void
sgf_trace_semeai(const char *func, int str1, int str2, int move,
int result1, int result2, const char *message)
{
char buf[100];
sprintf(buf, "%s %c%d %c%d: ", func,
J(str1) + 'A' + (J(str1) >= 8), board_size - I(str1),
J(str2) + 'A' + (J(str2) >= 8), board_size - I(str2));
if (ON_BOARD(move))
sprintf(buf + strlen(buf), "%s %s %c%d",
result_to_string(result1), result_to_string(result2),
J(move) + 'A' + (J(move) >= 8), board_size - I(move));
else if (is_pass(move))
sprintf(buf + strlen(buf), "%s %s PASS",
result_to_string(result1), result_to_string(result2));
else
sprintf(buf + strlen(buf), "%s %s [%d]",
result_to_string(result1), result_to_string(result2),
move);
if (message)
sprintf(buf + strlen(buf), " (%s)", message);
sgftreeAddComment(sgf_dumptree, buf);
}
void
clear_unconditionally_meaningless_moves()
{
int pos;
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos)) {
meaningless_black_moves[pos] = -1;
meaningless_white_moves[pos] = -1;
}
}
static int
goal_dist(int pos, signed char goal[BOARDMAX])
{
int dist = 10000;
int ii;
for (ii = BOARDMIN; ii < BOARDMAX; ii++)
if (ON_BOARD(ii) && goal[ii])
dist = gg_min(dist, square_dist(ii, pos));
return dist;
}
/* neighbor_of_dragon(pos, origin) returns true if the vertex at (pos) is a
* neighbor of the dragon with origin at (origin).
*/
static int
neighbor_of_dragon(int pos, int origin)
{
int k;
if (pos == NO_MOVE)
return 0;
for (k = 0; k < 4; k++)
if (ON_BOARD(pos + delta[k]) && dragon[pos + delta[k]].origin == origin)
return 1;
return 0;
}
/* Compute hash value to identify the goal area.
*
* FIXME: It would be cleaner to have a separate zobrist array for the
* goal and xor the values in goal as usual.
*/
Hash_data
goal_to_hashvalue(const char *goal)
{
int i, pos;
Hash_data return_value;
for (i = 0; i < NUM_HASHVALUES; i++)
return_value.hashval[i] = 0;
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos) && goal[pos])
for (i = 0; i < NUM_HASHVALUES; i++)
return_value.hashval[i] += (white_hash[pos].hashval[i]
+ black_hash[pos].hashval[i]);
return return_value;
}
/* Returns 1 if the stored board is compatible with the current board,
* 0 otherwise.
*/
static int
verify_stored_board(char p[BOARDMAX])
{
int pos;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
else if (p[pos] == GRAY)
continue;
else if ((p[pos] & 3) != board[pos])
return 0;
else if (!(p[pos] & HIGH_LIBERTY_BIT))
continue;
else if (countlib(pos) <= 4)
return 0;
}
return 1;
}
void
decide_combination(int color)
{
int attack_move;
char defense_moves[BOARDMAX];
SGFTree tree;
int first = 1;
int pos;
/* Prepare pattern matcher and reading code. */
reset_engine();
silent_examine_position(color, EXAMINE_ALL);
if (*outfilename)
sgffile_begindump(&tree);
count_variations = 1;
if (atari_atari(color, &attack_move, defense_moves, verbose)) {
gprintf("Combination attack for %C at %1m, defense at ", color,
attack_move);
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (ON_BOARD(pos) && defense_moves[pos]) {
if (first)
first = 0;
else
gprintf(", ");
gprintf("%1m", pos);
}
}
gprintf("\n");
}
else
gprintf("No Combination attack for %C\n", color);
sgffile_enddump(outfilename);
count_variations = 0;
}
/* Look for a valid read result in the persistent cache.
* Return 1 if found, 0 otherwise.
*/
int
search_persistent_reading_cache(int routine, int str, int *result, int *move)
{
int k;
struct reading_cache *entry;
k = find_persistent_reading_cache_entry(routine, str);
if (k == -1)
return 0;
/* Match found. Increase score and fill in the answer. */
entry = &(persistent_reading_cache[k]);
entry->score += entry->nodes;
if (result)
*result = entry->result;
if (move)
*move = entry->move;
ASSERT1(entry->result == 0
|| entry->move == NO_MOVE
|| ON_BOARD(entry->move),
entry->move);
if ((debug & DEBUG_READING_PERFORMANCE)
&& entry->nodes >= MIN_READING_NODES_TO_REPORT) {
if (entry->result != 0)
gprintf("%o%s %1m = %d %1m, cached (%d nodes) ",
routine == ATTACK ? "attack" : "defend",
str, entry->result, entry->move, entry->nodes);
else
gprintf("%o%s %1m = %d, cached (%d nodes) ",
routine == ATTACK ? "attack" : "defend",
str, entry->result, entry->nodes);
dump_stack();
}
return 1;
}
void
decide_position(int color)
{
int pos;
int move = NO_MOVE;
int acode = 0, dcode = 0;
int kworm;
static const char *snames[] = {"dead", "alive", "critical", "unknown"};
SGFTree tree;
/* Prepare pattern matcher and reading code. */
reset_engine();
silent_examine_position(color, EXAMINE_DRAGONS_WITHOUT_OWL);
/* We want to see the reading performed, not just a result picked
* from the cache. Thus we clear the cache here. */
reading_cache_clear();
if (*outfilename)
sgffile_begindump(&tree);
count_variations = 1;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos)
|| dragon[pos].origin != pos
|| board[pos] == EMPTY
|| DRAGON2(pos).escape_route >= 6)
continue;
gprintf("\nanalyzing %1m\n", pos);
gprintf("status=%s, escape=%d\n",
snames[dragon[pos].crude_status], DRAGON2(pos).escape_route);
acode = owl_attack(pos, &move, NULL, &kworm);
if (acode) {
if (acode == WIN) {
if (move == NO_MOVE)
gprintf("%1m is dead as it stands\n", pos);
else
gprintf("%1m can be attacked at %1m (%d variations)\n",
pos, move, count_variations);
}
else if (acode == KO_A)
gprintf("%1m can be attacked with ko (good) at %1m (%d variations)\n",
pos, move, count_variations);
else if (acode == KO_B)
gprintf("%1m can be attacked with ko (bad) at %1m (%d variations)\n",
pos, move, count_variations);
else if (acode == GAIN)
gprintf("%1m can be attacked with gain (captures %1m) at %1m (%d variations)",
pos, kworm, move, count_variations);
count_variations = 1;
dcode = owl_defend(pos, &move, NULL, &kworm);
if (dcode) {
if (dcode == WIN) {
if (move == NO_MOVE)
gprintf("%1m is alive as it stands\n", pos);
else
gprintf("%1m can be defended at %1m (%d variations)\n",
pos, move, count_variations);
}
else if (dcode == KO_A)
gprintf("%1m can be defended with ko (good) at %1m (%d variations)\n",
pos, move, count_variations);
else if (dcode == KO_B)
gprintf("%1m can be defended with ko (bad) at %1m (%d variations)\n",
pos, move, count_variations);
else if (dcode == LOSS)
gprintf("%1m can be defended with loss (loses %1m) at %1m (%d variations)",
pos, kworm, move, count_variations);
}
else
gprintf("%1m cannot be defended (%d variations)\n",
pos, count_variations);
}
else
gprintf("%1m cannot be attacked (%d variations)\n",
pos, count_variations);
if (acode) {
if (dcode)
gprintf("status of %1m revised to CRITICAL\n", pos);
else
gprintf("status of %1m revised to DEAD\n", pos);
}
else
gprintf("status of %1m revised to ALIVE\n", pos);
}
sgffile_enddump(outfilename);
count_variations = 0;
}
/* Generate a move to definitely settle the position after the game
* has been finished. The purpose of this is to robustly determine
* life and death status and to distinguish between life in seki and
* life with territory.
*
* The strategy is basically to turn all own living stones into
* invincible ones and remove from the board all dead opponent stones.
* Stones which cannot be removed, nor turned invincible, are alive in
* seki.
*
* If do_capture_dead_stones is 0, opponent stones are not necessarily
* removed from the board. This happens if they become unconditionally
* dead anyway.
*
* Moves are generated in the following order of priority:
* 0. Play edge liberties in certain positions. This is not really
* necessary, but often it can simplify the tactical and strategical
* reading substantially, making subsequent moves faster to generate.
