uct/uct.c

   1 #include <assert.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <time.h>
   7
   8 #define DEBUG
   9
  10 #include "debug.h"
  11 #include "board.h"
  12 #include "gtp.h"
  13 #include "chat.h"
  14 #include "move.h"
  15 #include "mq.h"
  16 #include "joseki/base.h"
  17 #include "playout.h"
  18 #include "playout/moggy.h"
  19 #include "playout/light.h"
  20 #include "tactics/util.h"
  21 #include "timeinfo.h"
  22 #include "uct/dynkomi.h"
  23 #include "uct/internal.h"
  24 #include "uct/plugins.h"
  25 #include "uct/prior.h"
  26 #include "uct/search.h"
  27 #include "uct/slave.h"
  28 #include "uct/tree.h"
  29 #include "uct/uct.h"
  30 #include "uct/walk.h"
  31
  32 struct uct_policy *policy_ucb1_init(struct uct *u, char *arg);
  33 struct uct_policy *policy_ucb1amaf_init(struct uct *u, char *arg, struct board *board);
  34 static void uct_pondering_start(struct uct *u, struct board *b0, struct tree *t, enum stone color);
  35
  36 /* Maximal simulation length. */
  37 #define MC_GAMELEN      MAX_GAMELEN
  38
  39
  40 static void
  41 setup_state(struct uct *u, struct board *b, enum stone color)
  42 {
  43         u->t = tree_init(b, color, u->fast_alloc ? u->max_tree_size : 0,
  44                          u->max_pruned_size, u->pruning_threshold, u->local_tree_aging, u->stats_hbits);
  45         if (u->force_seed)
  46                 fast_srandom(u->force_seed);
  47         if (UDEBUGL(3))
  48                 fprintf(stderr, "Fresh board with random seed %lu\n", fast_getseed());
  49         if (!u->no_tbook && b->moves == 0) {
  50                 if (color == S_BLACK) {
  51                         tree_load(u->t, b);
  52                 } else if (DEBUGL(0)) {
  53                         fprintf(stderr, "Warning: First move appears to be white\n");
  54                 }
  55         }
  56 }
  57
  58 static void
  59 reset_state(struct uct *u)
  60 {
  61         assert(u->t);
  62         tree_done(u->t); u->t = NULL;
  63 }
  64
  65 static void
  66 setup_dynkomi(struct uct *u, struct board *b, enum stone to_play)
  67 {
  68         if (u->t->use_extra_komi && !u->pondering && u->dynkomi->permove)
  69                 u->t->extra_komi = u->dynkomi->permove(u->dynkomi, b, u->t);
  70         else if (!u->t->use_extra_komi)
  71                 u->t->extra_komi = 0;
  72 }
  73
  74 void
  75 uct_prepare_move(struct uct *u, struct board *b, enum stone color)
  76 {
  77         if (u->t) {
  78                 /* Verify that we have sane state. */
  79                 assert(b->es == u);
  80                 assert(u->t && b->moves);
  81                 if (color != stone_other(u->t->root_color)) {
  82                         fprintf(stderr, "Fatal: Non-alternating play detected %d %d\n",
  83                                 color, u->t->root_color);
  84                         exit(1);
  85                 }
  86                 uct_htable_reset(u->t);
  87
  88         } else {
  89                 /* We need fresh state. */
  90                 b->es = u;
  91                 setup_state(u, b, color);
  92         }
  93
  94         u->ownermap.playouts = 0;
  95         memset(u->ownermap.map, 0, board_size2(b) * sizeof(u->ownermap.map[0]));
  96         u->played_own = u->played_all = 0;
  97 }
  98
  99 static void
 100 dead_group_list(struct uct *u, struct board *b, struct move_queue *mq)
 101 {
 102         enum gj_state gs_array[board_size2(b)];
 103         struct group_judgement gj = { .thres = GJ_THRES, .gs = gs_array };
 104         board_ownermap_judge_groups(b, &u->ownermap, &gj);
 105         groups_of_status(b, &gj, GS_DEAD, mq);
 106 }
 107
 108 bool
 109 uct_pass_is_safe(struct uct *u, struct board *b, enum stone color, bool pass_all_alive)
 110 {
 111         /* Make sure enough playouts are simulated to get a reasonable dead group list. */
 112         while (u->ownermap.playouts < GJ_MINGAMES)
 113                 uct_playout(u, b, color, u->t);
 114
 115         struct move_queue mq = { .moves = 0 };
 116         dead_group_list(u, b, &mq);
 117         if (pass_all_alive) {
 118                 for (unsigned int i = 0; i < mq.moves; i++) {
 119                         if (board_at(b, mq.move[i]) == stone_other(color)) {
 120                                 return false; // We need to remove opponent dead groups first.
 121                         }
 122                 }
 123                 mq.moves = 0; // our dead stones are alive when pass_all_alive is true
 124         }
 125         return pass_is_safe(b, color, &mq);
 126 }
 127
 128 static char *
 129 uct_printhook_ownermap(struct board *board, coord_t c, char *s, char *end)
 130 {
 131         struct uct *u = board->es;
 132         if (!u) {
 133                 strcat(s, ". ");
 134                 return s + 2;
 135         }
 136         const char chr[] = ":XO,"; // dame, black, white, unclear
 137         const char chm[] = ":xo,";
 138         char ch = chr[board_ownermap_judge_point(&u->ownermap, c, GJ_THRES)];
 139         if (ch == ',') { // less precise estimate then?
