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pygo/gnugo/engine/montecarlo.c

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* This is GNU Go, a Go program. Contact gnugo@gnu.org, or see *
* http://www.gnu.org/software/gnugo/ for more information. *
* *
* Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, *
* 2008 and 2009 by the Free Software Foundation. *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation - version 3 or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License in file COPYING for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program; if not, write to the Free *
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, *
* Boston, MA 02111, USA. *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include "gnugo.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "liberty.h"
#include "sgftree.h"
#include "gg_utils.h"
#include "random.h"
#include <math.h>
/* FIXME: Replace with a DEBUG_MC symbol for use with -d. */
static int mc_debug = 0;
#define TURN_OFF_ASSERTIONS 1
/* Special board code for Monte Carlo simulations.
*
* A liberty edge is the combination of the position of the liberty
* and the direction to a string given by the index into the delta[]
* array. A liberty edge at lib with corresponding string in direction
* delta[dir] is encoded as (lib << 2 | dir).
*
* The stones of a string are linked in a cyclic list through the
* next_stone field, just like the global board does.
*
* Likewise the liberty edges corresponding to each string are
* connected in a doubly linked cyclic list through the
* previous_liberty_edge and next_liberty_edge fields.
*
* The reference stone has to be the same for every stone in a string
* but it doesn't have to be a predictable one, in contrast to the
* origin in the global board. The reference stone is the only one
* which is guaranteed to have a valid pointer to the "first" liberty
* edge (just an arbitrary element in the circular list).
*
* The local_context field contains information about the surrounding
* 8 points. The bit layout is
*
* 23 : Black suicide.
* 22 : White suicide.
* 21 : Black self-atari.
* 20 : White self-atari.
* 19,18: Number of stones captured by black move.
* 17,16: Number of stones captured by white move.
* 15,14: Color to the southeast.
* 13,12: Color to the northeast.
* 11,10: Color to the northwest.
* 9, 8: Color to the southwest.
* 7, 6: Color to the east.
* 5, 4: Color to the north.
* 3, 2: Color to the west.
* 1, 0: Color to the south.
*
* The number of stones in atari is 0 if empty or not atari, 1 if one
* stone in atari, 2 if two stones in atari, and 3 if three or more stones
* in atari.
*
* The queue array is used to form a linked single list data structure
* with O(1) add, O(1) lookup, and O(n) delete operations. The
* assumption is that v1 = queue[0] points to the first board vertex
* in the list, v2 = queue[v1] points to the second vertex and so on.
* The list ends when the next vertex is the off-board point 1. Board
* vertices not included in the list have queue[v1] = 0. Thus an empty
* list is characterized by queue[0] = 1 and queue[v] = 0 for all
* vertices on the board. Generally queue[v] can be used to test for
* membership in the list. The list is used to keep track of points
* needing updated local context or value information.
*
* The move_values_*, partitioned_move_value_sums_*,
* move_partition_lists_*, and move_value_sum_* fields are together
* used to track move values and quickly sample according the
* distribution determined by the move values.
*
* The move_values_* arrays naturally hold the values of each move.
*
* The move_partition_lists_* arrays form a two-level access to the
* legal moves of respective color. Depending on the MAX_BOARD size,
* the vertices are split into 2, 4, 8, or 16 partitions (see below)
* where the partition number of each vertex is given by the 1, 2, 3,
* or 4 least significant bits of the vertex index respectively. The
* legal moves in each partition are linked together just like the
* queue array described above. The only difference is that multiple
* partition linked lists are represented in the same array by
* starting from out of board indices 0..1, 0..3, 0..7, and 0..15
* respectively.
*
* The partitioned_move_value_sums_* arrays are simply the sums of
* move values in each partition and the move_value_sum_white_* fields
* are the sum of the values of all legal moves.
*/
#if MAX_BOARD < 4
#define NUM_MOVE_PARTITIONS 2
#elif MAX_BOARD < 8
#define NUM_MOVE_PARTITIONS 4
#elif MAX_BOARD < 16
#define NUM_MOVE_PARTITIONS 8
#else
#define NUM_MOVE_PARTITIONS 16
#endif
struct mc_board {
Intersection board[BOARDSIZE];
int local_context[BOARDSIZE];
int queue[BOARDMAX];
unsigned int move_values_white[BOARDMAX];
unsigned int move_values_black[BOARDMAX];
unsigned int partitioned_move_value_sums_white[NUM_MOVE_PARTITIONS];
unsigned int partitioned_move_value_sums_black[NUM_MOVE_PARTITIONS];
int move_partition_lists_white[BOARDMAX];
int move_partition_lists_black[BOARDMAX];
unsigned int move_value_sum_white;
unsigned int move_value_sum_black;
int board_ko_pos;
int reference_stone[BOARDMAX];
int next_stone[BOARDMAX];
int first_liberty_edge[BOARDMAX];
int previous_liberty_edge[4 * BOARDMAX];
int next_liberty_edge[4 * BOARDMAX];
Hash_data hash;
};
#define MC_ADD_TO_UPDATE_QUEUE(mc, pos) \
do { \
if (!mc->queue[pos]) { \
mc->queue[pos] = mc->queue[0]; \
mc->queue[0] = pos; \
} \
} while (0)
#define MC_ON_BOARD(pos) (mc->board[pos] != GRAY)
/* Add a liberty edge for a string at pos with liberty at lib and
* direction dir.
*/
static void
mc_add_liberty_edge(struct mc_board *mc, int pos, int lib, int dir)
{
int this_liberty_edge = (lib << 2) | dir;
int reference = mc->reference_stone[pos];
int first_liberty_edge = mc->first_liberty_edge[reference];
#if !TURN_OFF_ASSERTIONS
gg_assert(lib + delta[dir] == pos);
#endif
if (first_liberty_edge) {
int second_liberty_edge = mc->next_liberty_edge[first_liberty_edge];
mc->previous_liberty_edge[this_liberty_edge] = first_liberty_edge;
mc->next_liberty_edge[this_liberty_edge] = second_liberty_edge;
mc->next_liberty_edge[first_liberty_edge] = this_liberty_edge;
mc->previous_liberty_edge[second_liberty_edge] = this_liberty_edge;
}
else {
mc->first_liberty_edge[reference] = this_liberty_edge;
mc->next_liberty_edge[this_liberty_edge] = this_liberty_edge;
mc->previous_liberty_edge[this_liberty_edge] = this_liberty_edge;
}
}
/* Remove a liberty edge for a string at pos with liberty at lib and
* direction dir.
*/
static int
mc_remove_liberty_edge(struct mc_board *mc, int pos, int lib, int dir)
{
int reference = mc->reference_stone[pos];
int this_liberty_edge = (lib << 2) | dir;
int next = mc->next_liberty_edge[this_liberty_edge];
int previous = mc->previous_liberty_edge[this_liberty_edge];
#if !TURN_OFF_ASSERTIONS
gg_assert(lib + delta[dir] == pos);
#endif
if (next == this_liberty_edge) {
mc->first_liberty_edge[reference] = 0;
return 0;
}
mc->next_liberty_edge[previous] = next;
mc->previous_liberty_edge[next] = previous;
if (mc->first_liberty_edge[reference] == this_liberty_edge)
mc->first_liberty_edge[reference] = next;
return next;
}
/* Join the strings at str1 and str2. It is assumed that str1 is a
* newly placed stone (possibly already joined with other strings) and
* that the liberty edge corresponding to the liberty at the newly
* placed stone has not yet been removed.
*/
static void
mc_join_strings(struct mc_board *mc, int str1, int str2)
{
int reference = mc->reference_stone[str2];
int liberty_edge2 = mc->first_liberty_edge[reference];
int liberty_edge1 = mc->first_liberty_edge[mc->reference_stone[str1]];
int next1;
int next2;
int pos = str1;
/* Update the reference stone for str1. */
do {
mc->reference_stone[pos] = reference;
pos = mc->next_stone[pos];
} while (pos != str1);
/* Switch next_stone pointers to join the strings. */
next1 = mc->next_stone[str1];
mc->next_stone[str1] = mc->next_stone[str2];
mc->next_stone[str2] = next1;
/* Join the circular liberty_edge structures. We know that str2
* still has a liberty listed at the newly added stone so
* liberty_edge2 is guaranteed to be non-zero.
*/
if (liberty_edge1 != 0) {
next1 = mc->next_liberty_edge[liberty_edge1];
next2 = mc->next_liberty_edge[liberty_edge2];
mc->next_liberty_edge[liberty_edge1] = next2;
mc->next_liberty_edge[liberty_edge2] = next1;
mc->previous_liberty_edge[next1] = liberty_edge2;
mc->previous_liberty_edge[next2] = liberty_edge1;
}
}
/* Does the string at str have at most two liberties? In that case,
* add them to the update queue.