* 1. Capture an opponent string in atari and adjacent to own
* invincible string. Moves leading to ko or snapback are excluded.
* 2. Extend an invincible string to a liberty of an opponent string.
* 3. Connect a non-invincible string to an invincible string.
* 4. Extend an invincible string towards an opponent string or an own
* non-invincible string.
* 5. Split a big eyespace of an alive own dragon without invincible
* strings into smaller pieces.
* 6. Play a liberty of a dead opponent dragon.
*
* Steps 2--4 are interleaved to try to optimize the efficiency of the
* moves. In step 5 too, efforts are made to play efficient moves. By
* efficient we here mean moves which are effectively settling the
* position and simplify the tactical and strategical reading for
* subsequent moves.
*
* Steps 1--4 are guaranteed to be completely safe. Step 0 and 5
* should also be risk-free. Step 6 on the other hand definitely
* isn't. Consider for example this position:
*
* .XXXXX.
* XXOOOXX
* XOO.OOX
* XOXXXOX
* XO.XXOX
* -------
*
* In order to remove the O stones, it is necessary to play on one of
* the inner liberties, but one of them lets O live. Thus we have to
* check carefully for blunders at this step.
*
* Update: Step 0 is only safe against blunders if care is taken not
* to get into a shortage of liberties.
* Step 5 also has some risks. Consider this position:
*
* |XXXXX.
* |OOOOXX
* |..O.OX
* |OX*OOX
* +------
*
* Playing at * allows X to make seki.
*
* IMPORTANT RESTRICTION:
* Before calling this function it is mandatory to call genmove() or
* genmove_conservative(). For this function to be meaningful, the
* genmove() call should return pass.
*/
int
aftermath_genmove(int *aftermath_move, int color,
int under_control[BOARDMAX],
int do_capture_dead_stones)
{
int k;
int other = OTHER_COLOR(color);
int distance[BOARDMAX];
int score[BOARDMAX];
float owl_hotspot[BOARDMAX];
float reading_hotspot[BOARDMAX];
int dragons[BOARDMAX];
int something_found;
int closest_opponent = NO_MOVE;
int closest_own = NO_MOVE;
int d;
int move = NO_MOVE;
int pos = NO_MOVE;
int best_score;
int best_scoring_move;
owl_hotspots(owl_hotspot);
reading_hotspots(reading_hotspot);
/* As a preparation we compute a distance map to the invincible strings. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
else if (board[pos] == color && worm[pos].invincible)
distance[pos] = 0;
else if (!do_capture_dead_stones
&& ((board[pos] == other
&& worm[pos].unconditional_status == DEAD)
|| (board[pos] == color
&& worm[pos].unconditional_status == ALIVE)))
distance[pos] = 0;
else
distance[pos] = -1;
}
d = 0;
do {
something_found = 0;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (ON_BOARD(pos) && distance[pos] == -1) {
for (k = 0; k < 4; k++) {
int pos2 = pos + delta[k];
if (!ON_BOARD(pos2))
continue;
if ((d == 0 || board[pos2] == EMPTY)
&& distance[pos2] == d) {
if (d > 0 && board[pos] == other) {
distance[pos] = d + 1;
if (closest_opponent == NO_MOVE)
closest_opponent = pos;
}
else if (d > 0 && board[pos] == color) {
distance[pos] = d + 1;
if (closest_own == NO_MOVE)
closest_own = pos;
}
else if (board[pos] == EMPTY) {
distance[pos] = d + 1;
something_found = 1;
}
break;
}
}
}
}
d++;
} while (something_found);
if (under_control) {
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
else if (distance[pos] == -1)
under_control[pos] = 0;
else
under_control[pos] = 1;
}
}
if (debug & DEBUG_AFTERMATH) {
int m, n;
for (m = 0; m < board_size; m++) {
for (n = 0; n < board_size; n++) {
pos = POS(m, n);
if (distance[pos] > 0)
fprintf(stderr, "%2d", distance[pos]);
else if (distance[pos] == 0) {
if (board[pos] == WHITE)
gprintf(" o");
else if (board[pos] == BLACK)
gprintf(" x");
else
gprintf(" ?");
}
else {
if (board[pos] == WHITE)
gprintf(" O");
else if (board[pos] == BLACK)
gprintf(" X");
else
gprintf(" .");
}
}
gprintf("\n");
}
gprintf("Closest opponent %1m", closest_opponent);
if (closest_opponent != NO_MOVE)
gprintf(", distance %d\n", distance[closest_opponent]);
else
gprintf("\n");
gprintf("Closest own %1m", closest_own);
if (closest_own != NO_MOVE)
gprintf(", distance %d\n", distance[closest_own]);
else
gprintf("\n");
}
/* Case 0. This is a special measure to avoid a certain kind of
* tactical reading inefficiency.
*
* Here we play on edge liberties in the configuration
*
* XO.
* .*.
* ---
*
* to stop X from "leaking" out along the edge. Sometimes this can
* save huge amounts of tactical reading for later moves.
*/
best_scoring_move = NO_MOVE;
best_score = 5;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int libs;
if (board[pos] != EMPTY
|| distance[pos] == 0)
continue;
libs = approxlib(pos, color, 3, NULL);
if (libs < 3)
continue;
if (is_self_atari(pos, other))
continue;
for (k = 0; k < 4; k++) {
int dir = delta[k];
int right = delta[(k+1)%4];
if (!ON_BOARD(pos - dir)
&& board[pos + dir] == color
&& board[pos + dir + right] == other
&& board[pos + dir - right] == other
&& (libs > countlib(pos + dir)
|| (libs > 4
&& libs == countlib(pos + dir)))
&& (DRAGON2(pos + dir).safety == INVINCIBLE
|| DRAGON2(pos + dir).safety == STRONGLY_ALIVE)) {
int this_score = 20 * (owl_hotspot[pos] + reading_hotspot[pos]);
if (this_score > best_score) {
best_score = this_score;
best_scoring_move = pos;
}
}
}
}
if (best_scoring_move != NO_MOVE
&& safe_move(best_scoring_move, color) == WIN) {
*aftermath_move = best_scoring_move;
DEBUG(DEBUG_AFTERMATH, "Closing edge at %1m\n", best_scoring_move);
return 1;
}
/* Case 1. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int lib;
if (board[pos] == other
&& worm[pos].unconditional_status != DEAD
&& countlib(pos) == 1
&& ((ON_BOARD(SOUTH(pos)) && distance[SOUTH(pos)] == 0)
|| (ON_BOARD(WEST(pos)) && distance[WEST(pos)] == 0)
|| (ON_BOARD(NORTH(pos)) && distance[NORTH(pos)] == 0)
|| (ON_BOARD(EAST(pos)) && distance[EAST(pos)] == 0))) {
findlib(pos, 1, &lib);
/* Make sure we don't play into a ko or a (proper) snapback. */
if (countstones(pos) > 1 || !is_self_atari(lib, color)) {
*aftermath_move = lib;
return 1;
}
}
}
/* Cases 2--4. */
if (closest_opponent != NO_MOVE || closest_own != NO_MOVE) {
if (closest_own == NO_MOVE)
move = closest_opponent;
else
move = closest_own;
/* if we're about to play at distance 1, try to optimize the move. */
if (distance[move] == 2) {
char mx[BOARDMAX];
char mark = 0;
memset(mx, 0, sizeof(mx));
best_score = 0;
best_scoring_move = move;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int score = 0;
int move_ok = 0;
if (!ON_BOARD(pos) || distance[pos] != 1)
continue;
mark++;
for (k = 0; k < 4; k++) {
int pos2 = pos + delta[k];
if (!ON_BOARD(pos2))
continue;
if (distance[pos2] < 1)
score--;
else if (board[pos2] == EMPTY)
score++;
else if (mx[pos2] == mark)
score--;
else {
if (board[pos2] == color) {
move_ok = 1;
score += 7;
if (countstones(pos2) > 2)
score++;
if (countstones(pos2) > 4)
score++;
if (countlib(pos2) < 4)
score++;
if (countlib(pos2) < 3)
score++;
}
else {
int deltalib = (approxlib(pos, other, MAXLIBS, NULL)
- countlib(pos2));
move_ok = 1;
score++;
if (deltalib >= 0)
score++;
if (deltalib > 0)
score++;
}
mark_string(pos2, mx, mark);
}
}
if (is_suicide(pos, other))
score -= 3;
if (0)
gprintf("Score %1m = %d\n", pos, score);
if (move_ok && score > best_score) {
best_score = score;
best_scoring_move = pos;
}
}
move = best_scoring_move;
}
while (distance[move] > 1) {
for (k = 0; k < 4; k++) {
int pos2 = move + delta[k];
if (ON_BOARD(pos2)
&& board[pos2] == EMPTY
&& distance[pos2] == distance[move] - 1) {
move = pos2;
break;
}
}
}
*aftermath_move = move;
return 1;
}
/* Case 5.