 140                 ch = chm[board_ownermap_judge_point(&u->ownermap, c, 0.67)];
 141         }
 142         s += snprintf(s, end - s, "%c ", ch);
 143         return s;
 144 }
 145
 146 static char *
 147 uct_notify_play(struct engine *e, struct board *b, struct move *m, char *enginearg)
 148 {
 149         struct uct *u = e->data;
 150         if (!u->t) {
 151                 /* No state, create one - this is probably game beginning
 152                  * and we need to load the opening tbook right now. */
 153                 uct_prepare_move(u, b, m->color);
 154                 assert(u->t);
 155         }
 156
 157         /* Stop pondering, required by tree_promote_at() */
 158         uct_pondering_stop(u);
 159         if (UDEBUGL(2) && u->slave)
 160                 tree_dump(u->t, u->dumpthres);
 161
 162         if (is_resign(m->coord)) {
 163                 /* Reset state. */
 164                 reset_state(u);
 165                 return NULL;
 166         }
 167
 168         /* Promote node of the appropriate move to the tree root. */
 169         assert(u->t->root);
 170         if (!tree_promote_at(u->t, b, m->coord)) {
 171                 if (UDEBUGL(3))
 172                         fprintf(stderr, "Warning: Cannot promote move node! Several play commands in row?\n");
 173                 reset_state(u);
 174                 return NULL;
 175         }
 176
 177         /* If we are a slave in a distributed engine, start pondering once
 178          * we know which move we actually played. See uct_genmove() about
 179          * the check for pass. */
 180         if (u->pondering_opt && u->slave && m->color == u->my_color && !is_pass(m->coord))
 181                 uct_pondering_start(u, b, u->t, stone_other(m->color));
 182
 183         return NULL;
 184 }
 185
 186 static char *
 187 uct_undo(struct engine *e, struct board *b)
 188 {
 189         struct uct *u = e->data;
 190
 191         if (!u->t) return NULL;
 192         uct_pondering_stop(u);
 193         reset_state(u);
 194         return NULL;
 195 }
 196
 197 static char *
 198 uct_result(struct engine *e, struct board *b)
 199 {
 200         struct uct *u = e->data;
 201         static char reply[1024];
 202
 203         if (!u->t)
 204                 return NULL;
 205         enum stone color = u->t->root_color;
 206         struct tree_node *n = u->t->root;
 207         snprintf(reply, 1024, "%s %s %d %.2f %.1f",
 208                  stone2str(color), coord2sstr(node_coord(n), b),
 209                  n->u.playouts, tree_node_get_value(u->t, -1, n->u.value),
 210                  u->t->use_extra_komi ? u->t->extra_komi : 0);
 211         return reply;
 212 }
 213
 214 static char *
 215 uct_chat(struct engine *e, struct board *b, bool opponent, char *from, char *cmd)
 216 {
 217         struct uct *u = e->data;
 218
 219         if (!u->t)
 220                 return generic_chat(b, opponent, from, cmd, S_NONE, pass, 0, 1, u->threads, 0.0, 0.0);
 221
 222         struct tree_node *n = u->t->root;
 223         double winrate = tree_node_get_value(u->t, -1, n->u.value);
 224         double extra_komi = u->t->use_extra_komi && abs(u->t->extra_komi) >= 0.5 ? u->t->extra_komi : 0;
 225
 226         return generic_chat(b, opponent, from, cmd, u->t->root_color, node_coord(n), n->u.playouts, 1,
 227                             u->threads, winrate, extra_komi);
 228 }
 229
 230 static void
 231 uct_dead_group_list(struct engine *e, struct board *b, struct move_queue *mq)
 232 {
 233         struct uct *u = e->data;
 234
 235         /* This means the game is probably over, no use pondering on. */
 236         uct_pondering_stop(u);
 237
 238         if (u->pass_all_alive)
 239                 return; // no dead groups
 240
 241         bool mock_state = false;
 242
 243         if (!u->t) {
 244                 /* No state, but we cannot just back out - we might
 245                  * have passed earlier, only assuming some stones are
 246                  * dead, and then re-connected, only to lose counting
 247                  * when all stones are assumed alive. */
 248                 uct_prepare_move(u, b, S_BLACK); assert(u->t);
 249                 mock_state = true;
 250         }
 251         /* Make sure the ownermap is well-seeded. */
 252         while (u->ownermap.playouts < GJ_MINGAMES)
 253                 uct_playout(u, b, S_BLACK, u->t);
 254         /* Show the ownermap: */
 255         if (DEBUGL(2))
 256                 board_print_custom(b, stderr, uct_printhook_ownermap);
 257
 258         dead_group_list(u, b, mq);
 259
 260         if (mock_state) {
 261                 /* Clean up the mock state in case we will receive
 262                  * a genmove; we could get a non-alternating-move
 263                  * error from uct_prepare_move() in that case otherwise. */
 264                 reset_state(u);
 265         }
 266 }
 267
 268 static void
 269 playout_policy_done(struct playout_policy *p)
 270 {
 271         if (p->done) p->done(p);
 272         if (p->data) free(p->data);
 273         free(p);
 274 }
 275
 276 static void
 277 uct_done(struct engine *e)
 278 {
 279         /* This is called on engine reset, especially when clear_board
 280          * is received and new game should begin. */
 281         struct uct *u = e->data;
 282         uct_pondering_stop(u);
 283         if (u->t) reset_state(u);
 284         free(u->ownermap.map);
 285
 286         free(u->policy);
 287         free(u->random_policy);
 288         playout_policy_done(u->playout);
 289         uct_prior_done(u->prior);
 290         joseki_done(u->jdict);
 291         pluginset_done(u->plugins);
 292 }
 293
 294
 295
 296 /* Run time-limited MCTS search on foreground. */
 297 static int
 298 uct_search(struct uct *u, struct board *b, struct time_info *ti, enum stone color, struct tree *t)
 299 {
 300         struct uct_search_state s;
 301         uct_search_start(u, b, color, t, ti, &s);
 302         if (UDEBUGL(2) && s.base_playouts > 0)
 303                 fprintf(stderr, "<pre-simulated %d games>\n", s.base_playouts);
 304
 305         /* The search tree is ctx->t. This is currently == . It is important
 306          * to reference ctx->t directly since the
 307          * thread manager will swap the tree pointer asynchronously. */
 308
 309         /* Now, just periodically poll the search tree. */
 310         /* Note that in case of TD_GAMES, threads will not wait for
 311          * the uct_search_check_stop() signalization. */