*/
static void
mc_queue_max_two_liberties(struct mc_board *mc, int str)
{
int reference = mc->reference_stone[str];
int first_liberty_edge = mc->first_liberty_edge[reference];
int first_liberty = first_liberty_edge >> 2;
int liberty_edge = mc->next_liberty_edge[first_liberty_edge];
int second_liberty;
#if !TURN_OFF_ASSERTIONS
ASSERT1(IS_STONE(mc->board[str]), str);
#endif
if (first_liberty == NO_MOVE)
return;
while (liberty_edge != first_liberty_edge) {
if ((liberty_edge >> 2) != first_liberty) {
second_liberty = liberty_edge >> 2;
while (liberty_edge != first_liberty_edge) {
if ((liberty_edge >> 2) != first_liberty
&& (liberty_edge >> 2) != second_liberty)
return;
liberty_edge = mc->next_liberty_edge[liberty_edge];
}
MC_ADD_TO_UPDATE_QUEUE(mc, first_liberty);
MC_ADD_TO_UPDATE_QUEUE(mc, second_liberty);
return;
}
liberty_edge = mc->next_liberty_edge[liberty_edge];
}
MC_ADD_TO_UPDATE_QUEUE(mc, first_liberty);
}
/* Remove the string at str from the board. */
static int
mc_remove_string(struct mc_board *mc, int str)
{
int color = mc->board[str];
int other = OTHER_COLOR(color);
int pos = str;
int num_removed_stones = 0;
int k;
do {
for (k = 0; k < 8; k++) {
if (k < 4 && mc->board[pos + delta[k]] == other) {
mc_queue_max_two_liberties(mc, pos + delta[k]);
mc_add_liberty_edge(mc, pos + delta[k], pos, k);
}
if (mc->board[pos + delta[k]] == EMPTY)
MC_ADD_TO_UPDATE_QUEUE(mc, pos + delta[k]);
}
mc->board[pos] = EMPTY;
mc->local_context[NW(pos)] ^= color << 14;
mc->local_context[SW(pos)] ^= color << 12;
mc->local_context[SE(pos)] ^= color << 10;
mc->local_context[NE(pos)] ^= color << 8;
mc->local_context[WEST(pos)] ^= color << 6;
mc->local_context[SOUTH(pos)] ^= color << 4;
mc->local_context[EAST(pos)] ^= color << 2;
mc->local_context[NORTH(pos)] ^= color;
hashdata_invert_stone(&(mc->hash), pos, color);
MC_ADD_TO_UPDATE_QUEUE(mc, pos);
num_removed_stones++;
pos = mc->next_stone[pos];
} while (pos != str);
return num_removed_stones;
}
/* Initialize a Monte Carlo board struct from the global board. */
static void
mc_init_board_from_global_board(struct mc_board *mc)
{
int stones[BOARDMAX];
int num_stones;
int pos;
int k;
int r;
memcpy(mc->board, board, sizeof(mc->board));
mc->board_ko_pos = board_ko_pos;
mc->hash = board_hash;
memset(mc->queue, 0, sizeof(mc->queue));
mc->queue[0] = 1;
memset(mc->next_stone, 0, sizeof(mc->next_stone));
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
int geometry = ((mc->board[SE(pos)] << 14)
| (mc->board[NE(pos)] << 12)
| (mc->board[NW(pos)] << 10)
| (mc->board[SW(pos)] << 8)
| (mc->board[EAST(pos)] << 6)
| (mc->board[NORTH(pos)] << 4)
| (mc->board[WEST(pos)] << 2)
| mc->board[SOUTH(pos)]);
mc->local_context[pos] = geometry;
if (board[pos] == EMPTY) {
int s;
int captured_black_stones = 0;
int captured_white_stones = 0;
if (is_self_atari(pos, WHITE))
mc->local_context[pos] |= 1 << 20;
if (is_self_atari(pos, BLACK))
mc->local_context[pos] |= 1 << 21;
if (is_suicide(pos, WHITE))
mc->local_context[pos] |= 1 << 22;
if (is_suicide(pos, BLACK))
mc->local_context[pos] |= 1 << 23;
for (s = 0; s < 4; s++) {
if (board[pos + delta[s]] == BLACK
&& countlib(pos + delta[s]) == 1)
captured_black_stones += countstones(pos + delta[s]);
else if (board[pos + delta[s]] == WHITE
&& countlib(pos + delta[s]) == 1)
captured_white_stones += countstones(pos + delta[s]);
}
if (captured_black_stones > 3)
captured_black_stones = 3;
if (captured_white_stones > 3)
captured_white_stones = 3;
mc->local_context[pos] |= captured_black_stones << 16;
mc->local_context[pos] |= captured_white_stones << 18;
}
if (IS_STONE(board[pos]) && mc->next_stone[pos] == 0) {
num_stones = findstones(pos, BOARDMAX, stones);
mc->first_liberty_edge[pos] = 0;
for (r = 0; r < num_stones; r++) {
mc->next_stone[stones[r]] = stones[(r + 1) % num_stones];
mc->reference_stone[stones[r]] = pos;
for (k = 0; k < 4; k++) {
if (board[stones[r] + delta[k]] == EMPTY)
mc_add_liberty_edge(mc, stones[r], stones[r] + delta[k],
(k + 2) % 4);
}
}
}
}
}
#if 0
/* Debug tool. */
static void
mc_check_consistency_with_global_board(struct mc_board *mc)
{
int pos;
ASSERT1(board_ko_pos == mc->board_ko_pos, mc->board_ko_pos);
for (pos = 0; pos < BOARDSIZE; pos++) {
ASSERT1(board[pos] == mc->board[pos], pos);
if (IS_STONE(board[pos])) {
ASSERT1(same_string(pos, mc->reference_stone[pos]), pos);
if (find_origin(pos) == pos) {
int reference = mc->reference_stone[pos];
int pos2 = pos;
int num_stones = 0;
int first_liberty_edge;
int liberty_edge;
int num_liberty_edges = 0;
int k;
int ml[4 * BOARDMAX];
memset(ml, 0, sizeof(ml));
do {
ASSERT1(mc->reference_stone[pos2] == reference, pos2);
ASSERT1(num_stones < countstones(pos), pos);
num_stones++;
for (k = 0; k < 4; k++)
if (board[pos2 + delta[k]] == EMPTY) {
ml[(pos2 + delta[k]) << 2 | (k + 2) % 4] = 1;
num_liberty_edges++;
}
pos2 = mc->next_stone[pos2];
} while (pos2 != pos);
ASSERT1(num_stones == countstones(pos), pos);
first_liberty_edge = mc->first_liberty_edge[reference];
liberty_edge = first_liberty_edge;
do {
int previous = mc->previous_liberty_edge[liberty_edge];
int next = mc->next_liberty_edge[liberty_edge];
ASSERT1(ml[liberty_edge] == 1, pos);
ml[liberty_edge] = 0;
num_liberty_edges--;
ASSERT1(mc->next_liberty_edge[previous] == liberty_edge, pos);
ASSERT1(mc->previous_liberty_edge[next] == liberty_edge, pos);
ASSERT1(liberty_of_string(liberty_edge >> 2, pos), pos);
liberty_edge = mc->next_liberty_edge[liberty_edge];
} while (liberty_edge != first_liberty_edge);
ASSERT1(num_liberty_edges == 0, pos);
}
}
}
}
#endif
/* Write the Monte Carlo board to outfile. */
static void
mc_showboard(struct mc_board *mc, FILE *outfile)
{
int i, j;
draw_letter_coordinates(outfile);
for (i = 0; i < board_size; i++) {
fprintf(outfile, "\n%2d", board_size - i);
for (j = 0; j < board_size; j++) {
if (mc->board[POS(i, j)] == EMPTY)
fprintf(outfile, " %c", is_hoshi_point(i, j) ? '+' : '.');
else
fprintf(outfile, " %c", mc->board[POS(i, j)] == BLACK ? 'X' : 'O');
}
}
fprintf(outfile, "\n");
draw_letter_coordinates(outfile);
}
/* Count the number of stones in the string at str. Stop counting if
* maxstones is reached.
*/
static int
mc_countstones(struct mc_board *mc, int str, int maxstones)
{
int stone = str;
int num_stones = 0;
do {
num_stones++;
stone = mc->next_stone[stone];
} while (stone != str && num_stones < maxstones);
return num_stones;
}
/* Suicide is incrementally tracked by the local context information. */
#define mc_is_suicide(mc, pos, color) \
((mc->local_context[pos] >> (21 + color)) & 1)
#if !TURN_OFF_ASSERTIONS
/* Is a move at pos by color legal? */
static int
mc_is_legal(struct mc_board *mc, int pos, int color)
{
if (pos == PASS_MOVE)
return 1;
if (mc->board[pos] != EMPTY)
return 0;
if (pos == mc->board_ko_pos) {
if (mc->board[WEST(pos)] == OTHER_COLOR(color)
|| mc->board[EAST(pos)] == OTHER_COLOR(color)) {
return 0;
}
}
return !mc_is_suicide(mc, pos, color);
}
#endif
/* Is the string at str in atari? Always place one liberty of the
* string in lib, unless it's a null pointer.