* If we reach here, either all strings of a dragon are invincible
* or no string is. Next we try to make alive dragons invincible by
* splitting big eyes into smaller ones. Our strategy is to search
* for an empty vertex with as many eye points as possible adjacent
* and with at least one alive but not invincible stone adjacent or
* diagonal.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int eyespace_neighbors = 0;
int own_neighbors = 0;
int own_diagonals = 0;
int opponent_dragons = 0;
int own_worms = 0;
int safety = UNKNOWN;
int bonus = 0;
int mx[BOARDMAX];
score[pos] = 0;
if (board[pos] != EMPTY || distance[pos] != -1)
continue;
memset(mx, 0, sizeof(mx));
for (k = 0; k < 8; k++) {
int pos2 = pos + delta[k];
if (!ON_BOARD(pos2))
continue;
if (board[pos2] == EMPTY) {
if (k < 4)
eyespace_neighbors++;
continue;
}
if (board[pos2] == other) {
int origin = dragon[pos2].origin;
if (k < 4) {
if (dragon[pos2].status == ALIVE) {
safety = DEAD;
break;
}
else if (!mx[origin]) {
eyespace_neighbors++;
opponent_dragons++;
}
}
if (!mx[origin] && dragon[pos2].status == DEAD) {
bonus++;
if (k < 4
&& countlib(pos2) <= 2
&& countstones(pos2) >= 3)
bonus++;
if (k < 4 && countlib(pos2) == 1)
bonus += 3;
}
mx[origin] = 1;
}
else if (board[pos2] == color) {
dragons[pos] = pos2;
if (safety == UNKNOWN && dragon[pos2].status == ALIVE)
safety = ALIVE;
if (DRAGON2(pos2).safety == INVINCIBLE)
safety = INVINCIBLE;
if (k < 4) {
int apos = worm[pos2].origin;
if (!mx[apos]) {
own_worms++;
if (countstones(apos) == 1)
bonus += 2;
if (countlib(apos) < 6
&& approxlib(pos, color, 5, NULL) < countlib(apos))
bonus -= 5;
mx[apos] = 1;
}
if (countlib(apos) <= 2) {
int r;
int important = 0;
int safe_atari = 0;
for (r = 0; r < 4; r++) {
d = delta[r];
if (!ON_BOARD(apos+d))
continue;
if (board[apos+d] == other
&& dragon[apos+d].status == DEAD)
important = 1;
else if (board[apos+d] == EMPTY
&& !is_self_atari(apos+d, other))
safe_atari = 1;
}
if (approxlib(pos, color, 3, NULL) > 2) {
bonus++;
if (important) {
bonus += 2;
if (safe_atari)
bonus += 2;
}
}
}
own_neighbors++;
}
else
own_diagonals++;
}
}
if (safety == DEAD || safety == UNKNOWN
|| eyespace_neighbors == 0
|| (own_neighbors + own_diagonals) == 0)
continue;
if (bonus < 0)
bonus = 0;
score[pos] = 4 * eyespace_neighbors + bonus;
if (safety == INVINCIBLE) {
score[pos] += own_neighbors;
if (own_neighbors < 2)
score[pos] += own_diagonals;
if (own_worms > 1 && eyespace_neighbors >= 1)
score[pos] += 10 + 5 * (own_worms - 2);
}
else if (eyespace_neighbors > 2)
score[pos] += own_diagonals;
/* Splitting bonus. */
if (opponent_dragons > 1)
score[pos] += 10 * (opponent_dragons - 1);
/* Hotspot bonus. */
{
int owl_hotspot_bonus = (int) (20.0 * owl_hotspot[pos]);
int reading_hotspot_bonus = (int) (20.0 * reading_hotspot[pos]);
int hotspot_bonus = owl_hotspot_bonus + reading_hotspot_bonus;
/* Don't allow the hotspot bonus to turn a positive score into
* a non-positive one.
*/
if (score[pos] > 0 && score[pos] + hotspot_bonus <= 0)
hotspot_bonus = 1 - score[pos];
score[pos] += hotspot_bonus;
if (1 && (debug & DEBUG_AFTERMATH))
gprintf("Score %1M = %d (hotspot bonus %d + %d)\n", pos, score[pos],
owl_hotspot_bonus, reading_hotspot_bonus);
}
/* Avoid taking ko. */
if (is_ko(pos, color, NULL))
score[pos] = (score[pos] + 1) / 2;
}
while (1) {
int bb;
best_score = 0;
move = NO_MOVE;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (ON_BOARD(pos) && score[pos] > best_score) {
best_score = score[pos];
move = pos;
}
}
if (move == NO_MOVE)
break;
bb = dragons[move];
if (is_illegal_ko_capture(move, color)
|| !safe_move(move, color)
|| (DRAGON2(bb).safety != INVINCIBLE
&& DRAGON2(bb).safety != STRONGLY_ALIVE
&& owl_does_defend(move, bb, NULL) != WIN)
|| (!confirm_safety(move, color, NULL, NULL))) {
score[move] = 0;
}
else {
/* If we're getting short of liberties, we must be more careful.
* Check that no adjacent string or dragon gets more alive by
* the move.
*/
int libs = approxlib(move, color, 5, NULL);
int move_ok = 1;
if (libs < 5) {
for (k = 0; k < 4; k++) {
if (board[move + delta[k]] == color
&& countlib(move + delta[k]) > libs)
break;
}
if (k < 4) {
if (trymove(move, color, "aftermath-B", move + delta[k])) {
int adjs[MAXCHAIN];
int neighbors;
int r;
neighbors = chainlinks(move, adjs);
for (r = 0; r < neighbors; r++) {
if (worm[adjs[r]].attack_codes[0] != 0
&& (find_defense(adjs[r], NULL)
> worm[adjs[r]].defense_codes[0])) {
DEBUG(DEBUG_AFTERMATH,
"Blunder: %1m becomes tactically safer after %1m\n",
adjs[r], move);
move_ok = 0;
}
}
popgo();
for (r = 0; r < neighbors && move_ok; r++) {
if (dragon[adjs[r]].status == DEAD
&& !owl_does_attack(move, adjs[r], NULL)) {
DEBUG(DEBUG_AFTERMATH,
"Blunder: %1m becomes more alive after %1m\n",
adjs[r], move);
move_ok = 0;
}
}
}
}
}
if (!move_ok)
score[move] = 0;
else {
*aftermath_move = move;
DEBUG(DEBUG_AFTERMATH, "Splitting eyespace at %1m\n", move);
return 1;
}
}
}
/* Case 6.
* Finally we try to play on liberties of remaining DEAD opponent
* dragons, carefully checking against mistakes.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int target;
int cc = NO_MOVE;
int self_atari_ok = 0;
if (board[pos] != EMPTY || distance[pos] != -1)
continue;
target = NO_MOVE;
for (k = 0; k < 4; k++) {
int pos2 = pos + delta[k];
if (!ON_BOARD(pos2))
continue;
if (board[pos2] == other
&& dragon[pos2].status != ALIVE
&& (do_capture_dead_stones
|| worm[pos2].unconditional_status != DEAD)
&& DRAGON2(pos2).safety != INESSENTIAL) {
target = pos2;
break;
}
}
if (target == NO_MOVE)
continue;
/* At this point, (pos) is a move that potentially may capture
* a dead opponent string at (target).
*/
if (!trymove(pos, color, "aftermath-A", target))
continue;
/* It is frequently necessary to sacrifice own stones in order
* to force the opponent's stones to be removed from the board,
* e.g. by adding stones to fill up a nakade shape. However, we
* should only play into a self atari if the sacrificed stones
* are classified as INESSENTIAL. Thus it would be ok for O to
* try a self atari in this position:
*
* |OOOO
* |XXXO
* |..XO
* |OOXO
* +----
*
* but not in this one:
*
* |XXX..
