void
uct_progress_text(struct uct *u, struct tree *t, enum stone color, int playouts)
{
if (!UDEBUGL(0))
return;
/* Best move */
struct tree_node *best = u->policy->choose(u->policy, t->root, t->board, color, resign);
if (!best) {
fprintf(stderr, "... No moves left\n");
return;
}
fprintf(stderr, "[%d] ", playouts);
fprintf(stderr, "best %f ", tree_node_get_value(t, 1, best->u.value));
/* Dynamic komi */
if (t->use_extra_komi)
fprintf(stderr, "xkomi %.1f ", t->extra_komi);
/* Best sequence */
fprintf(stderr, "| seq ");
for (int depth = 0; depth < 4; depth++) {
if (best && best->u.playouts >= 25) {
fprintf(stderr, "%3s ", coord2sstr(node_coord(best), t->board));
best = u->policy->choose(u->policy, best, t->board, color, resign);
} else {
fprintf(stderr, " ");
}
}
/* Best candidates */
fprintf(stderr, "| can %c ", color == S_BLACK ? 'b' : 'w');
int cans = 4;
struct tree_node *can[cans];
memset(can, 0, sizeof(can));
best = t->root->children;
while (best) {
int c = 0;
while ((!can[c] || best->u.playouts > can[c]->u.playouts) && ++c < cans);
for (int d = 0; d < c; d++) can[d] = can[d + 1];
if (c > 0) can[c - 1] = best;
best = best->sibling;
}
while (--cans >= 0) {
if (can[cans]) {
fprintf(stderr, "%3s(%.3f) ",
coord2sstr(node_coord(can[cans]), t->board),
tree_node_get_value(t, 1, can[cans]->u.value));
} else {
fprintf(stderr, " ");
}
}
fprintf(stderr, "\n");
}
int
uct_playout(struct uct *u, struct board *b, enum stone player_color, struct tree *t)
{
struct board b2;
board_copy(&b2, b);
struct playout_amafmap amaf;
amaf.gamelen = amaf.game_baselen = 0;
/* Walk the tree until we find a leaf, then expand it and do
* a random playout. */
struct tree_node *n = t->root;
enum stone node_color = stone_other(player_color);
assert(node_color == t->root_color);
/* Make sure the root node is expanded. */
if (tree_leaf_node(n) && !__sync_lock_test_and_set(&n->is_expanded, 1))
tree_expand_node(t, n, &b2, player_color, u, 1);
/* Tree descent history. */
/* XXX: This is somewhat messy since @n and descent[dlen-1].node are
* redundant. */
struct uct_descent descent[DESCENT_DLEN];
descent[0].node = n; descent[0].lnode = NULL;
int dlen = 1;
/* Total value of the sequence. */
struct move_stats seq_value = { .playouts = 0 };
/* The last "significant" node along the descent (i.e. node
* with higher than configured number of playouts). For black
* and white. */
struct tree_node *significant[2] = { NULL, NULL };
if (n->u.playouts >= u->significant_threshold)
significant[node_color - 1] = n;
int result;
int pass_limit = (board_size(&b2) - 2) * (board_size(&b2) - 2) / 2;
int passes = is_pass(b->last_move.coord) && b->moves > 0;
/* debug */
static char spaces[] = "\0 ";
/* /debug */
if (UDEBUGL(8))
fprintf(stderr, "--- UCT walk with color %d\n", player_color);
while (!tree_leaf_node(n) && passes < 2) {
spaces[dlen - 1] = ' '; spaces[dlen] = 0;
/*** Choose a node to descend to: */
/* Parity is chosen already according to the child color, since
* it is applied to children. */
node_color = stone_other(node_color);
int parity = (node_color == player_color ? 1 : -1);
assert(dlen < DESCENT_DLEN);
descent[dlen] = descent[dlen - 1];
if (u->local_tree && (!descent[dlen].lnode || descent[dlen].node->d >= u->tenuki_d)) {
/* Start new local sequence. */
/* Remember that node_color already holds color of the
* to-be-found child. */
descent[dlen].lnode = node_color == S_BLACK ? t->ltree_black : t->ltree_white;
}
if (!u->random_policy_chance || fast_random(u->random_policy_chance))
u->policy->descend(u->policy, t, &descent[dlen], parity, b2.moves > pass_limit);
else