*/
static int
mc_is_in_atari(struct mc_board *mc, int str, int *lib)
{
int reference = mc->reference_stone[str];
int first_liberty_edge = mc->first_liberty_edge[reference];
int liberty = first_liberty_edge >> 2;
int liberty_edge = mc->next_liberty_edge[first_liberty_edge];
#if !TURN_OFF_ASSERTIONS
ASSERT1(IS_STONE(mc->board[str]), str);
#endif
if (lib)
*lib = liberty;
while (liberty_edge != first_liberty_edge) {
if ((liberty_edge >> 2) != liberty)
return 0;
liberty_edge = mc->next_liberty_edge[liberty_edge];
}
return 1;
}
/* Does the liberty edge chain at first_liberty_edge contain more than
* one distinct liberty?
*/
static int
mc_is_in_atari2(struct mc_board *mc, int first_liberty, int first_liberty_edge)
{
int liberty_edge = mc->next_liberty_edge[first_liberty_edge];
while (liberty_edge != first_liberty_edge) {
if ((liberty_edge >> 2) != first_liberty)
return 0;
liberty_edge = mc->next_liberty_edge[liberty_edge];
}
return 1;
}
/* Count the number of stones that would be captured if color played at move.
* Return at most the number given by maxstones.
*/
static int
mc_stones_in_atari(struct mc_board *mc, int move, int color, int maxstones)
{
int k;
int stones_in_atari = 0;
for (k = 0; k < 4 && stones_in_atari < maxstones; k++) {
int pos = move + delta[k];
if (mc->board[pos] == OTHER_COLOR(color)
&& mc_is_in_atari(mc, pos, NULL))
stones_in_atari += mc_countstones(mc, pos, maxstones - stones_in_atari);
}
return stones_in_atari;
}
/* Does the string at str have exactly two liberties? One liberty is
* assumed to be known and passed in first_liberty, whereas the second
* is placed in second_liberty.
*/
static int
mc_has_two_liberties_one_given(struct mc_board *mc, int str,
int first_liberty, int *second_liberty)
{
int reference = mc->reference_stone[str];
int first_liberty_edge = mc->first_liberty_edge[reference];
int liberty_edge = first_liberty_edge;
*second_liberty = NO_MOVE;
do {
int liberty = liberty_edge >> 2;
if (liberty != first_liberty) {
if (*second_liberty == NO_MOVE)
*second_liberty = liberty;
else if (liberty != *second_liberty)
return 0;
}
liberty_edge = mc->next_liberty_edge[liberty_edge];
} while (liberty_edge != first_liberty_edge);
return (*second_liberty != NO_MOVE);
}
/* Is a move at pos by color a self atari? */
static int
mc_is_self_atari(struct mc_board *mc, int pos, int color)
{
int k;
int captured = NO_MOVE;
int liberty = NO_MOVE;
int reference;
int other;
/* Quick test which is often effective. */
if (((mc->board[SOUTH(pos)] == EMPTY)
+ (mc->board[WEST(pos)] == EMPTY)
+ (mc->board[NORTH(pos)] == EMPTY)
+ (mc->board[EAST(pos)] == EMPTY)) > 1)
return 0;
/* Otherwise look closer. */
for (k = 0; k < 4; k++) {
int first_liberty_edge;
int liberty_edge;
int additional_liberty = 0;
int pos2 = pos + delta[k];
if (mc->board[pos2] == EMPTY) {
if (pos2 != liberty) {
if (liberty != NO_MOVE)
return 0;
else
liberty = pos2;
}
}
else if (IS_STONE(mc->board[pos2])) {
first_liberty_edge = (pos << 2) | k;
liberty_edge = mc->next_liberty_edge[first_liberty_edge];
while (liberty_edge != first_liberty_edge) {
int lib = liberty_edge >> 2;
if (lib != pos) {
additional_liberty = 1;
if (mc->board[pos2] == color) {
if (lib != liberty) {
if (liberty != NO_MOVE)
return 0;
else
liberty = lib;
}
}
else
break;
}
liberty_edge = mc->next_liberty_edge[liberty_edge];
}
if (mc->board[pos2] != color && additional_liberty == 0) {
captured = pos2;
if (pos2 != liberty) {
if (liberty != NO_MOVE)
return 0;
else
liberty = pos2;
}
}
}
}
if (liberty == NO_MOVE || captured == NO_MOVE)
return 1;
/* Now only the difficult case remains where there was no adjacent
* empty stone, no adjacent friendly stone with an extra liberty,
* and exactly one neighbor was captured. Then the question is
* whether the capture produced a second liberty elsewhere.
*/
reference = mc->reference_stone[captured];
other = OTHER_COLOR(color);
for (k = 0; k < 4; k++) {
if (mc->board[pos + delta[k]] == color) {
int stone = pos + delta[k];
do {
int m;
for (m = 0; m < 4; m++) {
int pos2 = stone + delta[m];
if (mc->board[pos2] == other
&& pos2 != captured
&& mc->reference_stone[pos2] == reference)
return 0;
}
stone = mc->next_stone[stone];
} while (stone != pos + delta[k]);
}
}
return 1;
}
/* Update the local context information at pos, except the geometric
* information, by recomputing it. Most of the information is obtained
* by analyzing the presence of empty vertices or stones in atari
* adjacent to pos.
*
* FIXME: There's some computations wasted by calling the full
* mc_is_self_atari() and mc_stones_in_atari() functions when parts of
* the relevant information is already available.
*/
static void
mc_update_local_context(struct mc_board *mc, int pos)
{
int min_white_liberties = 0;
int min_black_liberties = 0;
int white_liberty_through_stones = 0;
int black_liberty_through_stones = 0;
int min_white_captured_stones = 0;
int min_black_captured_stones = 0;
int white_suicide = 0;
int black_suicide = 0;
int white_self_atari = 0;
int black_self_atari = 0;
int white_captured_stones = 0;
int black_captured_stones = 0;
int k;
for (k = 0; k < 4; k++) {
int pos2 = pos + delta[k];
switch (mc->board[pos2]) {
case EMPTY:
min_white_liberties++;
min_black_liberties++;
break;
case WHITE:
if (mc_is_in_atari2(mc, pos, (pos << 2) | k)) {
min_black_liberties++;
min_white_captured_stones++;
}
else
white_liberty_through_stones = 1;
break;
case BLACK:
if (mc_is_in_atari2(mc, pos, (pos << 2) | k)) {
min_white_liberties++;
min_black_captured_stones++;
}
else
black_liberty_through_stones = 1;
break;
}
}
if (min_white_liberties + white_liberty_through_stones == 0) {
white_suicide = 1;
white_self_atari = 1;
}
else if (min_white_liberties <= 1)
white_self_atari = mc_is_self_atari(mc, pos, WHITE);
if (min_black_liberties + black_liberty_through_stones == 0) {
black_suicide = 1;
black_self_atari = 1;
}
else if (min_black_liberties <= 1)
black_self_atari = mc_is_self_atari(mc, pos, BLACK);
if (min_white_captured_stones >= 3)
white_captured_stones = 3;
else if (min_white_captured_stones > 0)
white_captured_stones = mc_stones_in_atari(mc, pos, BLACK, 3);
if (min_black_captured_stones >= 3)
black_captured_stones = 3;
else if (min_black_captured_stones > 0)
black_captured_stones = mc_stones_in_atari(mc, pos, WHITE, 3);
mc->local_context[pos] &= 0xffff;
mc->local_context[pos] |= black_captured_stones << 16;
mc->local_context[pos] |= white_captured_stones << 18;
mc->local_context[pos] |= white_self_atari << 20;
mc->local_context[pos] |= black_self_atari << 21;
mc->local_context[pos] |= white_suicide << 22;
mc->local_context[pos] |= black_suicide << 23;
}
/* Play the move at pos by color. */
static int
mc_play_move(struct mc_board *mc, int pos, int color)
{
int k;
int captured_stones = 0;
int num_direct_liberties = 0;
int pos2;
/* Clear the update queue. */
while (mc->queue[0] != 1) {
pos2 = mc->queue[0];
mc->queue[0] = mc->queue[pos2];
mc->queue[pos2] = 0;
}
if (pos == PASS_MOVE) {
if (mc->board_ko_pos != NO_MOVE)
hashdata_invert_ko(&mc->hash, mc->board_ko_pos);
mc->board_ko_pos = NO_MOVE;
return 1;
}
/* The move must not be the ko point. */
if (pos == mc->board_ko_pos) {
if (mc->board[WEST(pos)] == OTHER_COLOR(color)
|| mc->board[EAST(pos)] == OTHER_COLOR(color)) {
return 0;
}
}
/* Test for suicide. */
if (mc_is_suicide(mc, pos, color))
return 0;
if (mc->board_ko_pos != NO_MOVE)
hashdata_invert_ko(&mc->hash, mc->board_ko_pos);