* |OOXX.
* |.OOXX
* |XXOOX
* |.O.OX
* +-----
*/
self_atari_ok = 1;
for (k = 0; k < 4; k++) {
if (board[pos + delta[k]] == color
&& DRAGON2(pos + delta[k]).safety != INESSENTIAL) {
self_atari_ok = 0;
cc = pos + delta[k];
break;
}
}
/* Copy the potential move to (move). */
move = pos;
/* If the move is a self atari, but that isn't okay, try to
* recursively find a backfilling move which later makes the
* potential move possible.
*/
if (!self_atari_ok) {
while (countlib(pos) == 1) {
int lib;
findlib(pos, 1, &lib);
move = lib;
if (!trymove(move, color, "aftermath-B", target))
break;
}
if (countlib(pos) == 1)
move = NO_MOVE;
}
while (stackp > 0)
popgo();
if (move == NO_MOVE)
continue;
/* Make sure that the potential move really isn't a self
* atari. In the case of a move found after backfilling this
* could happen (because the backfilling moves happened to
* capture some stones).
*/
if (!self_atari_ok && is_self_atari(move, color))
continue;
/* Consult the owl code to determine whether the considered move
* really is effective. Blunders should be detected here.
*/
if (owl_does_attack(move, target, NULL) == WIN) {
/* If we have an adjacent own dragon, which is not inessential,
* verify that it remains safe.
*/
if (cc != NO_MOVE && !owl_does_defend(move, cc, NULL))
continue;
/* If we don't allow self atari, also call confirm safety to
* avoid setting up combination attacks.
*/
if (!self_atari_ok && !confirm_safety(move, color, NULL, NULL))
continue;
*aftermath_move = move;
DEBUG(DEBUG_AFTERMATH, "Filling opponent liberty at %1m\n", move);
return 1;
}
}
/* Case 7.
* In very rare cases it turns out we need yet another pass. An
* example is this position:
*
* |.....
* |OOOO.
* |XXXO.
* |.OXO.
* |O.XO.
* +-----
*
* Here the X stones are found tactically dead and therefore the
* corner O stones have been amalgamated with the surrounding
* stones. Since the previous case only allows sacrificing
* INESSENTIAL stones, it fails to take X off the board.
*
* The solution is to look for tactically attackable opponent stones
* that still remain on the board but should be removed.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] == other
&& (worm[pos].unconditional_status == UNKNOWN
|| do_capture_dead_stones)
&& (DRAGON2(pos).safety == DEAD
|| DRAGON2(pos).safety == TACTICALLY_DEAD)
&& worm[pos].attack_codes[0] != 0
&& !is_illegal_ko_capture(worm[pos].attack_points[0], color)) {
*aftermath_move = worm[pos].attack_points[0];
DEBUG(DEBUG_AFTERMATH, "Tactically attack %1m at %1m\n",
pos, *aftermath_move);
return 1;
}
}
/* No move found. */
return -1;
}
static void
play_aftermath(int color)
{
int pos;
struct board_state saved_board;
struct aftermath_data *a = &aftermath;
static int current_board[BOARDMAX];
static int current_color = EMPTY;
int cached_board = 1;
gg_assert(color == BLACK || color == WHITE);
if (current_color != color) {
current_color = color;
cached_board = 0;
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (ON_BOARD(pos) && board[pos] != current_board[pos]) {
current_board[pos] = board[pos];
cached_board = 0;
}
}
/* If this is exactly the same position as the one we analyzed the
* last time, the content of the aftermath struct is up to date.
*/
if (cached_board)
return;
a->white_captured = white_captured;
a->black_captured = black_captured;
a->white_prisoners = 0;
a->black_prisoners = 0;
a->white_territory = 0;
a->black_territory = 0;
a->white_area = 0;
a->black_area = 0;
store_board(&saved_board);
do_play_aftermath(color, a);
restore_board(&saved_board);
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
if (a->black_control[pos]) {
a->black_area++;
if (board[pos] == WHITE) {
a->black_territory++;
a->white_prisoners++;
a->final_status[pos] = DEAD;
}
else if (board[pos] == EMPTY) {
a->black_territory++;
a->final_status[pos] = BLACK_TERRITORY;
}
else
a->final_status[pos] = ALIVE;
}
else if (a->white_control[pos]) {
a->white_area++;
if (board[pos] == BLACK) {
a->white_territory++;
a->black_prisoners++;
a->final_status[pos] = DEAD;
}
else if (board[pos] == EMPTY) {
a->white_territory++;
a->final_status[pos] = WHITE_TERRITORY;
}
else
a->final_status[pos] = ALIVE;
}
else {
if (board[pos] == EMPTY)
a->final_status[pos] = DAME;
else {
a->final_status[pos] = ALIVE_IN_SEKI;
if (board[pos] == WHITE)
a->white_area++;
else
a->black_area++;
}
}
}
if (debug & DEBUG_AFTERMATH) {
gprintf("White captured: %d\n", a->white_captured);
gprintf("Black captured: %d\n", a->black_captured);
gprintf("White prisoners: %d\n", a->white_prisoners);
gprintf("Black prisoners: %d\n", a->black_prisoners);
gprintf("White territory: %d\n", a->white_territory);
gprintf("Black territory: %d\n", a->black_territory);
gprintf("White area: %d\n", a->white_area);
gprintf("Black area: %d\n", a->black_area);
}
}
void
unconditional_life(int unconditional_territory[BOARDMAX], int color)
{
int found_one;
int other = OTHER_COLOR(color);
int libs[MAXLIBS];
int liberties;
int pos;
int k, r;
int moves_played;
int potential_sekis[BOARDMAX];
int none_invincible;
/* Initialize unconditional_territory array. */
memset(unconditional_territory, 0,
sizeof(unconditional_territory[0]) * BOARDMAX);
/* Find isolated two-stone strings which might be involved in the
* kind of seki described in the comments.
*/
memset(potential_sekis, 0, sizeof(potential_sekis));
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int isolated = 1;
int stones[2];
int pos2;
if (board[pos] != color
|| find_origin(pos) != pos
|| countstones(pos) != 2)
continue;
findstones(pos, 2, stones);
for (k = 0; k < 2 && isolated; k++) {
for (r = 0; r < 8 && isolated; r++) {
pos2 = stones[k] + delta[r];
if (!ON_BOARD(pos2)
|| (board[pos2] == color
&& !same_string(pos, pos2)))
isolated = 0;
}
}
if (isolated) {
potential_sekis[stones[0]] = 1;
potential_sekis[stones[1]] = 1;
}
}
moves_played = capture_non_invincible_strings(color, potential_sekis,
&none_invincible);
/* If there are no invincible strings, nothing can be unconditionally
* settled.
*/
if (none_invincible) {
/* Take back all moves. */
while (moves_played > 0) {
popgo();
moves_played--;
}
return;
}
/* The strings still remaining except those marked in
* potential_sekis[] are uncapturable. Now see which opponent
* strings can survive.
*
* 1. Play opponent stones on all liberties of the unconditionally
* alive strings except where illegal.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] != color || potential_sekis[pos] || find_origin(pos) != pos)
continue;
/* Play as many liberties as we can. */
liberties = findlib(pos, MAXLIBS, libs);
for (k = 0; k < liberties; k++) {
if (trymove(libs[k], other, "unconditional_life", pos))
moves_played++;
}
}
/* 2. Recursively extend opponent strings in atari, except where this
* would be suicide.
*/
found_one = 1;
while (found_one) {
/* Nothing found so far in this turn of the loop. */
found_one = 0;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] != other || countlib(pos) > 1)
continue;
/* Try to extend the string at (m, n). */
findlib(pos, 1, libs);
if (trymove(libs[0], other, "unconditional_life", pos)) {
moves_played++;
found_one = 1;
}
}
}
/* Now see whether there are any significant sekis on the board. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!potential_sekis[pos]
|| board[pos] == EMPTY
|| find_origin(pos) != pos)
continue;
for (r = 0; r < 4; r++) {
int up = delta[r];
int right = delta[(r + 1) % 4];
int locally_played_moves = 0;
if (board[pos + up] != color
|| board[pos + up + up] != EMPTY
|| board[pos - up] != EMPTY)
continue;
for (k = 0; k < 2; k++) {
if (k == 1)
right = -right;
if (board[pos + right] != EMPTY || board[pos + up - right] != EMPTY)
continue;
if (board[pos - right] == EMPTY
&& trymove(pos - right, other, "unconditional_life", pos))
locally_played_moves++;
if (board[pos + up + right] == EMPTY
&& trymove(pos + up + right, other, "unconditional_life", pos))
locally_played_moves++;
if (board[pos - right] == other && board[pos + up + right] == other
&& same_string(pos - right, pos + up + right)) {
/* This is a critical seki. Extend the string with one stone
* in an arbitrary direction to break the seki.