 312         while (1) {
 313                 time_sleep(TREE_BUSYWAIT_INTERVAL);
 314                 /* TREE_BUSYWAIT_INTERVAL should never be less than desired time, or the
 315                  * time control is broken. But if it happens to be less, we still search
 316                  * at least 100ms otherwise the move is completely random. */
 317
 318                 int i = uct_search_games(&s);
 319                 /* Print notifications etc. */
 320                 uct_search_progress(u, b, color, t, ti, &s, i);
 321                 /* Check if we should stop the search. */
 322                 if (uct_search_check_stop(u, b, color, t, ti, &s, i))
 323                         break;
 324         }
 325
 326         struct uct_thread_ctx *ctx = uct_search_stop();
 327         if (UDEBUGL(2)) tree_dump(t, u->dumpthres);
 328         if (UDEBUGL(2))
 329                 fprintf(stderr, "(avg score %f/%d; dynkomi's %f/%d value %f/%d)\n",
 330                         t->avg_score.value, t->avg_score.playouts,
 331                         u->dynkomi->score.value, u->dynkomi->score.playouts,
 332                         u->dynkomi->value.value, u->dynkomi->value.playouts);
 333         uct_progress_status(u, t, color, ctx->games, true);
 334
 335         u->played_own += ctx->games;
 336         return ctx->games;
 337 }
 338
 339 /* Start pondering background with @color to play. */
 340 static void
 341 uct_pondering_start(struct uct *u, struct board *b0, struct tree *t, enum stone color)
 342 {
 343         if (UDEBUGL(1))
 344                 fprintf(stderr, "Starting to ponder with color %s\n", stone2str(stone_other(color)));
 345         u->pondering = true;
 346
 347         /* We need a local board copy to ponder upon. */
 348         struct board *b = malloc2(sizeof(*b)); board_copy(b, b0);
 349
 350         /* *b0 did not have the genmove'd move played yet. */
 351         struct move m = { node_coord(t->root), t->root_color };
 352         int res = board_play(b, &m);
 353         assert(res >= 0);
 354         setup_dynkomi(u, b, stone_other(m.color));
 355
 356         /* Start MCTS manager thread "headless". */
 357         static struct uct_search_state s;
 358         uct_search_start(u, b, color, t, NULL, &s);
 359 }
 360
 361 /* uct_search_stop() frontend for the pondering (non-genmove) mode, and
 362  * to stop the background search for a slave in the distributed engine. */
 363 void
 364 uct_pondering_stop(struct uct *u)
 365 {
 366         if (!thread_manager_running)
 367                 return;
 368
 369         /* Stop the thread manager. */
 370         struct uct_thread_ctx *ctx = uct_search_stop();
 371         if (UDEBUGL(1)) {
 372                 if (u->pondering) fprintf(stderr, "(pondering) ");
 373                 uct_progress_status(u, ctx->t, ctx->color, ctx->games, true);
 374         }
 375         if (u->pondering) {
 376                 free(ctx->b);
 377                 u->pondering = false;
 378         }
 379 }
 380
 381
 382 void
 383 uct_genmove_setup(struct uct *u, struct board *b, enum stone color)
 384 {
 385         if (b->superko_violation) {
 386                 fprintf(stderr, "!!! WARNING: SUPERKO VIOLATION OCCURED BEFORE THIS MOVE\n");
 387                 fprintf(stderr, "Maybe you play with situational instead of positional superko?\n");
 388                 fprintf(stderr, "I'm going to ignore the violation, but note that I may miss\n");
 389                 fprintf(stderr, "some moves valid under this ruleset because of this.\n");
 390                 b->superko_violation = false;
 391         }
 392
 393         uct_prepare_move(u, b, color);
 394
 395         assert(u->t);
 396         u->my_color = color;
 397
 398         /* How to decide whether to use dynkomi in this game? Since we use
 399          * pondering, it's not simple "who-to-play" matter. Decide based on
 400          * the last genmove issued. */
 401         u->t->use_extra_komi = !!(u->dynkomi_mask & color);
 402         setup_dynkomi(u, b, color);
 403
 404         if (b->rules == RULES_JAPANESE)
 405                 u->territory_scoring = true;
 406
 407         /* Make pessimistic assumption about komi for Japanese rules to
 408          * avoid losing by 0.5 when winning by 0.5 with Chinese rules.
 409          * The rules usually give the same winner if the integer part of komi
 410          * is odd so we adjust the komi only if it is even (for a board of
 411          * odd size). We are not trying  to get an exact evaluation for rare
 412          * cases of seki. For details see http://home.snafu.de/jasiek/parity.html */
 413         if (u->territory_scoring && (((int)floor(b->komi) + board_size(b)) & 1)) {
 414                 b->komi += (color == S_BLACK ? 1.0 : -1.0);
 415                 if (UDEBUGL(0))
 416                         fprintf(stderr, "Setting komi to %.1f assuming Japanese rules\n",
 417                                 b->komi);
 418         }
 419 }
 420
 421 static coord_t *
 422 uct_genmove(struct engine *e, struct board *b, struct time_info *ti, enum stone color, bool pass_all_alive)
 423 {
 424         double start_time = time_now();
 425         struct uct *u = e->data;
 426         u->pass_all_alive |= pass_all_alive;
 427         uct_pondering_stop(u);
 428         uct_genmove_setup(u, b, color);
 429
 430         /* Start the Monte Carlo Tree Search! */
 431         int base_playouts = u->t->root->u.playouts;
 432         int played_games = uct_search(u, b, ti, color, u->t);
 433
 434         coord_t best_coord;
 435         struct tree_node *best;
 436         best = uct_search_result(u, b, color, u->pass_all_alive, played_games, base_playouts, &best_coord);
 437
 438         if (UDEBUGL(2)) {
 439                 double time = time_now() - start_time + 0.000001; /* avoid divide by zero */
 440                 fprintf(stderr, "genmove in %0.2fs (%d games/s, %d games/s/thread)\n",
 441                         time, (int)(played_games/time), (int)(played_games/time/u->threads));
 442         }
 443
 444         if (!best) {
 445                 /* Pass or resign. */
 446                 reset_state(u);
 447                 return coord_copy(best_coord);
 448         }
 449         tree_promote_node(u->t, &best);
 450
 451         /* After a pass, pondering is harmful for two reasons:
 452          * (i) We might keep pondering even when the game is over.
 453          * Of course this is the case for opponent resign as well.