mc->board_ko_pos = NO_MOVE;
#if !TURN_OFF_ASSERTIONS
ASSERT1(mc->board[pos] == EMPTY, pos);
#endif
mc->board[pos] = color;
hashdata_invert_stone(&mc->hash, pos, color);
mc->next_stone[pos] = pos;
/* Update the geometry part of the local context. */
mc->local_context[NW(pos)] |= color << 14;
mc->local_context[SW(pos)] |= color << 12;
mc->local_context[SE(pos)] |= color << 10;
mc->local_context[NE(pos)] |= color << 8;
mc->local_context[WEST(pos)] |= color << 6;
mc->local_context[SOUTH(pos)] |= color << 4;
mc->local_context[EAST(pos)] |= color << 2;
mc->local_context[NORTH(pos)] |= color;
mc->reference_stone[pos] = pos;
mc->first_liberty_edge[pos] = 0;
for (k = 0; k < 4; k++) {
pos2 = pos + delta[k];
if (mc->board[pos2] == EMPTY) {
mc_add_liberty_edge(mc, pos, pos2, (k + 2) % 4);
num_direct_liberties++;
MC_ADD_TO_UPDATE_QUEUE(mc, pos2);
}
}
for (k = 0; k < 4; k++) {
int liberty;
pos2 = pos + delta[k];
if (mc->board[pos2] == color) {
if (mc->reference_stone[pos] != mc->reference_stone[pos2]) {
if (mc_has_two_liberties_one_given(mc, pos2, pos, &liberty))
MC_ADD_TO_UPDATE_QUEUE(mc, liberty);
mc_join_strings(mc, pos, pos2);
}
mc_remove_liberty_edge(mc, pos2, pos, k);
}
}
for (k = 0; k < 4; k++) {
pos2 = pos + delta[k];
if (mc->board[pos2] == OTHER_COLOR(color)) {
if (mc_remove_liberty_edge(mc, pos2, pos, k) == 0)
captured_stones += mc_remove_string(mc, pos2);
else
mc_queue_max_two_liberties(mc, pos2);
}
}
if (captured_stones == 1
&& mc->next_stone[pos] == pos
&& num_direct_liberties == 0) {
mc->board_ko_pos = mc->first_liberty_edge[pos] >> 2;
hashdata_invert_ko(&mc->hash, mc->board_ko_pos);
}
mc_queue_max_two_liberties(mc, pos);
/* Traverse the update queue and update the local context for queued
* points.
*/
for (pos2 = mc->queue[0]; pos2 != 1; pos2 = mc->queue[pos2])
if (pos2 != pos)
mc_update_local_context(mc, pos2);
/* Add the immediate neighborhood of the move to the update queue
* for recomputation of move values later on.
*/
MC_ADD_TO_UPDATE_QUEUE(mc, pos);
for (k = 0; k < 8; k++)
if (mc->board[pos + delta[k]] == EMPTY)
MC_ADD_TO_UPDATE_QUEUE(mc, pos + delta[k]);
return 1;
}
/***************************************************/
#define NUM_GEOMETRIES 1107
#define NUM_PROPERTIES 256
struct mc_pattern_table
{
unsigned short geometry_table[65536];
unsigned int values[(NUM_GEOMETRIES + 1) * NUM_PROPERTIES];
};
static struct mc_pattern_table mc_patterns;
/* The pattern number is determined by the following bit layout:
* 18-8: Geometry number (range 1..1107)
* 7 : Opponent suicide
* 6 : Our self-atari
* 5 : Opponent self-atari
* 4,3 : Our captures
* 2,1 : Opponent captures
* 0 : Near
*/
static int
mc_find_pattern_number(struct mc_board *mc, int move, int color,
int near_previous_move)
{
int local_context = mc->local_context[move];
int properties;
int geometry;
if (color == WHITE) {
properties = (((local_context >> 16) & 0xa0)
| ((local_context >> 14) & 0x40)
| ((local_context >> 17) & 0x06)
| ((local_context >> 13) & 0x18));
geometry = local_context & 0xffff;
}
else {
properties = (local_context >> 15) & 0xfe;
geometry = (((local_context & 0x5555) << 1)
| ((local_context & 0xaaaa) >> 1));
}
return ((mc_patterns.geometry_table[geometry] << 8)
| properties
| near_previous_move);
}
/* Geometry patterns have the neighborhood defined by the order
*
* 637
* 2*4
* 518
*
* where * is the point to play. The reason for this seemingly
* arbitrary order is to be consistent with the delta[] array
* of point offsets.
*
* The 8 rotation/mirror transformations are given by reordering the
* points like this:
* 12345678 no transform
* 41238567 rotation 90
* 34127856 rotation 180
* 23416785 rotation 270
* 14328765 mirror
* 21435876 mirror + rotation 90
* 32146587 mirror + rotation 180
* 43217658 mirror + rotation 270
*
* The geometry is encoded by a 16-bit integer where point 1 goes into
* the 2 least significant bits and point 8 into the 2 most
* significant bits. Each pair of bits contain the corresponding
* EMPTY, WHITE, BLACK, GRAY (off board) values.
*/
static unsigned short
mc_register_geometry_pattern(unsigned int pattern, unsigned short n)
{
int k;
int j;
unsigned int transformed_pattern;
if (mc_patterns.geometry_table[pattern] != 0)
return 0;
for (k = 0; k < 8; k++) {
transformed_pattern = pattern;
if (k >= 4) {
/* Mirror pattern. */
transformed_pattern = (((pattern & 0x0300) << 6)
| ((pattern & 0x000c) << 4)
| ((pattern & 0x0c00) << 2)
| (pattern & 0x0033)
| ((pattern & 0x3000) >> 2)
| ((pattern & 0x00c0) >> 4)
| ((pattern & 0xc000) >> 6));
}
/* Rotate pattern. */
for (j = 0; j < k % 4; j++) {
transformed_pattern = (((transformed_pattern & 0xc0c0) >> 6)
| ((transformed_pattern & 0x3f3f) << 2));
}
mc_patterns.geometry_table[transformed_pattern] = n;
}
return 1;
}
/* Compute the mapping from 8-point local neighborhoods to rotation
* invariant geometry numbers.
*/
static void
mc_init_pattern_geometries(void)
{
unsigned int pattern;
unsigned short n = 1;
static int initialized = 0;
if (initialized)
return;
initialized = 1;
memset(mc_patterns.geometry_table, 0, sizeof(mc_patterns.geometry_table));
for (pattern = 0; pattern < 65536; pattern++) {
unsigned int off_board = (pattern & (pattern >> 1)) & 0x5555;
if (off_board == 0x0 || off_board == 0x1410 || off_board == 0x5450)
n += mc_register_geometry_pattern(pattern, n);
}
gg_assert(n == NUM_GEOMETRIES + 1);
}
/* Determine which geometry numbers are matched by a pattern with
* possible wildcards, for use when loading pattern databases.
*
* This function is recursive with the argument n determining which
* point in the neighborhood is expanded for wildcards.
*/
static void
mc_match_geometries(int pattern[8], int *matching_geometries, int n)
{
int k;
int geometry = 0;
if (n == 8) {
/* The pattern has been fully expanded. Find the geometry number. */
for (k = 0; k < 8; k++) {
if (pattern[k] == 'O')
geometry |= WHITE << (2 * k);
else if (pattern[k] == 'X')
geometry |= BLACK << (2 * k);
else if (pattern[k] == '+' || pattern[k] == '|' || pattern[k] == '-')
geometry |= (WHITE | BLACK) << (2 * k);
}
if (mc_patterns.geometry_table[geometry] != 0) {
matching_geometries[mc_patterns.geometry_table[geometry]] = 1;
}
}
else {
/* Recurse with all possible expansions of the current
* neighborhood point.
*/
int new_pattern[8];
memcpy(new_pattern, pattern, sizeof(new_pattern));
switch (pattern[n]) {
case '.':
case 'O':
case 'X':
case '|':
case '-':
case '+':
mc_match_geometries(new_pattern, matching_geometries, n + 1);
break;
case 'o':
new_pattern[n] = '.';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'O';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
break;
case 'x':
new_pattern[n] = '.';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'X';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
break;
case '?':
new_pattern[n] = '.';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'O';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'X';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
break;
case '%':
new_pattern[n] = '.';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'O';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = 'X';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
new_pattern[n] = '+';
mc_match_geometries(new_pattern, matching_geometries, n + 1);
break;
}
}
}
/* Clear a subset of the property combinations determined by shift,
* mask, and value.
