, str); if (DRAGON2(opponent).moyo_size > 10 || min_eyes(&reduced_genus) > 1) continue; owl_analyze_semeai_after_move(defend_move, color, opponent, str, &resulta, &resultb, NULL, 1, &certain, 0); /* Do not trust uncertain results. In fact it should only take a * few nodes to determine the semeai result, if it is a proper * potential seki position. */ if (resultb != WIN && certain) { int d = dragon[str].id; DEBUG(DEBUG_SEMEAI, "Move to make seki at %1m (%1m vs %1m)\n", defend_move, str, opponent); dragon2[d].semeais++; update_status(str, CRITICAL, CRITICAL); dragon2[d].semeai_defense_point = defend_move; dragon2[d].semeai_defense_certain = certain; dragon2[d].semeai_defense_target = opponent; /* We need to determine a proper attack move (the one that * prevents seki). Currently we try the defense move first, * and if it doesn't work -- all liberties of the string. */ owl_analyze_semeai_after_move(defend_move, OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) dragon2[d].semeai_attack_point = defend_move; else { int k; int libs[MAXLIBS]; int liberties = findlib(str, MAXLIBS, libs); for (k = 0; k < liberties; k++) { owl_analyze_semeai_after_move(libs[k], OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) { dragon2[d].semeai_attack_point = libs[k]; break; } } /* FIXME: What should we do if none of the tried attacks worked? */ if (k == liberties) dragon2[d].semeai_attack_point = defend_move; } DEBUG(DEBUG_SEMEAI, "Move to prevent seki at %1m (%1m vs %1m)\n", dragon2[d].semeai_attack_point, opponent, str); dragon2[d].semeai_attack_certain = certain; dragon2[d].semeai_attack_target = opponent; } } } }
/* Find moves turning supposed territory into seki. This is not * detected above since it either involves an ALIVE dragon adjacent to * a CRITICAL dragon, or an ALIVE dragon whose eyespace can be invaded * and turned into a seki. * * Currently we only search for tactically critical strings with * dragon status dead, which are neighbors of only one opponent * dragon, which is alive. Through semeai analysis we then determine * whether such a string can in fact live in seki. Relevant testcases * include gunnar:42 and gifu03:2. */ static void find_moves_to_make_seki() { int str; int defend_move; int resulta, resultb; for (str = BOARDMIN; str < BOARDMAX; str++) { if (IS_STONE(board[str]) && is_worm_origin(str, str) && attack_and_defend(str, NULL, NULL, NULL, &defend_move) && dragon[str].status == DEAD && DRAGON2(str).hostile_neighbors == 1) { int k; int color = board[str]; int opponent = NO_MOVE; int certain; struct eyevalue reduced_genus; for (k = 0; k < DRAGON2(str).neighbors; k++) { opponent = dragon2[DRAGON2(str).adjacent[k]].origin; if (board[opponent] != color) break; } ASSERT1(opponent != NO_MOVE, opponent); if (dragon[opponent].status != ALIVE) continue; /* FIXME: These heuristics are used for optimization. We don't * want to call expensive semeai code if the opponent * dragon has more than one eye elsewhere. However, the * heuristics might still need improvement. */ compute_dragon_genus(opponent, &reduced_genus, str); if (min_eyes(&reduced_genus) > 1 || DRAGON2(opponent).moyo_size > 10 || DRAGON2(opponent).moyo_territorial_value > 2.999 || DRAGON2(opponent).escape_route > 0 || DRAGON2(str).escape_route > 0) continue; owl_analyze_semeai_after_move(defend_move, color, opponent, str, &resulta, &resultb, NULL, 1, &certain, 0); if (resultb == WIN) { owl_analyze_semeai(str, opponent, &resultb, &resulta, &defend_move, 1, &certain); resulta = REVERSE_RESULT(resulta); resultb = REVERSE_RESULT(resultb); } /* Do not trust uncertain results. In fact it should only take a * few nodes to determine the semeai result, if it is a proper * potential seki position. */ if (resultb != WIN && certain) { int d = dragon[str].id; DEBUG(DEBUG_SEMEAI, "Move to make seki at %1m (%1m vs %1m)\n", defend_move, str, opponent); dragon2[d].semeais++; update_status(str, CRITICAL, CRITICAL); dragon2[d].semeai_defense_code = REVERSE_RESULT(resultb); dragon2[d].semeai_defense_point = defend_move; dragon2[d].semeai_defense_certain = certain; gg_assert(board[opponent] == OTHER_COLOR(board[dragon2[d].origin])); dragon2[d].semeai_defense_target = opponent; /* We