 454          * (ii) More importantly, the ownermap will get skewed since
 455          * the UCT will start cutting off any playouts. */
 456         if (u->pondering_opt && !is_pass(node_coord(best))) {
 457                 uct_pondering_start(u, b, u->t, stone_other(color));
 458         }
 459         return coord_copy(best_coord);
 460 }
 461
 462
 463 bool
 464 uct_gentbook(struct engine *e, struct board *b, struct time_info *ti, enum stone color)
 465 {
 466         struct uct *u = e->data;
 467         if (!u->t) uct_prepare_move(u, b, color);
 468         assert(u->t);
 469
 470         if (ti->dim == TD_GAMES) {
 471                 /* Don't count in games that already went into the tbook. */
 472                 ti->len.games += u->t->root->u.playouts;
 473         }
 474         uct_search(u, b, ti, color, u->t);
 475
 476         assert(ti->dim == TD_GAMES);
 477         tree_save(u->t, b, ti->len.games / 100);
 478
 479         return true;
 480 }
 481
 482 void
 483 uct_dumptbook(struct engine *e, struct board *b, enum stone color)
 484 {
 485         struct uct *u = e->data;
 486         struct tree *t = tree_init(b, color, u->fast_alloc ? u->max_tree_size : 0,
 487                          u->max_pruned_size, u->pruning_threshold, u->local_tree_aging, 0);
 488         tree_load(t, b);
 489         tree_dump(t, 0);
 490         tree_done(t);
 491 }
 492
 493
 494 floating_t
 495 uct_evaluate_one(struct engine *e, struct board *b, struct time_info *ti, coord_t c, enum stone color)
 496 {
 497         struct uct *u = e->data;
 498
 499         struct board b2;
 500         board_copy(&b2, b);
 501         struct move m = { c, color };
 502         int res = board_play(&b2, &m);
 503         if (res < 0)
 504                 return NAN;
 505         color = stone_other(color);
 506
 507         if (u->t) reset_state(u);
 508         uct_prepare_move(u, &b2, color);
 509         assert(u->t);
 510
 511         floating_t bestval;
 512         uct_search(u, &b2, ti, color, u->t);
 513         struct tree_node *best = u->policy->choose(u->policy, u->t->root, &b2, color, resign);
 514         if (!best) {
 515                 bestval = NAN; // the opponent has no reply!
 516         } else {
 517                 bestval = tree_node_get_value(u->t, 1, best->u.value);
 518         }
 519
 520         reset_state(u); // clean our junk
 521
 522         return isnan(bestval) ? NAN : 1.0f - bestval;
 523 }
 524
 525 void
 526 uct_evaluate(struct engine *e, struct board *b, struct time_info *ti, floating_t *vals, enum stone color)
 527 {
 528         for (int i = 0; i < b->flen; i++) {
 529                 if (is_pass(b->f[i]))
 530                         vals[i] = NAN;
 531                 else
 532                         vals[i] = uct_evaluate_one(e, b, ti, b->f[i], color);
 533         }
 534 }
 535
 536
 537 struct uct *
 538 uct_state_init(char *arg, struct board *b)
 539 {
 540         struct uct *u = calloc2(1, sizeof(struct uct));
 541         bool pat_setup = false;
 542
 543         u->debug_level = debug_level;
 544         u->reportfreq = 10000;
 545         u->gamelen = MC_GAMELEN;
 546         u->resign_threshold = 0.2;
 547         u->sure_win_threshold = 0.9;
 548         u->mercymin = 0;
 549         u->significant_threshold = 50;
 550         u->expand_p = 8;
 551         u->dumpthres = 1000;
 552         u->playout_amaf = true;
 553         u->amaf_prior = false;
 554         u->max_tree_size = 1408ULL * 1048576;
 555         u->fast_alloc = true;
 556         u->pruning_threshold = 0;
 557
 558         u->threads = 1;
 559         u->thread_model = TM_TREEVL;
 560         u->virtual_loss = 1;
 561
 562         u->fuseki_end = 20; // max time at 361*20% = 72 moves (our 36th move, still 99 to play)
 563         u->yose_start = 40; // (100-40-25)*361/100/2 = 63 moves still to play by us then
 564         u->bestr_ratio = 0.02;
 565         // 2.5 is clearly too much, but seems to compensate well for overly stern time allocations.
 566         // TODO: Further tuning and experiments with better time allocation schemes.
 567         u->best2_ratio = 2.5;
 568         u->max_maintime_ratio = 3.0;
 569
 570         u->val_scale = 0; u->val_points = 40;
 571         u->dynkomi_interval = 1000;
 572         u->dynkomi_mask = S_BLACK | S_WHITE;
 573
 574         u->tenuki_d = 4;
 575         u->local_tree_aging = 80;
 576         u->local_tree_depth_decay = 1.5;
 577         u->local_tree_eval = LTE_ROOT;
 578         u->local_tree_neival = true;
 579
 580         u->max_slaves = -1;
 581         u->slave_index = -1;
 582         u->stats_delay = 0.01; // 10 ms
 583
 584         u->plugins = pluginset_init(b);
 585
 586         u->jdict = joseki_load(b->size);
 587
 588         if (arg) {
 589                 char *optspec, *next = arg;
 590                 while (*next) {
 591                         optspec = next;
 592                         next += strcspn(next, ",");
 593                         if (*next) { *next++ = 0; } else { *next = 0; }
 594
 595                         char *optname = optspec;
 596                         char *optval = strchr(optspec, '=');
 597                         if (optval) *optval++ = 0;
 598
 599                         /** Basic options */
 600
 601                         if (!strcasecmp(optname, "debug")) {
 602                                 if (optval)
 603                                         u->debug_level = atoi(optval);
 604                                 else
 605                                         u->debug_level++;
 606                         } else if (!strcasecmp(optname, "reporting") && optval) {
 607                                 /* The format of output for detailed progress
 608                                  * information (such as current best move and
 609                                  * its value, etc.). */
 610                                 if (!strcasecmp(optval, "text")) {
 611                                         /* Plaintext traditional output. */
 612                                         u->reporting = UR_TEXT;
 613                                 } else if (!strcasecmp(optval, "json")) {
 614                                         /* JSON output. Implies debug=0. */
 615                                         u->reporting = UR_JSON;
 616                                         u->debug_level = 0;
 617                                 } else if (!strcasecmp(optval, "jsonbig")) {
 618                                         /* JSON output, but much more detailed.
 619                                          * Implies debug=0. */
 620                                         u->reporting = UR_JSON_BIG;
 621                                         u->debug_level = 0;
 622                                 } else {
 623                                         fprintf(stderr, "UCT: Invalid reporting format %s\n", optval);
 624                                         exit(1);
 625                                 }
 626                         } else if (!strcasecmp(optname, "reportfreq") && optval) {
 627                                 /* The progress information line will be shown
 628                                  * every <reportfreq> simulations. */
 629                                 u->reportfreq = atoi(optval);
 630                         } else if (!strcasecmp(optname, "dumpthres") && optval) {
 631                                 /* When dumping the UCT tree on output, include
 632                                  * nodes with at least this many playouts.