*/
static void
mc_clear_properties(int *properties, int shift, int mask, int value)
{
int k;
for (k = 0; k < NUM_PROPERTIES; k++)
if (((k >> shift) & mask) == value)
properties[k] = 0;
}
/* Find which property combinations are consistent with the rules
* given in buf.
*/
static void
mc_analyze_properties(char *buf, int *properties)
{
int k;
/* First set all properties. */
for (k = 0; k < NUM_PROPERTIES; k++)
properties[k] = 1;
/* Then reset the ones which are inconsistent. */
if (strstr(buf, "near"))
mc_clear_properties(properties, 0, 1, 0);
if (strstr(buf, "far"))
mc_clear_properties(properties, 0, 1, 1);
if (strstr(buf, "xcap0")) {
mc_clear_properties(properties, 1, 3, 1);
mc_clear_properties(properties, 1, 3, 2);
mc_clear_properties(properties, 1, 3, 3);
}
if (strstr(buf, "xcap1+"))
mc_clear_properties(properties, 1, 3, 0);
else if (strstr(buf, "xcap1-")) {
mc_clear_properties(properties, 1, 3, 2);
mc_clear_properties(properties, 1, 3, 3);
}
else if (strstr(buf, "xcap1")) {
mc_clear_properties(properties, 1, 3, 0);
mc_clear_properties(properties, 1, 3, 2);
mc_clear_properties(properties, 1, 3, 3);
}
if (strstr(buf, "xcap2+")) {
mc_clear_properties(properties, 1, 3, 0);
mc_clear_properties(properties, 1, 3, 1);
}
else if (strstr(buf, "xcap2-"))
mc_clear_properties(properties, 1, 3, 3);
else if (strstr(buf, "xcap2")) {
mc_clear_properties(properties, 1, 3, 0);
mc_clear_properties(properties, 1, 3, 1);
mc_clear_properties(properties, 1, 3, 3);
}
if (strstr(buf, "xcap3")) {
mc_clear_properties(properties, 1, 3, 0);
mc_clear_properties(properties, 1, 3, 1);
mc_clear_properties(properties, 1, 3, 2);
}
if (strstr(buf, "ocap0")) {
mc_clear_properties(properties, 3, 3, 1);
mc_clear_properties(properties, 3, 3, 2);
mc_clear_properties(properties, 3, 3, 3);
}
if (strstr(buf, "ocap1+"))
mc_clear_properties(properties, 3, 3, 0);
else if (strstr(buf, "ocap1-")) {
mc_clear_properties(properties, 3, 3, 2);
mc_clear_properties(properties, 3, 3, 3);
}
else if (strstr(buf, "ocap1")) {
mc_clear_properties(properties, 3, 3, 0);
mc_clear_properties(properties, 3, 3, 2);
mc_clear_properties(properties, 3, 3, 3);
}
if (strstr(buf, "ocap2+")) {
mc_clear_properties(properties, 3, 3, 0);
mc_clear_properties(properties, 3, 3, 1);
}
else if (strstr(buf, "ocap2-"))
mc_clear_properties(properties, 3, 3, 3);
else if (strstr(buf, "ocap2")) {
mc_clear_properties(properties, 3, 3, 0);
mc_clear_properties(properties, 3, 3, 1);
mc_clear_properties(properties, 3, 3, 3);
}
if (strstr(buf, "ocap3")) {
mc_clear_properties(properties, 3, 3, 0);
mc_clear_properties(properties, 3, 3, 1);
mc_clear_properties(properties, 3, 3, 2);
}
if (strstr(buf, "xsafe"))
mc_clear_properties(properties, 5, 1, 1);
if (strstr(buf, "xunsafe"))
mc_clear_properties(properties, 5, 1, 0);
if (strstr(buf, "osafe"))
mc_clear_properties(properties, 6, 1, 1);
if (strstr(buf, "ounsafe"))
mc_clear_properties(properties, 6, 1, 0);
if (strstr(buf, "xsuicide"))
mc_clear_properties(properties, 7, 1, 0);
if (strstr(buf, "xnosuicide"))
mc_clear_properties(properties, 7, 1, 1);
}
/* Export the size of the array mc_patterns.values so that external
* callers of mc_load_patterns_from_db() know how big arrays to
* allocate.
*/
int
mc_get_size_of_pattern_values_table(void)
{
return (NUM_GEOMETRIES + 1) * NUM_PROPERTIES;
}
/* Load Monte Carlo patterns from file in .db format. If values is
* NULL, load directly into mc_patterns.values.
*/
int
mc_load_patterns_from_db(const char *filename, unsigned int *values)
{
FILE *pattern_file;
char buf[80];
unsigned int value;
int pattern_line = 0;
int current_pattern[8];
int patterns_expanded = 0;
int *matching_geometries;
int properties[NUM_PROPERTIES];
int k;
int m;
if (!values)
values = mc_patterns.values;
mc_init_pattern_geometries();
pattern_file = fopen(filename, "r");
if (!pattern_file) {
gprintf("Failed to open %s file.\n", filename);
return 0;
}
matching_geometries = malloc((NUM_GEOMETRIES + 1)
* sizeof(*matching_geometries));
/* Set unloaded patterns to a "-1" value. */
for (k = 1; k <= NUM_GEOMETRIES; k++)
for (m = 0; m < NUM_PROPERTIES; m++)
values[k * NUM_PROPERTIES + m] = 0xffffffffU;
/* Loop over the rows of the pattern database. */
while (fgets(buf, 80, pattern_file)) {
if (strchr(".xXoO|+-?%", buf[0])) {
/* Pattern line found */
patterns_expanded = 0;
if (pattern_line == 0) {
current_pattern[5] = buf[0];
current_pattern[2] = buf[1];
current_pattern[6] = buf[2];
}
else if (pattern_line == 1) {
current_pattern[1] = buf[0];
current_pattern[3] = buf[2];
}
else if (pattern_line == 2) {
current_pattern[4] = buf[0];
current_pattern[0] = buf[1];
current_pattern[7] = buf[2];
}
pattern_line++;
}
else if (sscanf(buf, ":%u", &value) == 1) {
/* Colon line found. */
if (value > 10000000)
fprintf(stderr, "Warning: pattern values should be at most 10000000.");
if (!patterns_expanded) {
/* Find the set of rotation invariant geometries matching the
* pattern.
*/
memset(matching_geometries, 0,
(NUM_GEOMETRIES + 1) * sizeof(*matching_geometries));
mc_match_geometries(current_pattern, matching_geometries, 0);
patterns_expanded = 1;
}
/* Find the set of matching property values. */
mc_analyze_properties(buf, properties);
/* Set the value for the combinations of matched geometries and
* properties, except those which have already been matched by a
* previous pattern.
*/
for (k = 1; k <= NUM_GEOMETRIES; k++)
if (matching_geometries[k])
for (m = 0; m < NUM_PROPERTIES; m++)
if (properties[m] && values[k * NUM_PROPERTIES + m] == 0xffffffffU)
values[k * NUM_PROPERTIES + m] = value;
pattern_line = 0;
}
}
fclose(pattern_file);
/* Set unmatched patterns/properties to a value of 1. */
for (k = 1; k <= NUM_GEOMETRIES; k++)
for (m = 0; m < NUM_PROPERTIES; m++)
if (values[k * NUM_PROPERTIES + m] == 0xffffffffU)
values[k * NUM_PROPERTIES + m] = 1;
free(matching_geometries);
return 1;
}
/* Set up local pattern values. */
void
mc_init_patterns(const unsigned int *values)
{
mc_init_pattern_geometries();
memcpy(mc_patterns.values, values, sizeof(mc_patterns.values));
}
/* Initialize the data structures used to keep track of the local
* pattern values.