*/
while (locally_played_moves > 0) {
popgo();
locally_played_moves--;
}
trymove(pos - up, color, "unconditional_life", pos);
moves_played++;
break;
}
else {
while (locally_played_moves > 0) {
popgo();
locally_played_moves--;
}
}
}
if (countstones(pos) > 2)
break;
}
}
/* Capture the strings involved in potential sekis. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!potential_sekis[pos] || board[pos] == EMPTY)
continue;
/* Play as many liberties as we can. */
liberties = findlib(pos, MAXLIBS, libs);
for (k = 0; k < liberties; k++) {
if (trymove(libs[k], other, "unconditional_life", pos))
moves_played++;
}
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int apos;
int bpos;
int aopen, bopen;
int alib, blib;
if (board[pos] != other || countlib(pos) != 2)
continue;
findlib(pos, 2, libs);
apos = libs[0];
bpos = libs[1];
if (abs(I(apos) - I(bpos)) + abs(J(apos) - J(bpos)) != 1)
continue;
/* Only two liberties and these are adjacent. Play one. We want
* to maximize the number of open liberties. In this particular
* situation we can count this with approxlib for the opposite
* color. If the number of open liberties is the same, we
* maximize the total number of obtained liberties.
* Two relevant positions:
*
* |XXX.
* |OOXX |XXXXXXX
* |O.OX |OOXOOOX
* |..OX |..OO.OX
* +---- +-------
*/
aopen = approxlib(apos, color, 4, NULL);
bopen = approxlib(bpos, color, 4, NULL);
alib = approxlib(apos, other, 4, NULL);
blib = approxlib(bpos, other, 4, NULL);
if (aopen > bopen || (aopen == bopen && alib >= blib)) {
trymove(apos, other, "unconditional_life", pos);
moves_played++;
}
else {
trymove(bpos, other, "unconditional_life", pos);
moves_played++;
}
}
/* Identify unconditionally alive stones and unconditional territory. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] == color && !potential_sekis[pos]) {
unconditional_territory[pos] = 1;
if (find_origin(pos) == pos) {
liberties = findlib(pos, MAXLIBS, libs);
for (k = 0; k < liberties; k++)
unconditional_territory[libs[k]] = 2;
}
}
else if (board[pos] == other && countlib(pos) == 1) {
unconditional_territory[pos] = 2;
findlib(pos, 1, libs);
unconditional_territory[libs[0]] = 2;
}
}
/* Take back all moves. */
while (moves_played > 0) {
popgo();
moves_played--;
}
}
static void
compute_active_reading_area(struct persistent_cache_entry *entry,
const char goal[BOARDMAX], int dummy)
{
signed char active[BOARDMAX];
int pos, r;
UNUSED(dummy);
/* Remains to set the board. We let the active area be the contested
* string and reading shadow + adjacent empty and strings +
* neighbors of active area so far + one more expansion from empty
* to empty.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
active[pos] = goal[pos];
signed_mark_string(entry->apos, active, 1);
/* To be safe, also add the successful move. */
if (entry->result != 0 && entry->move != 0)
active[entry->move] = 1;
/* Add adjacent strings and empty. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
if (active[pos] != 0)
continue;
if ((ON_BOARD(SOUTH(pos)) && active[SOUTH(pos)] == 1)
|| (ON_BOARD(WEST(pos)) && active[WEST(pos)] == 1)
|| (ON_BOARD(NORTH(pos)) && active[NORTH(pos)] == 1)
|| (ON_BOARD(EAST(pos)) && active[EAST(pos)] == 1)) {
if (IS_STONE(board[pos]))
signed_mark_string(pos, active, 2);
else
active[pos] = 2;
}
}
/* Remove invincible strings. No point adding their liberties and
* neighbors.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
if (IS_STONE(board[pos]) && worm[pos].invincible)
active[pos] = 0;
}
/* Expand empty to empty. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (IS_STONE(board[pos]) || active[pos] != 0)
continue;
if ((board[SOUTH(pos)] == EMPTY && active[SOUTH(pos)] == 2)
|| (board[WEST(pos)] == EMPTY && active[WEST(pos)] == 2)
|| (board[NORTH(pos)] == EMPTY && active[NORTH(pos)] == 2)
|| (board[EAST(pos)] == EMPTY && active[EAST(pos)] == 2))
active[pos] = 3;
}
/* Add neighbors of active area so far. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
if (active[pos] != 0)
continue;
if ((ON_BOARD(SOUTH(pos)) && active[SOUTH(pos)] > 0
&& active[SOUTH(pos)] < 4)
|| (ON_BOARD(WEST(pos)) && active[WEST(pos)] > 0
&& active[WEST(pos)] < 4)
|| (ON_BOARD(NORTH(pos)) && active[NORTH(pos)] > 0
&& active[NORTH(pos)] < 4)
|| (ON_BOARD(EAST(pos)) && active[EAST(pos)] > 0
&& active[EAST(pos)] < 4))
active[pos] = 4;
}
/* Also add the previously played stones to the active area. */
for (r = 0; r < stackp; r++)
active[entry->stack[r]] = 5;
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos))
continue;
entry->board[pos] =
active[pos] != 0 ? board[pos] : GRAY;
}
}
static void compute_active_owl_area(struct persistent_cache_entry *entry,
const char goal[BOARDMAX],
int goal_color)
{
int k, r;
int pos;
int other = OTHER_COLOR(goal_color);
signed char active[BOARDMAX];
/* We let the active area be the goal +
* distance four expansion through empty intersections and own stones +
* adjacent opponent strings +
* liberties and neighbors of adjacent opponent strings with less than
* five liberties +
* liberties and neighbors of low liberty neighbors of adjacent opponent
* strings with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos))
active[pos] = (goal[pos] != 0);
/* Also add critical moves to the active area. */
if (ON_BOARD1(entry->move))
active[entry->move] = 1;
if (ON_BOARD1(entry->move2))
active[entry->move2] = 1;
/* Distance four expansion through empty intersections and own stones. */
for (k = 1; k < 5; k++) {
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos) || board[pos] == other || active[pos] > 0)
continue;
if ((ON_BOARD(SOUTH(pos)) && active[SOUTH(pos)] == k)
|| (ON_BOARD(WEST(pos)) && active[WEST(pos)] == k)
|| (ON_BOARD(NORTH(pos)) && active[NORTH(pos)] == k)
|| (ON_BOARD(EAST(pos)) && active[EAST(pos)] == k)) {
if (board[pos] == EMPTY)
active[pos] = k + 1;
else
signed_mark_string(pos, active, (signed char) (k + 1));
}
}
}
/* Adjacent opponent strings. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] != other || active[pos] != 0)
continue;
for (r = 0; r < 4; r++) {
int pos2 = pos + delta[r];
if (ON_BOARD(pos2) && board[pos2] != other && active[pos2] != 0) {
signed_mark_string(pos, active, 1);
break;
}
}
}
/* Liberties of adjacent opponent strings with less than five liberties +
* liberties of low liberty neighbors of adjacent opponent strings
* with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] == other && active[pos] > 0 && countlib(pos) < 5) {
int libs[4];
int liberties = findlib(pos, 4, libs);
int adjs[MAXCHAIN];
int adj;
for (r = 0; r < liberties; r++)
active[libs[r]] = 1;
/* Also add liberties of neighbor strings if these are three
* or less.