 633                                  * (This value is re-scaled "intelligently"
 634                                  * in case of very large trees.) */
 635                                 u->dumpthres = atoi(optval);
 636                         } else if (!strcasecmp(optname, "resign_threshold") && optval) {
 637                                 /* Resign when this ratio of games is lost
 638                                  * after GJ_MINGAMES sample is taken. */
 639                                 u->resign_threshold = atof(optval);
 640                         } else if (!strcasecmp(optname, "sure_win_threshold") && optval) {
 641                                 /* Stop reading when this ratio of games is won
 642                                  * after PLAYOUT_EARLY_BREAK_MIN sample is
 643                                  * taken. (Prevents stupid time losses,
 644                                  * friendly to human opponents.) */
 645                                 u->sure_win_threshold = atof(optval);
 646                         } else if (!strcasecmp(optname, "force_seed") && optval) {
 647                                 /* Set RNG seed at the tree setup. */
 648                                 u->force_seed = atoi(optval);
 649                         } else if (!strcasecmp(optname, "no_tbook")) {
 650                                 /* Disable UCT opening tbook. */
 651                                 u->no_tbook = true;
 652                         } else if (!strcasecmp(optname, "pass_all_alive")) {
 653                                 /* Whether to consider passing only after all
 654                                  * dead groups were removed from the board;
 655                                  * this is like all genmoves are in fact
 656                                  * kgs-genmove_cleanup. */
 657                                 u->pass_all_alive = !optval || atoi(optval);
 658                         } else if (!strcasecmp(optname, "territory_scoring")) {
 659                                 /* Use territory scoring (default is area scoring).
 660                                  * An explicit kgs-rules command overrides this. */
 661                                 u->territory_scoring = !optval || atoi(optval);
 662                         } else if (!strcasecmp(optname, "stones_only")) {
 663                                 /* Do not count eyes. Nice to teach go to kids.
 664                                  * http://strasbourg.jeudego.org/regle_strasbourgeoise.htm */
 665                                 b->rules = RULES_STONES_ONLY;
 666                                 u->pass_all_alive = true;
 667                         } else if (!strcasecmp(optname, "banner") && optval) {
 668                                 /* Additional banner string. This must come as the
 669                                  * last engine parameter. */
 670                                 if (*next) *--next = ',';
 671                                 u->banner = strdup(optval);
 672                                 break;
 673                         } else if (!strcasecmp(optname, "plugin") && optval) {
 674                                 /* Load an external plugin; filename goes before the colon,
 675                                  * extra arguments after the colon. */
 676                                 char *pluginarg = strchr(optval, ':');
 677                                 if (pluginarg)
 678                                         *pluginarg++ = 0;
 679                                 plugin_load(u->plugins, optval, pluginarg);
 680
 681                         /** UCT behavior and policies */
 682
 683                         } else if ((!strcasecmp(optname, "policy")
 684                                 /* Node selection policy. ucb1amaf is the
 685                                  * default policy implementing RAVE, while
 686                                  * ucb1 is the simple exploration/exploitation
 687                                  * policy. Policies can take further extra
 688                                  * options. */
 689                                     || !strcasecmp(optname, "random_policy")) && optval) {
 690                                 /* A policy to be used randomly with small
 691                                  * chance instead of the default policy. */
 692                                 char *policyarg = strchr(optval, ':');
 693                                 struct uct_policy **p = !strcasecmp(optname, "policy") ? &u->policy : &u->random_policy;
 694                                 if (policyarg)
 695                                         *policyarg++ = 0;
 696                                 if (!strcasecmp(optval, "ucb1")) {
 697                                         *p = policy_ucb1_init(u, policyarg);
 698                                 } else if (!strcasecmp(optval, "ucb1amaf")) {
 699                                         *p = policy_ucb1amaf_init(u, policyarg, b);
 700                                 } else {
 701                                         fprintf(stderr, "UCT: Invalid tree policy %s\n", optval);
 702                                         exit(1);
 703                                 }
 704                         } else if (!strcasecmp(optname, "playout") && optval) {
 705                                 /* Random simulation (playout) policy.
 706                                  * moggy is the default policy with large
 707                                  * amount of domain-specific knowledge and
 708                                  * heuristics. light is a simple uniformly
 709                                  * random move selection policy. */
 710                                 char *playoutarg = strchr(optval, ':');
 711                                 if (playoutarg)
 712                                         *playoutarg++ = 0;
 713                                 if (!strcasecmp(optval, "moggy")) {
 714                                         u->playout = playout_moggy_init(playoutarg, b, u->jdict);
 715                                 } else if (!strcasecmp(optval, "light")) {
 716                                         u->playout = playout_light_init(playoutarg, b);
 717                                 } else {
 718                                         fprintf(stderr, "UCT: Invalid playout policy %s\n", optval);
 719                                         exit(1);
 720                                 }
 721                         } else if (!strcasecmp(optname, "prior") && optval) {
 722                                 /* Node priors policy. When expanding a node,
 723                                  * it will seed node values heuristically
 724                                  * (most importantly, based on playout policy
 725                                  * opinion, but also with regard to other
 726                                  * things). See uct/prior.c for details.
 727                                  * Use prior=eqex=0 to disable priors. */
 728                                 u->prior = uct_prior_init(optval, b, u);
 729                         } else if (!strcasecmp(optname, "mercy") && optval) {
 730                                 /* Minimal difference of black/white captures
 731                                  * to stop playout - "Mercy Rule". Speeds up
 732                                  * hopeless playouts at the expense of some
 733                                  * accuracy. */
 734                                 u->mercymin = atoi(optval);
 735                         } else if (!strcasecmp(optname, "gamelen") && optval) {
 736                                 /* Maximum length of single simulation
 737                                  * in moves. */
 738                                 u->gamelen = atoi(optval);
 739                         } else if (!strcasecmp(optname, "expand_p") && optval) {
 740                                 /* Expand UCT nodes after it has been
 741                                  * visited this many times. */
 742                                 u->expand_p = atoi(optval);
 743                         } else if (!strcasecmp(optname, "random_policy_chance") && optval) {
 744                                 /* If specified (N), with probability 1/N, random_policy policy
 745                                  * descend is used instead of main policy descend; useful
 746                                  * if specified policy (e.g. UCB1AMAF) can make unduly biased
 747                                  * choices sometimes, you can fall back to e.g.