*/
static void
mc_init_move_values(struct mc_board *mc)
{
int pos;
int k;
memset(mc->move_values_white, 0, sizeof(mc->move_values_white));
memset(mc->move_values_black, 0, sizeof(mc->move_values_black));
memset(mc->partitioned_move_value_sums_white, 0,
sizeof(mc->partitioned_move_value_sums_white));
memset(mc->partitioned_move_value_sums_black, 0,
sizeof(mc->partitioned_move_value_sums_black));
memset(mc->move_partition_lists_white, 0,
sizeof(mc->move_partition_lists_white));
memset(mc->move_partition_lists_black, 0,
sizeof(mc->move_partition_lists_black));
mc->move_value_sum_white = 0.0;
mc->move_value_sum_black = 0.0;
for (k = 0; k < NUM_MOVE_PARTITIONS; k++) {
mc->move_partition_lists_white[k] = 1;
mc->move_partition_lists_black[k] = 1;
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (mc->board[pos] == EMPTY) {
int partition = pos & (NUM_MOVE_PARTITIONS - 1);
if (!mc_is_suicide(mc, pos, WHITE)) {
int pattern = mc_find_pattern_number(mc, pos, WHITE, 0);
unsigned int value = mc_patterns.values[pattern];
mc->move_values_white[pos] = value;
mc->partitioned_move_value_sums_white[partition] += value;
mc->move_value_sum_white += value;
mc->move_partition_lists_white[pos] = mc->move_partition_lists_white[partition];
mc->move_partition_lists_white[partition] = pos;
}
if (!mc_is_suicide(mc, pos, BLACK)) {
int pattern = mc_find_pattern_number(mc, pos, BLACK, 0);
unsigned int value = mc_patterns.values[pattern];
mc->move_values_black[pos] = value;
mc->partitioned_move_value_sums_black[partition] += value;
mc->move_value_sum_black += value;
mc->move_partition_lists_black[pos] = mc->move_partition_lists_black[partition];
mc->move_partition_lists_black[partition] = pos;
}
}
}
}
/* Add a move at a vertex which was previously not a legal move. */
static void
mc_add_move(struct mc_board *mc, int pos, int color, int partition,
unsigned int *move_values, int *partition_lists,
unsigned int *partition_sums, unsigned int *move_value_sum)
{
int pattern = mc_find_pattern_number(mc, pos, color, 0);
unsigned int value = mc_patterns.values[pattern];
partition_lists[pos] = partition_lists[partition];
partition_lists[partition] = pos;
move_values[pos] = value;
partition_sums[partition] += value;
*move_value_sum += value;
}
/* Update a move value. */
static void
mc_update_move(struct mc_board *mc, int pos, int color, int partition,
unsigned int *move_values, unsigned int *partition_sums,
unsigned int *move_value_sum)
{
int pattern = mc_find_pattern_number(mc, pos, color, 0);
unsigned int value = mc_patterns.values[pattern];
partition_sums[partition] += value - move_values[pos];
*move_value_sum += value - move_values[pos];
move_values[pos] = value;
}
/* Remove a move because it has been played or has become suicide. */
static void
mc_remove_move(int pos, int partition, unsigned int *move_values,
int *partition_lists, unsigned int *partition_sums,
unsigned int *move_value_sum)
{
int pos2;
int pos3;
for (pos2 = partition; partition_lists[pos2] != 1; pos2 = partition_lists[pos2]) {
if (partition_lists[pos2] == pos)
break;
}
pos3 = partition_lists[pos2];
partition_lists[pos2] = partition_lists[pos3];
partition_lists[pos3] = 0;
partition_sums[partition] -= move_values[pos];
*move_value_sum -= move_values[pos];
move_values[pos] = 0.0;
}
/* Update move values for the moves listed in the update queue. */
static void
mc_update_move_values(struct mc_board *mc)
{
int pos;
int partition;
for (pos = mc->queue[0]; pos != 1; pos = mc->queue[pos]) {
partition = pos & (NUM_MOVE_PARTITIONS - 1);
if ((mc->board[pos] != EMPTY || mc_is_suicide(mc, pos, WHITE))) {
if (mc->move_partition_lists_white[pos] != 0) {
mc_remove_move(pos, partition, mc->move_values_white,
mc->move_partition_lists_white,
mc->partitioned_move_value_sums_white,
&mc->move_value_sum_white);
}
}
else {
if (mc->move_partition_lists_white[pos] == 0)
mc_add_move(mc, pos, WHITE, partition, mc->move_values_white,
mc->move_partition_lists_white,
mc->partitioned_move_value_sums_white,
&mc->move_value_sum_white);
else
mc_update_move(mc, pos, WHITE, partition, mc->move_values_white,
mc->partitioned_move_value_sums_white,
&mc->move_value_sum_white);
}
if ((mc->board[pos] != EMPTY || mc_is_suicide(mc, pos, BLACK))) {
if (mc->move_partition_lists_black[pos] != 0) {
mc_remove_move(pos, partition, mc->move_values_black,
mc->move_partition_lists_black,
mc->partitioned_move_value_sums_black,
&mc->move_value_sum_black);
}
}
else {
if (mc->move_partition_lists_black[pos] == 0)
mc_add_move(mc, pos, BLACK, partition, mc->move_values_black,
mc->move_partition_lists_black,
mc->partitioned_move_value_sums_black,
&mc->move_value_sum_black);
else
mc_update_move(mc, pos, BLACK, partition, mc->move_values_black,
mc->partitioned_move_value_sums_black,
&mc->move_value_sum_black);
}
}
}
/***************************************************/
#define ASSERT_LEGAL 1
struct mc_game {
struct mc_board mc;
int move_history[600];
unsigned char settled[BOARDMAX];
int color_to_move;
int last_move;
int consecutive_passes;
int consecutive_ko_captures;
int depth;
};
/* Generate a random move. */
static int
mc_generate_random_move(struct mc_game *game)
{
struct mc_board *mc = &game->mc;
int last_move = game->last_move;
int color = game->color_to_move;
int depth = game->depth;
int pos;
int near_moves[BOARDMAX];
unsigned int saved_near_move_values[BOARDMAX];
int num_near_moves;
unsigned int *move_values;
unsigned int *partition_sums;
int *partition_lists;
unsigned int *move_value_sum;
unsigned int saved_ko_value = 0;
int partition;
int move;
int k;
int x;
/* If we get this deep we are almost certainly playing triple ko
* without alternative options, so just give up and score as is.
*
* FIXME: Handle this in some proper way.
*/
if (depth > 600) {
if (mc_debug) {
int pos;
fprintf(stderr, "Reached 600 iterations.\n");
mc_showboard(mc, stderr);
for (k = 0; k < game->depth; k++)
gprintf("%1m ", game->move_history[k]);
gprintf("\n");
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (mc->board[pos] == EMPTY) {
gprintf("%1m ", pos);
fprintf(stderr, "white %7d black %7d white near %7d black near %7d\n",
(int) mc->move_values_white[pos],
(int) mc->move_values_black[pos],
mc_patterns.values[mc_find_pattern_number(mc, pos, WHITE, 1)],
mc_patterns.values[mc_find_pattern_number(mc, pos, BLACK, 1)]);
}
}
return PASS_MOVE;
}
if (color == WHITE) {
move_values = mc->move_values_white;
partition_sums = mc->partitioned_move_value_sums_white;
partition_lists = mc->move_partition_lists_white;
move_value_sum = &mc->move_value_sum_white;
}
else {
move_values = mc->move_values_black;
partition_sums = mc->partitioned_move_value_sums_black;
partition_lists = mc->move_partition_lists_black;
move_value_sum = &mc->move_value_sum_black;
}
/* Temporarily update pattern values for NEAR moves. We define
* NEAR moves as those which had their values updated during the
* previous mc_play_move() call and can be found by traversing the
* update queue.
*/
num_near_moves = 0;
if (last_move != PASS_MOVE) {
for (pos = mc->queue[0]; pos != 1; pos = mc->queue[pos]) {
if (mc->board[pos] == EMPTY && partition_lists[pos] != 0) {
unsigned int old_value = move_values[pos];
int pattern = mc_find_pattern_number(mc, pos, color, 1);
unsigned int new_value = mc_patterns.values[pattern];
partition = pos & (NUM_MOVE_PARTITIONS - 1);
saved_near_move_values[num_near_moves] = old_value;
near_moves[num_near_moves++] = pos;
move_values[pos] = new_value;
partition_sums[partition] += new_value - old_value;
*move_value_sum += new_value - old_value;
}
}
}
/* Temporarily clear the move value of an illegal ko capture. */
if (mc->board_ko_pos != NO_MOVE) {
if (mc->board[WEST(mc->board_ko_pos)] == OTHER_COLOR(color)
|| mc->board[EAST(mc->board_ko_pos)] == OTHER_COLOR(color)) {
partition = mc->board_ko_pos & (NUM_MOVE_PARTITIONS - 1);
saved_ko_value = move_values[mc->board_ko_pos];
move_values[mc->board_ko_pos] = 0;
partition_sums[partition] -= saved_ko_value;
*move_value_sum -= saved_ko_value;
}
}
/* Sample a move randomly according to the distribution given by
* the move values.