*/
adj = chainlinks(pos, adjs);
for (r = 0; r < adj; r++) {
signed_mark_string(adjs[r], active, -1);
if (countlib(adjs[r]) <= 3) {
int s;
int adjs2[MAXCHAIN];
int adj2;
liberties = findlib(adjs[r], 3, libs);
for (s = 0; s < liberties; s++)
active[libs[s]] = 1;
adj2 = chainlinks(pos, adjs2);
for (s = 0; s < adj2; s++)
signed_mark_string(adjs2[s], active, -1);
}
}
}
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int value = board[pos];
if (!ON_BOARD(pos))
continue;
if (!active[pos])
value = GRAY;
else if (IS_STONE(board[pos]) && countlib(pos) > 4 && active[pos] > 0)
value |= HIGH_LIBERTY_BIT;
entry->board[pos] = value;
}
}
void
store_persistent_owl_cache(int routine, int apos, int bpos, int cpos,
int result, int move, int move2, int certain,
int tactical_nodes,
char goal[BOARDMAX], int goal_color)
{
char active[BOARDMAX];
int pos;
int k;
int r;
int other = OTHER_COLOR(goal_color);
gg_assert(stackp == 0);
/* If cache is full, first try to purge it. */
if (persistent_owl_cache_size == MAX_OWL_CACHE_SIZE)
purge_persistent_owl_cache();
/* FIXME: Kick out oldest or least expensive entry instead of giving up. */
if (persistent_owl_cache_size == MAX_OWL_CACHE_SIZE) {
TRACE_OWL_PERFORMANCE("Persistent owl cache full.\n");
return;
}
persistent_owl_cache[persistent_owl_cache_size].boardsize = board_size;
persistent_owl_cache[persistent_owl_cache_size].routine = routine;
persistent_owl_cache[persistent_owl_cache_size].apos = apos;
persistent_owl_cache[persistent_owl_cache_size].bpos = bpos;
persistent_owl_cache[persistent_owl_cache_size].cpos = cpos;
persistent_owl_cache[persistent_owl_cache_size].result = result;
persistent_owl_cache[persistent_owl_cache_size].result_certain = certain;
persistent_owl_cache[persistent_owl_cache_size].move = move;
persistent_owl_cache[persistent_owl_cache_size].move2 = move2;
persistent_owl_cache[persistent_owl_cache_size].tactical_nodes =
tactical_nodes;
persistent_owl_cache[persistent_owl_cache_size].movenum = movenum;
/* Remains to set the board. We let the active area be
* the goal +
* distance four expansion through empty intersections and own stones +
* adjacent opponent strings +
* liberties of adjacent opponent strings with less than five liberties +
* liberties of low liberty neighbors of adjacent opponent strings
* with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos))
active[pos] = (goal[pos] != 0);
/* Also add critical moves to the active area. */
if (ON_BOARD1(move))
active[move] = 1;
if (ON_BOARD1(move2))
active[move2] = 1;
/* Distance four expansion through empty intersections and own stones. */
for (k = 1; k < 5; k++) {
for (pos = BOARDMIN; pos < BOARDMAX; pos++){
if (!ON_BOARD(pos) || board[pos] == other || active[pos] != 0)
continue;
if ((ON_BOARD(SOUTH(pos)) && active[SOUTH(pos)] == k)
|| (ON_BOARD(WEST(pos)) && active[WEST(pos)] == k)
|| (ON_BOARD(NORTH(pos)) && active[NORTH(pos)] == k)
|| (ON_BOARD(EAST(pos)) && active[EAST(pos)] == k)) {
if (board[pos] == EMPTY)
active[pos] = k + 1;
else
mark_string(pos, active, (char) (k + 1));
}
}
}
/* Adjacent opponent strings. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] != other || active[pos] != 0)
continue;
for (r = 0; r < 4; r++) {
int pos2 = pos + delta[r];
if (ON_BOARD(pos2) && board[pos2] != other && active[pos2] != 0) {
mark_string(pos, active, (char) 1);
break;
}
}
}
/* Liberties of adjacent opponent strings with less than five liberties +
* liberties of low liberty neighbors of adjacent opponent strings
* with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] == other && active[pos] != 0 && countlib(pos) < 5) {
int libs[4];
int liberties = findlib(pos, 4, libs);
int adjs[MAXCHAIN];
int adj;
for (r = 0; r < liberties; r++)
active[libs[r]] = 1;
/* Also add liberties of neighbor strings if these are three
* or less.
*/
adj = chainlinks(pos, adjs);
for (r = 0; r < adj; r++) {
if (countlib(adjs[r]) <= 3) {
int s;
liberties = findlib(adjs[r], 3, libs);
for (s = 0; s < liberties; s++)
active[libs[s]] = 1;
}
}
}
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int value = board[pos];
if (!ON_BOARD(pos))
continue;
if (!active[pos])
value = GRAY;
else if (IS_STONE(board[pos]) && countlib(pos) > 4)
value |= HIGH_LIBERTY_BIT;
persistent_owl_cache[persistent_owl_cache_size].board[pos] = value;
}
if (debug & DEBUG_OWL_PERSISTENT_CACHE) {
gprintf("%o Stored result in cache (entry %d):\n",
persistent_owl_cache_size);
print_persistent_owl_cache_entry(persistent_owl_cache_size);
}
persistent_owl_cache_size++;
}
/* Store a new read result in the persistent cache. */
void
store_persistent_reading_cache(int routine, int str, int result, int move,
int nodes)
{
char active[BOARDMAX];
int k;
int r;
int score = nodes;
struct reading_cache *entry;
ASSERT1(result == 0 || (move == 0) || ON_BOARD(move), move);
/* Never cache results at too great depth. */
if (stackp > MAX_READING_CACHE_DEPTH)
return;
/* If cache is still full, consider kicking out an old entry. */
if (persistent_reading_cache_size == MAX_READING_CACHE_SIZE) {
int worst_entry = -1;
int worst_score = score;
for (k = 1; k < persistent_reading_cache_size; k++) {
if (persistent_reading_cache[k].score < worst_score) {
worst_score = persistent_reading_cache[k].score;
worst_entry = k;
}
}
if (worst_entry != -1) {
/* Move the last entry in the cache here to make space.
*/
if (worst_entry < persistent_reading_cache_size - 1)
persistent_reading_cache[worst_entry]
= persistent_reading_cache[persistent_reading_cache_size - 1];
persistent_reading_cache_size--;
}
else
return;
}
entry = &(persistent_reading_cache[persistent_reading_cache_size]);
entry->boardsize = board_size;
entry->movenum = movenum;
entry->nodes = nodes;
entry->score = score;
entry->remaining_depth = depth - stackp;
entry->routine = routine;
entry->str = str;
entry->result = result;
entry->move = move;
for (r = 0; r < MAX_READING_CACHE_DEPTH; r++) {
if (r < stackp)
get_move_from_stack(r, &(entry->stack[r]), &(entry->move_color[r]));
else {
entry->stack[r] = 0;
entry->move_color[r] = EMPTY;
}
}
/* Remains to set the board. We let the active area be the contested
* string and reading shadow + adjacent empty and strings +
* neighbors of active area so far + one more expansion from empty
* to empty.
*/
for (k = BOARDMIN; k < BOARDMAX; k++)
active[k] = shadow[k];
mark_string(str, active, 1);
/* To be safe, also add the successful move. */
if (result != 0 && move != 0)
active[move] = 1;
/* Add adjacent strings and empty. */
for (k = BOARDMIN; k < BOARDMAX; k++) {
if (!ON_BOARD(k))
continue;
if (active[k] != 0)
continue;
if ((ON_BOARD(SOUTH(k)) && active[SOUTH(k)] == 1)
|| (ON_BOARD(WEST(k)) && active[WEST(k)] == 1)
|| (ON_BOARD(NORTH(k)) && active[NORTH(k)] == 1)
|| (ON_BOARD(EAST(k)) && active[EAST(k)] == 1)) {
if (IS_STONE(board[k]))
mark_string(k, active, 2);
else
active[k] = 2;
}
}
/* Remove invincible strings. No point adding their liberties and
* neighbors.