need to determine a proper attack move (the one that * prevents seki). Currently we try the defense move first, * and if it doesn't work -- all liberties of the string. */ owl_analyze_semeai_after_move(defend_move, OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) { dragon2[d].semeai_attack_code = REVERSE_RESULT(resulta); dragon2[d].semeai_attack_point = defend_move; } else { int k; int libs[MAXLIBS]; int liberties = findlib(str, MAXLIBS, libs); for (k = 0; k < liberties; k++) { owl_analyze_semeai_after_move(libs[k], OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) { dragon2[d].semeai_attack_code = REVERSE_RESULT(resulta); dragon2[d].semeai_attack_point = libs[k]; break; } } if (k == liberties) { DEBUG(DEBUG_SEMEAI, "No move to attack in semeai (%1m vs %1m), seki assumed.\n", str, opponent); dragon2[d].semeai_attack_code = 0; dragon2[d].semeai_attack_point = NO_MOVE; update_status(str, ALIVE, ALIVE_IN_SEKI); } } DEBUG(DEBUG_SEMEAI, "Move to prevent seki at %1m (%1m vs %1m)\n", dragon2[d].semeai_attack_point, opponent, str); dragon2[d].semeai_attack_certain = certain; dragon2[d].semeai_attack_target = opponent; } } } /* Now look for dead strings inside a single eyespace of a living dragon. * * FIXME: Clearly this loop should share most of its code with the * one above. It would also be good to reimplement so that * moves invading a previously empty single eyespace to make * seki can be found. */ for (str = BOARDMIN; str < BOARDMAX; str++) { if (IS_STONE(board[str]) && is_worm_origin(str, str) && !find_defense(str, NULL) && dragon[str].status == DEAD && DRAGON2(str).hostile_neighbors == 1) { int k; int color = board[str]; int opponent = NO_MOVE; int certain; struct eyevalue reduced_genus; for (k = 0; k < DRAGON2(str).neighbors; k++) { opponent = dragon2[DRAGON2(str).adjacent[k]].origin; if (board[opponent] != color) break; } ASSERT1(opponent != NO_MOVE, opponent); if (dragon[opponent].status != ALIVE) continue; /* FIXME: These heuristics are used for optimization. We don't * want to call expensive semeai code if the opponent * dragon has more than one eye elsewhere. However, the * heuristics might still need improvement. */ compute_dragon_genus(opponent, &reduced_genus, str); if (DRAGON2(opponent).moyo_size > 10 || min_eyes(&reduced_genus) > 1) continue; owl_analyze_semeai(str, opponent, &resulta, &resultb, &defend_move, 1, &certain); /* Do not trust uncertain results. In fact it should only take a * few nodes to determine the semeai result, if it is a proper * potential seki position. */ if (resulta != 0 && certain) { int d = dragon[str].id; DEBUG(DEBUG_SEMEAI, "Move to make seki at %1m (%1m vs %1m)\n", defend_move, str, opponent); dragon2[d].semeais++; update_status(str, CRITICAL, CRITICAL); dragon2[d].semeai_defense_code = resulta; dragon2[d].semeai_defense_point = defend_move; dragon2[d].semeai_defense_certain = certain; gg_assert(board[opponent] == OTHER_COLOR(board[dragon2[d].origin])); dragon2[d].semeai_defense_target = opponent; /* We need to determine a proper attack move (the one that * prevents seki). Currently we try the defense move first, * and if it doesn't work -- all liberties of the string. */ owl_analyze_semeai_after_move(defend_move, OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) { dragon2[d].semeai_attack_code = REVERSE_RESULT(resulta); dragon2[d].semeai_attack_point = defend_move; } else { int k; int libs[MAXLIBS]; int liberties = findlib(str, MAXLIBS, libs); for (k = 0; k < liberties; k++) { owl_analyze_semeai_after_move(libs[k], OTHER_COLOR(color), str, opponent, &resulta, NULL, NULL, 1, NULL, 0); if (resulta != WIN) { dragon2[d].semeai_attack_code = REVERSE_RESULT(resulta); dragon2[d].semeai_attack_point = libs[k]; break; } } if (k == liberties) { DEBUG(DEBUG_SEMEAI, "No move to attack in semeai (%1m vs %1m), seki assumed.\n", str, opponent); dragon2[d].semeai_attack_code = 0; dragon2[d].semeai_attack_point = NO_MOVE; update_status(str, ALIVE, ALIVE_IN_SEKI); } } DEBUG(DEBUG_SEMEAI, "Move to prevent seki at %1m (%1m vs %1m)\n", dragon2[d].semeai_attack_point, opponent, str); dragon2[d].semeai_attack_certain = certain; dragon2[d].semeai_attack_target = opponent; } } } }