 748                                  * random_policy=UCB1. */
 749                                 u->random_policy_chance = atoi(optval);
 750
 751                         /** General AMAF behavior */
 752                         /* (Only relevant if the policy supports AMAF.
 753                          * More variables can be tuned as policy
 754                          * parameters.) */
 755
 756                         } else if (!strcasecmp(optname, "playout_amaf")) {
 757                                 /* Whether to include random playout moves in
 758                                  * AMAF as well. (Otherwise, only tree moves
 759                                  * are included in AMAF. Of course makes sense
 760                                  * only in connection with an AMAF policy.) */
 761                                 /* with-without: 55.5% (+-4.1) */
 762                                 if (optval && *optval == '0')
 763                                         u->playout_amaf = false;
 764                                 else
 765                                         u->playout_amaf = true;
 766                         } else if (!strcasecmp(optname, "playout_amaf_cutoff") && optval) {
 767                                 /* Keep only first N% of playout stage AMAF
 768                                  * information. */
 769                                 u->playout_amaf_cutoff = atoi(optval);
 770                         } else if (!strcasecmp(optname, "amaf_prior") && optval) {
 771                                 /* In node policy, consider prior values
 772                                  * part of the real result term or part
 773                                  * of the AMAF term? */
 774                                 u->amaf_prior = atoi(optval);
 775
 776                         /** Performance and memory management */
 777
 778                         } else if (!strcasecmp(optname, "threads") && optval) {
 779                                 /* By default, Pachi will run with only single
 780                                  * tree search thread! */
 781                                 u->threads = atoi(optval);
 782                         } else if (!strcasecmp(optname, "thread_model") && optval) {
 783                                 if (!strcasecmp(optval, "tree")) {
 784                                         /* Tree parallelization - all threads
 785                                          * grind on the same tree. */
 786                                         u->thread_model = TM_TREE;
 787                                         u->virtual_loss = 0;
 788                                 } else if (!strcasecmp(optval, "treevl")) {
 789                                         /* Tree parallelization, but also
 790                                          * with virtual losses - this discou-
 791                                          * rages most threads choosing the
 792                                          * same tree branches to read. */
 793                                         u->thread_model = TM_TREEVL;
 794                                 } else {
 795                                         fprintf(stderr, "UCT: Invalid thread model %s\n", optval);
 796                                         exit(1);
 797                                 }
 798                         } else if (!strcasecmp(optname, "virtual_loss")) {
 799                                 /* Number of virtual losses added before evaluating a node. */
 800                                 u->virtual_loss = !optval || atoi(optval);
 801                         } else if (!strcasecmp(optname, "pondering")) {
 802                                 /* Keep searching even during opponent's turn. */
 803                                 u->pondering_opt = !optval || atoi(optval);
 804                         } else if (!strcasecmp(optname, "max_tree_size") && optval) {
 805                                 /* Maximum amount of memory [MiB] consumed by the move tree.
 806                                  * For fast_alloc it includes the temp tree used for pruning.
 807                                  * Default is 3072 (3 GiB). */
 808                                 u->max_tree_size = atol(optval) * 1048576;
 809                         } else if (!strcasecmp(optname, "fast_alloc")) {
 810                                 u->fast_alloc = !optval || atoi(optval);
 811                         } else if (!strcasecmp(optname, "pruning_threshold") && optval) {
 812                                 /* Force pruning at beginning of a move if the tree consumes
 813                                  * more than this [MiB]. Default is 10% of max_tree_size.
 814                                  * Increase to reduce pruning time overhead if memory is plentiful.
 815                                  * This option is meaningful only for fast_alloc. */
 816                                 u->pruning_threshold = atol(optval) * 1048576;
 817
 818                         /** Time control */
 819
 820                         } else if (!strcasecmp(optname, "best2_ratio") && optval) {
 821                                 /* If set, prolong simulating while
 822                                  * first_best/second_best playouts ratio
 823                                  * is less than best2_ratio. */
 824                                 u->best2_ratio = atof(optval);
 825                         } else if (!strcasecmp(optname, "bestr_ratio") && optval) {
 826                                 /* If set, prolong simulating while
 827                                  * best,best_best_child values delta
 828                                  * is more than bestr_ratio. */
 829                                 u->bestr_ratio = atof(optval);
 830                         } else if (!strcasecmp(optname, "max_maintime_ratio") && optval) {
 831                                 /* If set and while not in byoyomi, prolong simulating no more than
 832                                  * max_maintime_ratio times the normal desired thinking time. */
 833                                 u->max_maintime_ratio = atof(optval);
 834                         } else if (!strcasecmp(optname, "fuseki_end") && optval) {
 835                                 /* At the very beginning it's not worth thinking
 836                                  * too long because the playout evaluations are
 837                                  * very noisy. So gradually increase the thinking
 838                                  * time up to maximum when fuseki_end percent
 839                                  * of the board has been played.
 840                                  * This only applies if we are not in byoyomi. */
 841                                 u->fuseki_end = atoi(optval);
 842                         } else if (!strcasecmp(optname, "yose_start") && optval) {
 843                                 /* When yose_start percent of the board has been
 844                                  * played, or if we are in byoyomi, stop spending
 845                                  * more time and spread the remaining time
 846                                  * uniformly.