u->random_policy->descend(u->random_policy, t, &descent[dlen], parity, b2.moves > pass_limit);
/*** Perform the descent: */
if (descent[dlen].node->u.playouts >= u->significant_threshold) {
significant[node_color - 1] = descent[dlen].node;
}
seq_value.playouts += descent[dlen].value.playouts;
seq_value.value += descent[dlen].value.value * descent[dlen].value.playouts;
n = descent[dlen++].node;
assert(n == t->root || n->parent);
if (UDEBUGL(7))
fprintf(stderr, "%s+-- UCT sent us to [%s:%d] %d,%f\n",
spaces, coord2sstr(node_coord(n), t->board),
node_coord(n), n->u.playouts,
tree_node_get_value(t, parity, n->u.value));
/* Add virtual loss if we need to; this is used to discourage
* other threads from visiting this node in case of multiple
* threads doing the tree search. */
if (u->virtual_loss)
stats_add_result(&n->u, node_color == S_BLACK ? 0.0 : 1.0, u->virtual_loss);
assert(node_coord(n) >= -1);
record_amaf_move(&amaf, node_coord(n));
struct move m = { node_coord(n), node_color };
int res = board_play(&b2, &m);
if (res < 0 || (!is_pass(m.coord) && !group_at(&b2, m.coord)) /* suicide */
|| b2.superko_violation) {
if (UDEBUGL(4)) {
for (struct tree_node *ni = n; ni; ni = ni->parent)
fprintf(stderr, "%s<%"PRIhash"> ", coord2sstr(node_coord(ni), t->board), ni->hash);
fprintf(stderr, "marking invalid %s node %d,%d res %d group %d spk %d\n",
stone2str(node_color), coord_x(node_coord(n),b), coord_y(node_coord(n),b),
res, group_at(&b2, m.coord), b2.superko_violation);
}
n->hints |= TREE_HINT_INVALID;
result = 0;
goto end;
}
if (is_pass(node_coord(n)))
passes++;
else
passes = 0;
enum stone next_color = stone_other(node_color);
/* We need to make sure only one thread expands the node. If
* we are unlucky enough for two threads to meet in the same
* node, the latter one will simply do another simulation from
* the node itself, no big deal. t->nodes_size may exceed
* the maximum in multi-threaded case but not by much so it's ok.
* The size test must be before the test&set not after, to allow
* expansion of the node later if enough nodes have been freed. */
if (tree_leaf_node(n)
&& n->u.playouts - u->virtual_loss >= u->expand_p && t->nodes_size < u->max_tree_size
&& !__sync_lock_test_and_set(&n->is_expanded, 1))
tree_expand_node(t, n, &b2, next_color, u, -parity);
}
amaf.game_baselen = amaf.gamelen;
if (t->use_extra_komi && u->dynkomi->persim) {
b2.komi += round(u->dynkomi->persim(u->dynkomi, &b2, t, n));
}
if (passes >= 2) {
/* XXX: No dead groups support. */
floating_t score = board_official_score(&b2, NULL);
/* Result from black's perspective (no matter who
* the player; black's perspective is always
* what the tree stores. */
result = - (score * 2);
if (UDEBUGL(5))
fprintf(stderr, "[%d..%d] %s p-p scoring playout result %d (W %f)\n",
player_color, node_color, coord2sstr(node_coord(n), t->board), result, score);
if (UDEBUGL(6))
board_print(&b2, stderr);
board_ownermap_fill(&u->ownermap, &b2);
} else { // assert(tree_leaf_node(n));
/* In case of parallel tree search, the assertion might
* not hold if two threads chew on the same node. */
result = uct_leaf_node(u, &b2, player_color, &amaf, descent, &dlen, significant, t, n, node_color, spaces);
}
if (u->policy->wants_amaf && u->playout_amaf_cutoff) {
unsigned int cutoff = amaf.game_baselen;
cutoff += (amaf.gamelen - amaf.game_baselen) * u->playout_amaf_cutoff / 100;
amaf.gamelen = cutoff;
}
/* Record the result. */
assert(n == t->root || n->parent);
floating_t rval = scale_value(u, b, result);
u->policy->update(u->policy, t, n, node_color, player_color, &amaf, &b2, rval);
if (t->use_extra_komi) {
stats_add_result(&u->dynkomi->score, result / 2, 1);