*/
for (k = BOARDMIN; k < BOARDMAX; k++) {
if (!ON_BOARD(k))
continue;
if (IS_STONE(board[k]) && worm[k].invincible)
active[k] = 0;
}
/* Expand empty to empty. */
for (k = BOARDMIN; k < BOARDMAX; k++) {
if (IS_STONE(board[k]) || active[k] != 0)
continue;
if ((board[SOUTH(k)] == EMPTY && active[SOUTH(k)] == 2)
|| (board[WEST(k)] == EMPTY && active[WEST(k)] == 2)
|| (board[NORTH(k)] == EMPTY && active[NORTH(k)] == 2)
|| (board[EAST(k)] == EMPTY && active[EAST(k)] == 2))
active[k] = 3;
}
/* Add neighbors of active area so far. */
for (k = BOARDMIN; k < BOARDMAX; k++) {
if (!ON_BOARD(k))
continue;
if (active[k] != 0)
continue;
if ((ON_BOARD(SOUTH(k)) && active[SOUTH(k)] > 0 && active[SOUTH(k)] < 4)
|| (ON_BOARD(WEST(k)) && active[WEST(k)] > 0 && active[WEST(k)] < 4)
|| (ON_BOARD(NORTH(k)) && active[NORTH(k)] > 0 && active[NORTH(k)] < 4)
|| (ON_BOARD(EAST(k)) && active[EAST(k)] > 0 && active[EAST(k)] < 4))
active[k] = 4;
}
/* Also add the previously played stones to the active area. */
for (r = 0; r < stackp; r++)
active[entry->stack[r]] = 5;
for (k = BOARDMIN; k < BOARDMAX; k++) {
if (!ON_BOARD(k))
continue;
entry->board[k] =
active[k] != 0 ? board[k] : GRAY;
}
if (0) {
gprintf("%o Stored result in cache (entry %d):\n",
persistent_reading_cache_size);
print_persistent_reading_cache_entry(persistent_reading_cache_size);
gprintf("%o Reading shadow was:\n");
draw_reading_shadow();
}
persistent_reading_cache_size++;
}
int
compute_surroundings(int pos, int apos, int showboard, int *surround_size)
{
int i, j;
int m, n;
int k;
int dpos;
int surrounded;
int left_corner[MAX_BOARD];
int right_corner[MAX_BOARD];
int corner[BOARDMAX];
int left_corners = 0, right_corners = 0;
int corners = 0;
int top_row, bottom_row;
int color = board[pos];
int other = OTHER_COLOR(color);
int gi = 0;
int gj = 0;
int stones = 0;
int found_some;
signed char mf[BOARDMAX]; /* friendly dragon */
signed char mn[BOARDMAX]; /* neighbor dragons */
int sd[BOARDMAX]; /* distances to the goal */
if (DRAGON2(pos).hostile_neighbors == 0)
return(0);
memset(mf, 0, sizeof(mf));
memset(mn, 0, sizeof(mn));
memset(sd, 0, sizeof(sd));
mark_dragon(pos, mf, 1);
/* mark hostile neighbors */
for (k = 0; k < DRAGON2(pos).neighbors; k++) {
int nd = DRAGON(DRAGON2(pos).adjacent[k]).origin;
if (board[nd] != color) {
if (0)
gprintf("neighbor: %1m\n", nd);
mark_dragon(nd, mn, 1);
}
}
/* descend markings from stones lying on the 2nd and third lines */
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mn[dpos]) {
for (k = 0; k < 4; k++) {
int d = delta[k];
if (!ON_BOARD(dpos + d))
continue;
if (!ON_BOARD(dpos + 2*d)) {
if (board[dpos + d] == EMPTY)
mn[dpos + d] = 1;
}
else if (!ON_BOARD(dpos + 3*d)) {
if (board[dpos + d] == EMPTY
&& board[dpos + 2*d] == EMPTY)
mn[dpos + 2*d] = 1;
}
}
}
/* compute minimum distances to the goal */
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mn[dpos])
sd[dpos] = goal_dist(dpos, mf);
/* revise markings */
do {
found_some = 0;
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mn[dpos] && sd[dpos] > 8) {
/* discard markings if we can find 2 stones
* that verify :
* - it is closer to the goal than we are
* - it is closer to us than the goal is
* - they are closer to each other than we are to the goal
*/
for (i = BOARDMIN; i < BOARDMAX; i++)
if (ON_BOARD(i) && mn[i] && i != dpos
&& sd[i] < sd[dpos]
&& square_dist(i, dpos) < sd[dpos]) {
for (j = i + 1; j < BOARDMAX; j++)
if (ON_BOARD(j) && mn[j] && j != dpos
&& sd[j] < sd[dpos]
&& square_dist(j, dpos) < sd[dpos]
&& square_dist(i, j) < sd[dpos]) {
mn[dpos] = 0;
found_some = 1;
break;
}
if (mn[dpos] == 0)
break;
}
}
} while (found_some);
/* prepare corner array */
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mn[dpos])
corner[corners++] = dpos;
/* compute gravity center of the goal */
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mf[dpos]) {
gi += I(dpos);
gj += J(dpos);
stones++;
}
gi /= stones;
gj /= stones;
gg = POS(gi, gj);
/* sort the corner array */
gg_sort(corner, corners, sizeof(int), compare_angles);
/* if apos is not NO_MOVE, mark it. */
if (apos != NO_MOVE) {
ASSERT_ON_BOARD1(apos);
mn[apos] = 1;
}
if (showboard == 1) {
show_surround_map(mf, mn);
}
/* find top row of surrounding polyhedron */
top_row = -1;
for (m = 0; m < board_size; m++) {
if (top_row != -1)
break;
for (n = 0; n < board_size; n++)
if (mn[POS(m, n)]) {
left_corner[0] = POS(m, n);
top_row = m;
break;
}
}
/* find bottom row */
bottom_row = -1;
for (m = board_size - 1; m >= 0; m--) {
if (bottom_row != -1)
break;
for (n = 0; n < board_size; n++)
if (mn[POS(m, n)]) {
bottom_row = m;
break;
}
}
/* find the corners on the left side */
for (left_corners = 1; I(left_corner[left_corners-1]) < bottom_row;
left_corners++) {
int best_found = 0;
float best_slope = 0.;
int m = I(left_corner[left_corners-1]);
int n = J(left_corner[left_corners-1]);
for (i = m + 1; i <= bottom_row; i++)
for (j = 0; j < board_size; j++)
if (mn[POS(i, j)]) {
float slope = ((float) (j - n))/((float) (i - m));
if (0)
gprintf("(left) at %m, last %m, slope=%f\n", i, j, m, n, slope);
if (!best_found || slope < best_slope) {
best_found = POS(i, j);
best_slope = slope;
}
}
ASSERT_ON_BOARD1(best_found);
left_corner[left_corners] = best_found;
}
for (n = board_size-1; n >= 0; n--)
if (mn[POS(top_row, n)]) {
right_corner[0] = POS(top_row, n);
break;
}
/* find the corners on the right side */
for (right_corners = 1; I(right_corner[right_corners-1]) < bottom_row;
right_corners++) {
int best_found = 0;
float best_slope = 0.;
int m = I(right_corner[right_corners-1]);
int n = J(right_corner[right_corners-1]);
for (i = m + 1; i <= bottom_row; i++) {
for (j = board_size - 1; j >= 0; j--) {
if (mn[POS(i, j)]) {
float slope = ((float) (j - n))/((float) (i - m));
if (0)
gprintf("(right) at %m, last %m, slope=%f\n", i, j, m, n, slope);
if (!best_found || slope > best_slope) {
best_found = POS(i, j);
best_slope = slope;
}
}
}
}
ASSERT_ON_BOARD1(best_found);
right_corner[right_corners] = best_found;
}
if (0) {
for (k = 0; k < left_corners; k++)
gprintf("left corner %d: %1m\n", k, left_corner[k]);
for (k = 0; k < right_corners; k++)
gprintf("right corner %d: %1m\n", k, right_corner[k]);
}
/* Now mark the interior of the convex hull */
for (n = J(left_corner[0]); n <= J(right_corner[0]); n++)
mn[POS(top_row, n)] = 1;
for (n = J(left_corner[left_corners-1]);
n <= J(right_corner[right_corners-1]); n++)
mn[POS(bottom_row, n)] = 1;
for (m = top_row+1; m < bottom_row; m++) {
int left_boundary = -1, right_boundary = -1;
for (k = 1; k < left_corners; k++) {
if (I(left_corner[k]) > m) {
float ti = I(left_corner[k-1]);
float tj = J(left_corner[k-1]);
float bi = I(left_corner[k]);
float bj = J(left_corner[k]);
if (0)
gprintf("(left) %d: %1m %1m\n",
m, left_corner[k-1], left_corner[k]);
/* left edge in this row is on segment (ti,tj) -> (bi, bj) */
/* FIXME: Rewrite this to avoid floating point arithmetic */
left_boundary = ceil(tj + (m - ti) * (bj - tj) / (bi - ti));
break;
}
}
for (k = 1; k < right_corners; k++) {
if (I(right_corner[k]) > m) {
float ti = I(right_corner[k-1]);
float tj = J(right_corner[k-1]);
float bi = I(right_corner[k]);
float bj = J(right_corner[k]);
if (0)
gprintf("(right) %d: %1m %1m\n",
m, right_corner[k-1], right_corner[k]);
/* FIXME: Rewrite this to avoid floating point arithmetic */
right_boundary = floor(tj + (m - ti) * (bj - tj) / (bi - ti));
break;
}
}
for (n = left_boundary; n <= right_boundary; n++)
mn[POS(m, n)] = 1;
}
/* mark the expanded region */
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (ON_BOARD(dpos) && mn[dpos] == 1)
for (k = 0; k < 4; k++)
if (ON_BOARD(dpos + delta[k]) && !mn[dpos + delta[k]])
mn[dpos + delta[k]] = 2;
/* Mark allied dragons that intersect the (unexpanded) hull.