 847                                  * Between fuseki_end and yose_start, we spend
 848                                  * a constant proportion of the remaining time
 849                                  * on each move. (yose_start should actually
 850                                  * be much earlier than when real yose start,
 851                                  * but "yose" is a good short name to convey
 852                                  * the idea.) */
 853                                 u->yose_start = atoi(optval);
 854
 855                         /** Dynamic komi */
 856
 857                         } else if (!strcasecmp(optname, "dynkomi") && optval) {
 858                                 /* Dynamic komi approach; there are multiple
 859                                  * ways to adjust komi dynamically throughout
 860                                  * play. We currently support two: */
 861                                 char *dynkomiarg = strchr(optval, ':');
 862                                 if (dynkomiarg)
 863                                         *dynkomiarg++ = 0;
 864                                 if (!strcasecmp(optval, "none")) {
 865                                         u->dynkomi = uct_dynkomi_init_none(u, dynkomiarg, b);
 866                                 } else if (!strcasecmp(optval, "linear")) {
 867                                         /* You should set dynkomi_mask=1 or a very low
 868                                          * handicap_value for white. */
 869                                         u->dynkomi = uct_dynkomi_init_linear(u, dynkomiarg, b);
 870                                 } else if (!strcasecmp(optval, "adaptive")) {
 871                                         /* There are many more knobs to
 872                                          * crank - see uct/dynkomi.c. */
 873                                         u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomiarg, b);
 874                                 } else {
 875                                         fprintf(stderr, "UCT: Invalid dynkomi mode %s\n", optval);
 876                                         exit(1);
 877                                 }
 878                         } else if (!strcasecmp(optname, "dynkomi_mask") && optval) {
 879                                 /* Bitmask of colors the player must be
 880                                  * for dynkomi be applied; the default dynkomi_mask=3 allows
 881                                  * dynkomi even in games where Pachi is white. */
 882                                 u->dynkomi_mask = atoi(optval);
 883                         } else if (!strcasecmp(optname, "dynkomi_interval") && optval) {
 884                                 /* If non-zero, re-adjust dynamic komi
 885                                  * throughout a single genmove reading,
 886                                  * roughly every N simulations. */
 887                                 /* XXX: Does not work with tree
 888                                  * parallelization. */
 889                                 u->dynkomi_interval = atoi(optval);
 890
 891                         /** Node value result scaling */
 892
 893                         } else if (!strcasecmp(optname, "val_scale") && optval) {
 894                                 /* How much of the game result value should be
 895                                  * influenced by win size. Zero means it isn't. */
 896                                 u->val_scale = atof(optval);
 897                         } else if (!strcasecmp(optname, "val_points") && optval) {
 898                                 /* Maximum size of win to be scaled into game
 899                                  * result value. Zero means boardsize^2. */
 900                                 u->val_points = atoi(optval) * 2; // result values are doubled
 901                         } else if (!strcasecmp(optname, "val_extra")) {
 902                                 /* If false, the score coefficient will be simply
 903                                  * added to the value, instead of scaling the result
 904                                  * coefficient because of it. */
 905                                 u->val_extra = !optval || atoi(optval);
 906
 907                         /** Local trees */
 908                         /* (Purely experimental. Does not work - yet!) */
 909
 910                         } else if (!strcasecmp(optname, "local_tree")) {
 911                                 /* Whether to bias exploration by local tree values. */
 912                                 u->local_tree = !optval || atoi(optval);
 913                         } else if (!strcasecmp(optname, "tenuki_d") && optval) {
 914                                 /* Tenuki distance at which to break the local tree. */
 915                                 u->tenuki_d = atoi(optval);
 916                                 if (u->tenuki_d > TREE_NODE_D_MAX + 1) {
 917                                         fprintf(stderr, "uct: tenuki_d must not be larger than TREE_NODE_D_MAX+1 %d\n", TREE_NODE_D_MAX + 1);
 918                                         exit(1);
 919                                 }
 920                         } else if (!strcasecmp(optname, "local_tree_aging") && optval) {
 921                                 /* How much to reduce local tree values between moves. */
 922                                 u->local_tree_aging = atof(optval);
 923                         } else if (!strcasecmp(optname, "local_tree_depth_decay") && optval) {
 924                                 /* With value x>0, during the descent the node
 925                                  * contributes 1/x^depth playouts in
 926                                  * the local tree. I.e., with x>1, nodes more
 927                                  * distant from local situation contribute more
 928                                  * than nodes near the root. */
 929                                 u->local_tree_depth_decay = atof(optval);
 930                         } else if (!strcasecmp(optname, "local_tree_allseq")) {
 931                                 /* If disabled, only complete sequences are stored
 932                                  * in the local tree. If this is on, also
 933                                  * subsequences starting at each move are stored. */
 934                                 u->local_tree_allseq = !optval || atoi(optval);
 935                         } else if (!strcasecmp(optname, "local_tree_neival")) {
 936                                 /* If disabled, local node value is not
 937                                  * computed just based on terminal status
 938                                  * of the coordinate, but also its neighbors. */
 939                                 u->local_tree_neival = !optval || atoi(optval);
 940                         } else if (!strcasecmp(optname, "local_tree_eval")) {
 941                                 /* How is the value inserted in the local tree
 942                                  * determined. */
 943                                 if (!strcasecmp(optval, "root"))
 944                                         /* All moves within a tree branch are
 945                                          * considered wrt. their merit
 946                                          * reaching tachtical goal of making
 947                                          * the first move in the branch
 948                                          * survive. */
 949                                         u->local_tree_eval = LTE_ROOT;
 950                                 else if (!strcasecmp(optval, "each"))
 951                                         /* Each move is considered wrt.
 952                                          * its own survival. */
 953                                         u->local_tree_eval = LTE_EACH;
 954                                 else if (!strcasecmp(optval, "total"))
 955                                         /* The tactical goal is the survival
 956                                          * of all the moves of my color and
 957                                          * non-survival of all the opponent
 958                                          * moves. Local values (and their
 959                                          * inverses) are averaged. */
 960                                         u->local_tree_eval = LTE_TOTAL;
 961                                 else {
 962                                         fprintf(stderr, "uct: unknown local_tree_eval %s\n", optval);
 963                                         exit(1);
 964                                 }
 965                         } else if (!strcasecmp(optname, "local_tree_rootchoose")) {
 966                                 /* If disabled, only moves within the local
 967                                  * tree branch are considered; the values
 968                                  * of the branch roots (i.e. root children)
 969                                  * are ignored. This may make sense together
 970                                  * with eval!=each, we consider only moves
 971                                  * that influence the goal, not the "rating"
 972                                  * of the goal itself. (The real solution
 973                                  * will be probably using criticality to pick
 974                                  * local tree branches.) */
 975                                 u->local_tree_rootchoose = !optval || atoi(optval);
 976
 977                         /** Other heuristics */
 978                         } else if (!strcasecmp(optname, "patterns")) {
 979                                 /* Load pattern database. Various modules
 980                                  * (priors, policies etc.) may make use
 981                                  * of this database. They will request
 982                                  * it automatically in that case, but you
 983                                  * can use this option to tweak the pattern
 984                                  * parameters. */
 985                                 patterns_init(&u->pat, optval, false, true);
 986                                 u->want_pat = pat_setup = true;
 987                         } else if (!strcasecmp(optname, "significant_threshold") && optval) {
 988                                 /* Some heuristics (XXX: none in mainline) rely
 989                                  * on the knowledge of the last "significant"
 990                                  * node in the descent. Such a node is
 991                                  * considered reasonably trustworthy to carry
 992                                  * some meaningful information in the values
 993                                  * of the node and its children. */
 994                                 u->significant_threshold = atoi(optval);
 995
 996                         /** Distributed engine slaves setup */
 997
 998                         } else if (!strcasecmp(optname, "slave")) {
 999                                 /* Act as slave for the distributed engine. */
1000                                 u->slave = !optval || atoi(optval);
1001                         } else if (!strcasecmp(optname, "slave_index") && optval) {
1002                                 /* Optional index if per-slave behavior is desired.