stats_add_result(&u->dynkomi->value, rval, 1);
}
if (u->local_tree && n->parent && !is_pass(node_coord(n)) && dlen > 0) {
/* Get the local sequences and record them in ltree. */
/* We will look for sequence starts in our descent
* history, then run record_local_sequence() for each
* found sequence start; record_local_sequence() may
* pick longer sequences from descent history then,
* which is expected as it will create new lnodes. */
enum stone seq_color = player_color;
/* First move always starts a sequence. */
record_local_sequence(u, t, &b2, descent, dlen, 1, seq_color);
seq_color = stone_other(seq_color);
for (int dseqi = 2; dseqi < dlen; dseqi++, seq_color = stone_other(seq_color)) {
if (u->local_tree_allseq) {
/* We are configured to record all subsequences. */
record_local_sequence(u, t, &b2, descent, dlen, dseqi, seq_color);
continue;
}
if (descent[dseqi].node->d >= u->tenuki_d) {
/* Tenuki! Record the fresh sequence. */
record_local_sequence(u, t, &b2, descent, dlen, dseqi, seq_color);
continue;
}
if (descent[dseqi].lnode && !descent[dseqi].lnode) {
/* Record result for in-descent picked sequence. */
record_local_sequence(u, t, &b2, descent, dlen, dseqi, seq_color);
continue;
}
}
}
end:
/* We need to undo the virtual loss we added during descend. */
if (u->virtual_loss) {
floating_t loss = node_color == S_BLACK ? 0.0 : 1.0;
for (; n->parent; n = n->parent) {
stats_rm_result(&n->u, loss, u->virtual_loss);
loss = 1.0 - loss;
}
}
board_done_noalloc(&b2);
return result;
}
int
uct_playouts(struct uct *u, struct board *b, enum stone color, struct tree *t, struct time_info *ti)
{
int i;
if (ti && ti->dim == TD_GAMES) {
for (i = 0; t->root->u.playouts <= ti->len.games && !uct_halt; i++)
uct_playout(u, b, color, t);
} else {
for (i = 0; !uct_halt; i++)
uct_playout(u, b, color, t);
}
return i;
}
static int
uct_leaf_node(struct uct *u, struct board *b, enum stone player_color,
struct playout_amafmap *amaf,
struct uct_descent *descent, int *dlen,
struct tree_node *significant[2],
struct tree *t, struct tree_node *n, enum stone node_color,
char *spaces)
{
enum stone next_color = stone_other(node_color);
int parity = (next_color == player_color ? 1 : -1);
if (UDEBUGL(7))
fprintf(stderr, "%s*-- UCT playout #%d start [%s] %f\n",
spaces, n->u.playouts, coord2sstr(node_coord(n), t->board),
tree_node_get_value(t, parity, n->u.value));
struct uct_playout_callback upc = {
.uct = u,
.tree = t,
/* TODO: Don't necessarily restart the sequence walk when
* entering playout. */
.lnode = NULL,
};
struct playout_setup ps = {
.gamelen = u->gamelen,
.mercymin = u->mercymin,
.prepolicy_hook = uct_playout_prepolicy,
.postpolicy_hook = uct_playout_postpolicy,
.hook_data = &upc,
};
int result = play_random_game(&ps, b, next_color,
u->playout_amaf ? amaf : NULL,
&u->ownermap, u->playout);
if (next_color == S_WHITE) {
/* We need the result from black's perspective. */
result = - result;
}
if (UDEBUGL(7))
fprintf(stderr, "%s -- [%d..%d] %s random playout result %d\n",
spaces, player_color, next_color, coord2sstr(node_coord(n), t->board), result);
return result;
}
static floating_t
scale_value(struct uct *u, struct board *b, int result)
{
floating_t rval = result > 0 ? 1.0 : result < 0 ? 0.0 : 0.5;
if (u->val_scale && result != 0) {
int vp = u->val_points;
if (!vp) {
vp = board_size(b) - 1; vp *= vp; vp *= 2;
}
floating_t sval = (floating_t) abs(result) / vp;
sval = sval > 1 ? 1 : sval;
if (result < 0) sval = 1 - sval;
if (u->val_extra)
rval += u->val_scale * sval;
else
rval = (1 - u->val_scale) * rval + u->val_scale * sval;
// fprintf(stderr, "score %d => sval %f, rval %f\n", result, sval, rval);
}
return rval;
}