* These must all lie entirely within the hull for the
* dragon to be considered surrounded.
*
* Only neighbor dragons are considered since dragons that
* are not neighbors are less likely to be helpful.
*/
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++) {
int mpos;
if (ON_BOARD(dpos)
&& mn[dpos] == 1
&& board[dpos] == color
&& are_neighbor_dragons(pos, dpos)
&& !mf[dpos]) {
for (mpos = BOARDMIN; mpos < BOARDMAX; mpos++)
if (ON_BOARD(mpos) && is_same_dragon(mpos, dpos))
mf[mpos] = 2;
}
/* A special case
*
* . X X .
* X O . X
* X . O O
* . O . .
*
* The O stone hasn't been amalgamated and the surround computations
* might think this single stone dragon is surrounded, which in turn
* can generate overvaluation of moves around this stone.
* Consequently, we allow inclusion of the stones at kosumi distance
* in the mf (friendly) array.
*/
if (ON_BOARD(dpos)
&& mn[dpos] == 2
&& board[dpos] == color
&& are_neighbor_dragons(pos, dpos)
&& !mf[dpos]) {
for (k = 4; k < 8; k++)
if (ON_BOARD(dpos + delta[k]) && board[dpos + delta[k]] == color
&& mn[dpos + delta[k]] == 1
&& board[dpos + delta[k-4]] == EMPTY
&& board[dpos + delta[(k-3)%4]] == EMPTY) {
for (mpos = BOARDMIN; mpos < BOARDMAX; mpos++)
if (ON_BOARD(mpos) && is_same_dragon(mpos, dpos))
mf[mpos] = 2;
}
}
}
/* determine the surround status of the dragon */
surrounded = SURROUNDED;
/* Compute the maximum surround status awarded
* If distances between enclosing stones are large, reduce to
* WEAKLY_SURROUNDED. If (really) too large, then reduce to 0
* FIXME: constants chosen completely ad hoc. Possibly better tunings
* can be found.
*/
for (k = 0; k < corners - 1; k++) {
if (is_edge_vertex(corner[k])
&& is_edge_vertex(corner[k+1]))
continue;
if (square_dist(corner[k], corner[k+1]) > 60) {
surrounded = 0;
break;
}
else if (square_dist(corner[k], corner[k+1]) > 27)
surrounded = WEAKLY_SURROUNDED;
}
if (surrounded
&& (!is_edge_vertex(corner[0])
|| !is_edge_vertex(corner[corners-1]))) {
if (square_dist(corner[0], corner[corners-1]) > 60)
surrounded = 0;
else if (square_dist(corner[0], corner[corners-1]) > 27)
surrounded = WEAKLY_SURROUNDED;
}
if (surrounded)
for (dpos = BOARDMIN; dpos < BOARDMAX; dpos++)
if (mf[dpos]) {
if (mn[dpos] == 0) {
surrounded = 0;
break;
}
else if (mn[dpos] == 2)
surrounded = WEAKLY_SURROUNDED;
}
/* revise the status for single stone dragons. */
if (stones == 1
&& surrounded == WEAKLY_SURROUNDED
&& mn[pos] == 2)
surrounded = 0;
/* revise the status if an ikken tobi jumps out. */
if (surrounded) {
for (dpos = BOARDMIN; dpos < BOARDMAX && surrounded; dpos++) {
if (!ON_BOARD(dpos) || !mf[dpos])
continue;
for (k = 0; k < 4; k++) {
int up = delta[k];
int right = delta[(k + 1) % 4];
if (board[dpos + up] == EMPTY
&& board[dpos + 2*up] == color
&& mn[dpos + 2*up] != 1
&& ON_BOARD(dpos + up + right)
&& board[dpos + up + right] != other
&& ON_BOARD(dpos + up - right)
&& board[dpos + up - right] != other) {
surrounded = 0;
break;
}
}
}
}
if (showboard == 1 || (showboard == 2 && surrounded)) {
show_surround_map(mf, mn);
}
if (!apos && surrounded && surround_pointer < MAX_SURROUND) {
memcpy(surroundings[surround_pointer].surround_map, mn, sizeof(mn));
surroundings[surround_pointer].dragon_number = dragon[pos].id;
surround_pointer++;
}
if (surround_size) {
int pos;
*surround_size = 0;
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos) && mn[pos] == 1)
(*surround_size)++;
}
return surrounded;
}
/* Computes the active area for the current board position and the
* read result that has just been stored in *entry.
*/
static void
compute_active_breakin_area(struct persistent_cache_entry *entry,
const char breakin_shadow[BOARDMAX], int dummy)
{
int pos;
int k, r;
signed char active[BOARDMAX];
int other = OTHER_COLOR(board[entry->apos]);
UNUSED(dummy);
/* We let the active area be
* the string to connect +
* the breakin shadow (which contains the goal) +
* distance two expansion through empty intersections and own stones +
* adjacent opponent strings +
* liberties and neighbors of adjacent opponent strings with less than
* five liberties +
* liberties and neighbors of low liberty neighbors of adjacent opponent
* strings with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
active[pos] = breakin_shadow[pos];
signed_mark_string(entry->apos, active, 1);
/* To be safe, also add the successful move. */
if (entry->result != 0 && entry->move != 0)
active[entry->move] = 1;
/* Distance two expansion through empty intersections and own stones. */
for (k = 1; k < 3; k++) {
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (!ON_BOARD(pos) || board[pos] == other || active[pos] != 0)
continue;
if ((ON_BOARD(SOUTH(pos)) && active[SOUTH(pos)] == k)
|| (ON_BOARD(WEST(pos)) && active[WEST(pos)] == k)
|| (ON_BOARD(NORTH(pos)) && active[NORTH(pos)] == k)
|| (ON_BOARD(EAST(pos)) && active[EAST(pos)] == k)) {
if (board[pos] == EMPTY)
active[pos] = k + 1;
else
signed_mark_string(pos, active, (signed char) (k + 1));
}
}
}
/* Adjacent opponent strings. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] != other || active[pos] != 0)
continue;
for (r = 0; r < 4; r++) {
int pos2 = pos + delta[r];
if (ON_BOARD(pos2)
&& board[pos2] != other
&& active[pos2] && active[pos2] <= 2) {
signed_mark_string(pos, active, 1);
break;
}
}
}
/* Liberties of adjacent opponent strings with less than four liberties +
* liberties of low liberty neighbors of adjacent opponent strings
* with less than five liberties.
*/
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (board[pos] == other && active[pos] > 0 && countlib(pos) < 4) {
int libs[4];
int liberties = findlib(pos, 3, libs);
int adjs[MAXCHAIN];
int adj;
for (r = 0; r < liberties; r++)
active[libs[r]] = 1;
/* Also add liberties of neighbor strings if these are three
* or less.
*/
adj = chainlinks(pos, adjs);
for (r = 0; r < adj; r++) {
signed_mark_string(adjs[r], active, -1);
if (countlib(adjs[r]) <= 3) {
int s;
int adjs2[MAXCHAIN];
int adj2;
liberties = findlib(adjs[r], 3, libs);
for (s = 0; s < liberties; s++)
active[libs[s]] = 1;
adj2 = chainlinks(pos, adjs2);
for (s = 0; s < adj2; s++)
signed_mark_string(adjs2[s], active, -1);
}
}
}
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
char value = board[pos];
if (!ON_BOARD(pos))
continue;
if (!active[pos])
value = GRAY;
else if (IS_STONE(board[pos]) && countlib(pos) > 3 && active[pos] > 0)
value |= HIGH_LIBERTY_BIT2;
entry->board[pos] = value;
}
}