*/
if (*move_value_sum == 0)
move = PASS_MOVE;
else {
/* First choose a partition. */
x = (int) (gg_drand() * *move_value_sum);
for (k = 0; k < NUM_MOVE_PARTITIONS; k++) {
x -= partition_sums[k];
if (x < 0)
break;
}
/* Then choose a move in that partition. */
x = (unsigned int) (gg_drand() * partition_sums[k]);
for (pos = partition_lists[k]; pos != 1; pos = partition_lists[pos]) {
x -= move_values[pos];
if (x < 0)
break;
}
move = pos;
#if !TURN_OFF_ASSERTIONS
ASSERT1(move == PASS_MOVE || move_values[move] > 0, move);
ASSERT1(move == PASS_MOVE || mc->board[move] == EMPTY, move);
ASSERT1(mc_is_legal(mc, move, color), move);
#endif
}
/* Reset the value of an illegal ko capture. */
if (saved_ko_value > 0) {
partition = mc->board_ko_pos & (NUM_MOVE_PARTITIONS - 1);
partition_sums[partition] += saved_ko_value - move_values[mc->board_ko_pos];
*move_value_sum += saved_ko_value - move_values[mc->board_ko_pos];
move_values[mc->board_ko_pos] = saved_ko_value;
}
/* Reset move values for NEAR moves. */
for (k = 0; k < num_near_moves; k++) {
unsigned int old_value;
unsigned int new_value;
pos = near_moves[k];
partition = pos & (NUM_MOVE_PARTITIONS - 1);
old_value = move_values[pos];
new_value = saved_near_move_values[k];
move_values[pos] = new_value;
partition_sums[partition] += new_value - old_value;
*move_value_sum += new_value - old_value;
}
return move;
}
static int mc_play_random_move(struct mc_game *game, int move)
{
int result = mc_play_move(&game->mc, move, game->color_to_move);
mc_update_move_values(&game->mc);
if (result) {
if (is_pass(move))
game->consecutive_passes++;
else {
game->consecutive_passes = 0;
}
if (game->mc.board_ko_pos != NO_MOVE)
game->consecutive_ko_captures++;
else
game->consecutive_ko_captures = 0;
game->move_history[game->depth] = move;
game->last_move = move;
game->color_to_move = OTHER_COLOR(game->color_to_move);
game->depth++;
}
return result;
}
static int mc_play_random_game(struct mc_game *game)
{
struct mc_board *mc = &game->mc;
int score = 0;
int pos;
int k;
int result;
int move;
/* First finish the game, if it isn't already. */
while (game->consecutive_passes < 3) {
move = mc_generate_random_move(game);
result = mc_play_random_move(game, move);
ASSERT1(result, move);
}
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (MC_ON_BOARD(pos)) {
if (game->settled[pos] == WHITE)
score++;
else if (game->settled[pos] == BLACK)
score--;
else {
int pos2 = pos;
if (mc->board[pos] == EMPTY)
for (k = 0; k < 4; k++) {
pos2 = pos + delta[k];
if (IS_STONE(mc->board[pos2]))
break;
}
score += 2 * (mc->board[pos2] == WHITE) - 1;
}
}
return score;
}
/******************* UCT search ***********************/
#define UCT_MAX_SEARCH_DEPTH BOARDMAX
struct bitboard {
/* FIXME: Do this properly. */
unsigned int bits[1 + BOARDMAX / 32];
};
struct uct_arc {
int move;
struct uct_node *node;
struct uct_arc *next;
};
struct uct_node {
int wins;
int games;
float sum_scores;
float sum_scores2;
struct uct_arc *child;
struct bitboard untested;
Hash_data boardhash;
};
struct uct_tree {
struct uct_node *nodes;
struct uct_arc *arcs;
unsigned int *hashtable_odd;
unsigned int *hashtable_even;
unsigned int hashtable_size;
int num_nodes;
int num_used_nodes;
int num_arcs;
int num_used_arcs;
int *forbidden_moves;
struct mc_game game;
int move_score[BOARDSIZE];
int move_ordering[BOARDSIZE];
int inverse_move_ordering[BOARDSIZE];
int num_ordered_moves;
};
static struct uct_node *
uct_init_node(struct uct_tree *tree, int *allowed_moves)
{
int pos;
struct uct_node *node = &tree->nodes[tree->num_used_nodes++];
node->wins = 0;
node->games = 0;
node->sum_scores = 0.0;
node->sum_scores2 = 0.0;
node->child = NULL;
memset(node->untested.bits, 0, sizeof(node->untested.bits));
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (tree->game.mc.board[pos] == EMPTY
&& !tree->forbidden_moves[pos]
&& (!allowed_moves || allowed_moves[pos])) {
node->untested.bits[pos / 32] |= 1 << pos % 32;
}
}
node->boardhash = tree->game.mc.hash;
return node;
}
static struct uct_node *
uct_find_node(struct uct_tree *tree, struct uct_node *parent, int move)
{
struct uct_node *node = NULL;
Hash_data *boardhash = &tree->game.mc.hash;
unsigned int hash_index = hashdata_remainder(*boardhash,
tree->hashtable_size);
unsigned int *hashtable = tree->hashtable_even;
if (tree->game.depth & 1)
hashtable = tree->hashtable_odd;
while (hashtable[hash_index] != 0) {
int node_index = hashtable[hash_index];
gg_assert(node_index > 0 && node_index < tree->num_nodes);
if (hashdata_is_equal(tree->nodes[node_index].boardhash, *boardhash)) {
node = &tree->nodes[node_index];
break;
}
hash_index++;
if (hash_index >= tree->hashtable_size)
hash_index = 0;
}
if (!node) {
node = uct_init_node(tree, NULL);
gg_assert(hash_index < tree->hashtable_size);
hashtable[hash_index] = node - tree->nodes;
}
/* Add the node as the first of the siblings. */
if (parent) {
struct uct_arc *arc = &tree->arcs[tree->num_used_arcs++];
gg_assert(tree->num_used_arcs < tree->num_arcs);
arc->move = move;
arc->node = node;
if (parent->child)
arc->next = parent->child;
else
arc->next = NULL;
parent->child = arc;
}
return node;
}
static void
uct_update_move_ordering(struct uct_tree *tree, int move)
{
int score = ++tree->move_score[move];
while (1) {
int n = tree->inverse_move_ordering[move];
int preceding_move;
if (n == 0)
return;
preceding_move = tree->move_ordering[n - 1];
if (tree->move_score[preceding_move] >= score)
return;
/* Swap move ordering. */
tree->move_ordering[n - 1] = move;
tree->move_ordering[n] = preceding_move;
tree->inverse_move_ordering[move] = n - 1;
tree->inverse_move_ordering[preceding_move] = n;
}
}
static void
uct_init_move_ordering(struct uct_tree *tree)
{
int pos;
int k = 0;
/* FIXME: Exclude forbidden moves. */
memset(tree->move_score, 0, sizeof(tree->move_score));
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
if (ON_BOARD(pos)) {
tree->move_ordering[k] = pos;
tree->inverse_move_ordering[pos] = k;
k++;
}
tree->num_ordered_moves = k;
/* FIXME: Quick and dirty experiment. */
for (pos = BOARDMIN; pos < BOARDMAX; pos++) {
if (ON_BOARD(pos)) {
tree->move_score[pos] = (int) (10 * potential_moves[pos]) - 1;
uct_update_move_ordering(tree, pos);
}
}
}
static float
uct_finish_and_score_game(struct mc_game *game)
{
return komi + mc_play_random_game(game);
}
static struct uct_node *
uct_play_move(struct uct_tree *tree, struct uct_node *node, float alpha,
float *gamma, int *move)
{
struct uct_arc *child_arc;
int pos;
struct uct_arc *next_arc = NULL;
struct uct_arc *best_winrate_arc = NULL;
float best_uct_value = 0.0;
float best_winrate = 0.0;
for (child_arc = node->child; child_arc; child_arc = child_arc->next) {
struct uct_node *child_node = child_arc->node;
float winrate = (float) child_node->wins / child_node->games;
float uct_value;
float log_games_ratio = log(node->games) / child_node->games;
float x = winrate * (1.0 - winrate) + sqrt(2.0 * log_games_ratio);
if (x < 0.25)
x = 0.25;
uct_value = winrate + sqrt(2 * log_games_ratio * x / (1 + tree->game.depth));
if (uct_value > best_uct_value) {
next_arc = child_arc;
best_uct_value = uct_value;
}
if (winrate > best_winrate) {
best_winrate_arc = child_arc;
best_winrate = winrate;
}
}
*gamma = best_winrate;
if (best_winrate > alpha)
next_arc = best_winrate_arc;
else {
/* First play a random previously unplayed move, if any. */
int k;
for (k = -1; k < tree->num_ordered_moves; k++) {
if (k == -1 && best_uct_value > 0.0)
continue;
else if (k == -1)
pos = mc_generate_random_move(&tree->game);
else
pos = tree->move_ordering[k];
if (node->untested.bits[pos / 32] & (1 << (pos % 32))) {