1003                                  * Must be given as index/max */
1004                                 u->slave_index = atoi(optval);
1005                                 char *p = strchr(optval, '/');
1006                                 if (p) u->max_slaves = atoi(++p);
1007                         } else if (!strcasecmp(optname, "shared_nodes") && optval) {
1008                                 /* Share at most shared_nodes between master and slave at each genmoves.
1009                                  * Must use the same value in master and slaves. */
1010                                 u->shared_nodes = atoi(optval);
1011                         } else if (!strcasecmp(optname, "shared_levels") && optval) {
1012                                 /* Share only nodes of level <= shared_levels. */
1013                                 u->shared_levels = atoi(optval);
1014                         } else if (!strcasecmp(optname, "stats_hbits") && optval) {
1015                                 /* Set hash table size to 2^stats_hbits for the shared stats. */
1016                                 u->stats_hbits = atoi(optval);
1017                         } else if (!strcasecmp(optname, "stats_delay") && optval) {
1018                                 /* How long to wait in slave for initial stats to build up before
1019                                  * replying to the genmoves command (in ms) */
1020                                 u->stats_delay = 0.001 * atof(optval);
1021
1022                         } else {
1023                                 fprintf(stderr, "uct: Invalid engine argument %s or missing value\n", optname);
1024                                 exit(1);
1025                         }
1026                 }
1027         }
1028
1029         if (!u->policy)
1030                 u->policy = policy_ucb1amaf_init(u, NULL, b);
1031
1032         if (!!u->random_policy_chance ^ !!u->random_policy) {
1033                 fprintf(stderr, "uct: Only one of random_policy and random_policy_chance is set\n");
1034                 exit(1);
1035         }
1036
1037         if (!u->local_tree) {
1038                 /* No ltree aging. */
1039                 u->local_tree_aging = 1.0f;
1040         }
1041
1042         if (u->fast_alloc) {
1043                 if (u->pruning_threshold < u->max_tree_size / 10)
1044                         u->pruning_threshold = u->max_tree_size / 10;
1045                 if (u->pruning_threshold > u->max_tree_size / 2)
1046                         u->pruning_threshold = u->max_tree_size / 2;
1047
1048                 /* Limit pruning temp space to 20% of memory. Beyond this we discard
1049                  * the nodes and recompute them at the next move if necessary. */
1050                 u->max_pruned_size = u->max_tree_size / 5;
1051                 u->max_tree_size -= u->max_pruned_size;
1052         } else {
1053                 /* Reserve 5% memory in case the background free() are slower
1054                  * than the concurrent allocations. */
1055                 u->max_tree_size -= u->max_tree_size / 20;
1056         }
1057
1058         if (!u->prior)
1059                 u->prior = uct_prior_init(NULL, b, u);
1060
1061         if (!u->playout)
1062                 u->playout = playout_moggy_init(NULL, b, u->jdict);
1063         if (!u->playout->debug_level)
1064                 u->playout->debug_level = u->debug_level;
1065
1066         if (u->want_pat && !pat_setup)
1067                 patterns_init(&u->pat, NULL, false, true);
1068
1069         u->ownermap.map = malloc2(board_size2(b) * sizeof(u->ownermap.map[0]));
1070
1071         if (u->slave) {
1072                 if (!u->stats_hbits) u->stats_hbits = DEFAULT_STATS_HBITS;
1073                 if (!u->shared_nodes) u->shared_nodes = DEFAULT_SHARED_NODES;
1074                 assert(u->shared_levels * board_bits2(b) <= 8 * (int)sizeof(path_t));
1075         }
1076
1077         if (!u->dynkomi)
1078                 u->dynkomi = uct_dynkomi_init_linear(u, NULL, b);
1079
1080         /* Some things remain uninitialized for now - the opening tbook
1081          * is not loaded and the tree not set up. */
1082         /* This will be initialized in setup_state() at the first move
1083          * received/requested. This is because right now we are not aware
1084          * about any komi or handicap setup and such. */
1085
1086         return u;
1087 }
1088
1089 struct engine *
1090 engine_uct_init(char *arg, struct board *b)
1091 {
1092         struct uct *u = uct_state_init(arg, b);
1093         struct engine *e = calloc2(1, sizeof(struct engine));
1094         e->name = "UCT";
1095         e->printhook = uct_printhook_ownermap;
1096         e->notify_play = uct_notify_play;
1097         e->chat = uct_chat;
1098         e->undo = uct_undo;
1099         e->result = uct_result;
1100         e->genmove = uct_genmove;
1101         e->genmoves = uct_genmoves;
1102         e->evaluate = uct_evaluate;
1103         e->dead_group_list = uct_dead_group_list;
1104         e->done = uct_done;
1105         e->data = u;
1106         if (u->slave)
1107                 e->notify = uct_notify;
1108
1109         const char banner[] = "If you believe you have won but I am still playing, "
1110                 "please help me understand by capturing all dead stones. "
1111                 "Anyone can send me 'winrate' in private chat to get my assessment of the position.";
1112         if (!u->banner) u->banner = "";
1113         e->comment = malloc2(sizeof(banner) + strlen(u->banner) + 1);
1114         sprintf(e->comment, "%s %s", banner, u->banner);
1115
1116         return e;
1117 }