int r;
int proper_small_eye = 1;
struct mc_board *mc = &tree->game.mc;
*move = pos;
node->untested.bits[*move / 32] &= ~(1 << *move % 32);
for (r = 0; r < 4; r++) {
if (mc->board[pos + delta[r]] == EMPTY
|| mc->board[pos + delta[r]] == OTHER_COLOR(tree->game.color_to_move)) {
proper_small_eye = 0;
break;
}
}
if (proper_small_eye) {
int diagonal_value = 0;
for (r = 4; r < 8; r++) {
int pos2 = pos + delta[r];
if (!MC_ON_BOARD(pos2))
diagonal_value++;
else if (mc->board[pos2] == OTHER_COLOR(tree->game.color_to_move))
diagonal_value += 2;
}
if (diagonal_value > 3)
proper_small_eye = 0;
}
if (!proper_small_eye && mc_play_random_move(&tree->game, *move))
return uct_find_node(tree, node, *move);
}
}
}
if (!next_arc) {
mc_play_random_move(&tree->game, PASS_MOVE);
*move = PASS_MOVE;
return uct_find_node(tree, node, PASS_MOVE);
}
*move = next_arc->move;
mc_play_random_move(&tree->game, next_arc->move);
return next_arc->node;
}
static float
uct_traverse_tree(struct uct_tree *tree, struct uct_node *node,
float alpha, float beta)
{
int color = tree->game.color_to_move;
int num_passes = tree->game.consecutive_passes;
float result;
float gamma;
int move = PASS_MOVE;
/* FIXME: Unify these. */
if (num_passes == 3 || tree->game.depth >= UCT_MAX_SEARCH_DEPTH
|| (node->games == 0 && node != tree->nodes))
result = uct_finish_and_score_game(&tree->game);
else {
struct uct_node *next_node;
next_node = uct_play_move(tree, node, alpha, &gamma, &move);
gamma += 0.00;
if (gamma > 0.8)
gamma = 0.8;
result = uct_traverse_tree(tree, next_node, beta, gamma);
}
node->games++;
if ((result > 0) ^ (color == WHITE)) {
node->wins++;
if (move != PASS_MOVE)
uct_update_move_ordering(tree, move);
}
node->sum_scores += result;
node->sum_scores2 += result * result;
return result;
}
static int
uct_find_best_children(struct uct_node *node, struct uct_arc **children,
int n)
{
struct uct_arc *child_arc;
float best_score;
struct uct_arc *best_child;
int found_moves[BOARDMAX];
int k;
memset(found_moves, 0, sizeof(found_moves));
for (k = 0; k < n; k++) {
best_score = 0.0;
best_child = NULL;
for (child_arc = node->child; child_arc; child_arc = child_arc->next) {
struct uct_node *child_node = child_arc->node;
if (!found_moves[child_arc->move]
&& best_score * child_node->games < child_node->wins) {
best_child = child_arc;
best_score = (float) child_node->wins / child_node->games;
}
}
if (!best_child)
break;
children[k] = best_child;
found_moves[best_child->move] = 1;
}
return k;
}
static void
uct_dump_tree_recursive(struct uct_node *node, SGFTree *sgf_tree, int color,
int cutoff, int depth)
{
struct uct_arc *child_arc;
char buf[100];
if (depth > 50)
return;
for (child_arc = node->child; child_arc; child_arc = child_arc->next) {
struct uct_node *child_node = child_arc->node;
sgftreeAddPlayLast(sgf_tree, color,
I(child_arc->move), J(child_arc->move));
gg_snprintf(buf, 100, "%d/%d (%5.3f)", child_node->wins, child_node->games,
(float) child_node->wins / child_node->games);
sgftreeAddComment(sgf_tree, buf);
if (child_node->games >= cutoff)
uct_dump_tree_recursive(child_node, sgf_tree, OTHER_COLOR(color), cutoff, depth + 1);
sgf_tree->lastnode = sgf_tree->lastnode->parent;
}
}
static void
uct_dump_tree(struct uct_tree *tree, const char *filename, int color,
int cutoff)
{
SGFTree sgf_tree;
sgftree_clear(&sgf_tree);
sgftreeCreateHeaderNode(&sgf_tree, board_size, komi, 0);
sgffile_printboard(&sgf_tree);
uct_dump_tree_recursive(&tree->nodes[0], &sgf_tree, color, cutoff, 0);
writesgf(sgf_tree.root, filename);
sgfFreeNode(sgf_tree.root);
}
void
uct_genmove(int color, int *move, int *forbidden_moves, int *allowed_moves,
int nodes, float *move_values, int *move_frequencies)
{
struct uct_tree tree;
float best_score;
struct uct_arc *arc;
struct uct_node *node;
struct mc_game starting_position;
int most_games;
struct uct_node *most_games_node;
struct uct_arc *most_games_arc;
int pos;
mc_init_board_from_global_board(&starting_position.mc);
mc_init_move_values(&starting_position.mc);
starting_position.color_to_move = color;
/* FIXME: Fill in correct information. */
starting_position.consecutive_passes = 0;
starting_position.consecutive_ko_captures = 0;
starting_position.last_move = get_last_move();
starting_position.depth = 0;
for (pos = BOARDMIN; pos < BOARDMAX; pos++)
starting_position.settled[pos] = forbidden_moves[pos];
tree.game = starting_position;
/* FIXME: Don't reallocate between moves. */
tree.nodes = malloc(nodes * sizeof(*tree.nodes));
gg_assert(tree.nodes);
tree.arcs = malloc(nodes * sizeof(*tree.arcs));
gg_assert(tree.arcs);
tree.hashtable_size = nodes;
tree.hashtable_odd = calloc(tree.hashtable_size,
sizeof(*tree.hashtable_odd));
tree.hashtable_even = calloc(tree.hashtable_size,
sizeof(*tree.hashtable_even));
gg_assert(tree.hashtable_odd);
gg_assert(tree.hashtable_even);
tree.num_nodes = nodes;
tree.num_arcs = nodes;
tree.num_used_nodes = 0;
tree.num_used_arcs = 0;
tree.forbidden_moves = forbidden_moves;
uct_init_node(&tree, allowed_moves);
uct_init_move_ordering(&tree);
/* Play simulations. FIXME: Terribly dirty fix. */
while (tree.num_used_arcs < tree.num_arcs - 10) {
int last_used_arcs = tree.num_used_arcs;
tree.game = starting_position;
uct_traverse_tree(&tree, &tree.nodes[0], 1.0, 0.9);
/* FIXME: Ugly workaround for solved positions before running out
* of nodes.
*/
if (tree.num_used_arcs == last_used_arcs)
break;
}
/* Identify the best move on the top level. */
best_score = 0.0;
*move = PASS_MOVE;
for (arc = tree.nodes[0].child; arc; arc = arc->next) {
node = arc->node;
move_frequencies[arc->move] = node->games;
move_values[arc->move] = (float) node->wins / node->games;
if (best_score * node->games < node->wins) {
*move = arc->move;
best_score = (float) node->wins / node->games;
}
}
/* Dump sgf tree of the significant part of the search tree. */
if (0)
uct_dump_tree(&tree, "/tmp/ucttree.sgf", color, 50);
/* Print information about the search tree. */
if (mc_debug) {
while (1) {
float mean;
float std;
most_games = 0;
most_games_node = NULL;
most_games_arc = NULL;
for (arc = tree.nodes[0].child; arc; arc = arc->next) {
node = arc->node;
if (most_games < node->games) {
most_games = node->games;
most_games_node = node;
most_games_arc = arc;
}
}
if (most_games == 0)
break;
mean = most_games_node->sum_scores / most_games_node->games;
std = sqrt((most_games_node->sum_scores2 - most_games_node->sum_scores * mean) / (most_games_node->games - 1));
gprintf("%1m ", most_games_arc->move);
fprintf(stderr, "%6d %6d %5.3f %5.3f %5.3f %5.3f\n",
most_games_node->wins, most_games_node->games,
(float) most_games_node->wins / most_games_node->games,
mean, std, mean / (std + 0.001));
most_games_node->games = -most_games_node->games;
}
for (arc = tree.nodes[0].child; arc; arc = arc->next)
arc->node->games = -arc->node->games;
{
int n;
struct uct_arc *arcs[7];
int depth = 0;
n = uct_find_best_children(&tree.nodes[0], arcs, 7);
gprintf("Principal variation:\n");
while (n > 0 && depth < 80) {
int k;
gprintf("%C ", color);
for (k = 0; k < n; k++) {
node = arcs[k]->node;
gprintf("%1m ", arcs[k]->move);
fprintf(stderr, "%5.3f", (float) node->wins / node->games);
if (k == 0)
gprintf(" (%d games)", node->games);
if (k < n - 1)
gprintf(", ");
}
gprintf("\n");
color = OTHER_COLOR(color);
n = uct_find_best_children(arcs[0]->node, arcs, 7);
depth++;
}
gprintf("\n");
}
}
free(tree.nodes);
free(tree.arcs);
free(tree.hashtable_odd);
free(tree.hashtable_even);
}
/*
* Local Variables:
* tab-width: 8
* c-basic-offset: 2
* End:
*/
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