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->initial_extra_komi)
  46                 u->t->extra_komi = u->initial_extra_komi;
  47         if (u->force_seed)
  48                 fast_srandom(u->force_seed);
  49         if (UDEBUGL(3))
  50                 fprintf(stderr, "Fresh board with random seed %lu\n", fast_getseed());
  51         if (!u->no_tbook && b->moves == 0) {
  52                 if (color == S_BLACK) {
  53                         tree_load(u->t, b);
  54                 } else if (DEBUGL(0)) {
  55                         fprintf(stderr, "Warning: First move appears to be white\n");
  56                 }
  57         }
  58 }
  59
  60 static void
  61 reset_state(struct uct *u)
  62 {
  63         assert(u->t);
  64         tree_done(u->t); u->t = NULL;
  65 }
  66
  67 static void
  68 setup_dynkomi(struct uct *u, struct board *b, enum stone to_play)
  69 {
  70         if (u->t->use_extra_komi && !u->pondering && u->dynkomi->permove)
  71                 u->t->extra_komi = u->dynkomi->permove(u->dynkomi, b, u->t);
  72         else if (!u->t->use_extra_komi)
  73                 u->t->extra_komi = 0;
  74 }
  75
  76 void
  77 uct_prepare_move(struct uct *u, struct board *b, enum stone color)
  78 {
  79         if (u->t) {
  80                 /* Verify that we have sane state. */
  81                 assert(b->es == u);
  82                 assert(u->t && b->moves);
  83                 if (color != stone_other(u->t->root_color)) {
  84                         fprintf(stderr, "Fatal: Non-alternating play detected %d %d\n",
  85                                 color, u->t->root_color);
  86                         exit(1);
  87                 }
  88                 uct_htable_reset(u->t);
  89
  90         } else {
  91                 /* We need fresh state. */
  92                 b->es = u;
  93                 setup_state(u, b, color);
  94         }
  95
  96         u->ownermap.playouts = 0;
  97         memset(u->ownermap.map, 0, board_size2(b) * sizeof(u->ownermap.map[0]));
  98         u->played_own = u->played_all = 0;
  99 }
 100
 101 static void
 102 dead_group_list(struct uct *u, struct board *b, struct move_queue *mq)
 103 {
 104         enum gj_state gs_array[board_size2(b)];
 105         struct group_judgement gj = { .thres = GJ_THRES, .gs = gs_array };
 106         board_ownermap_judge_groups(b, &u->ownermap, &gj);
 107         groups_of_status(b, &gj, GS_DEAD, mq);
 108 }
 109
 110 bool
 111 uct_pass_is_safe(struct uct *u, struct board *b, enum stone color, bool pass_all_alive)
 112 {
 113         /* Make sure enough playouts are simulated to get a reasonable dead group list. */
 114         while (u->ownermap.playouts < GJ_MINGAMES)
 115                 uct_playout(u, b, color, u->t);
 116
 117         struct move_queue mq = { .moves = 0 };
 118         dead_group_list(u, b, &mq);
 119         if (pass_all_alive) {
 120                 for (unsigned int i = 0; i < mq.moves; i++) {
 121                         if (board_at(b, mq.move[i]) == stone_other(color)) {
 122                                 return false; // We need to remove opponent dead groups first.
 123                         }
 124                 }
 125                 mq.moves = 0; // our dead stones are alive when pass_all_alive is true
 126         }
 127         if (u->allow_losing_pass) {
 128                 foreach_point(b) {
 129                         if (board_at(b, c) == S_OFFBOARD)
 130                                 continue;
 131                         if (board_ownermap_judge_point(&u->ownermap, c, GJ_THRES) == PJ_UNKNOWN) {
 132                                 if (UDEBUGL(3))
 133                                         fprintf(stderr, "uct_pass_is_safe fails at %s[%d]\n", coord2sstr(c, b), c);
 134                                 return false; // Unclear point, clarify first.
 135                         }
 136                 } foreach_point_end;
 137                 return true;
 138         }
 139         return pass_is_safe(b, color, &mq);
 140 }
 141
 142 static char *
 143 uct_printhook_ownermap(struct board *board, coord_t c, char *s, char *end)
 144 {
 145         struct uct *u = board->es;
 146         if (!u) {
 147                 strcat(s, ". ");
 148                 return s + 2;
 149         }
 150         const char chr[] = ":XO,"; // dame, black, white, unclear
 151         const char chm[] = ":xo,";
 152         char ch = chr[board_ownermap_judge_point(&u->ownermap, c, GJ_THRES)];
 153         if (ch == ',') { // less precise estimate then?
 154                 ch = chm[board_ownermap_judge_point(&u->ownermap, c, 0.67)];
 155         }
 156         s += snprintf(s, end - s, "%c ", ch);
 157         return s;
 158 }
 159
 160 static char *
 161 uct_notify_play(struct engine *e, struct board *b, struct move *m, char *enginearg)
 162 {
 163         struct uct *u = e->data;
 164         if (!u->t) {
 165                 /* No state, create one - this is probably game beginning
 166                  * and we need to load the opening tbook right now. */
 167                 uct_prepare_move(u, b, m->color);
 168                 assert(u->t);
 169         }
 170
 171         /* Stop pondering, required by tree_promote_at() */
 172         uct_pondering_stop(u);
 173         if (UDEBUGL(2) && u->slave)
 174                 tree_dump(u->t, u->dumpthres);
 175
 176         if (is_resign(m->coord)) {
 177                 /* Reset state. */
 178                 reset_state(u);
 179                 return NULL;
 180         }
 181
 182         /* Promote node of the appropriate move to the tree root. */
 183         assert(u->t->root);
 184         if (!tree_promote_at(u->t, b, m->coord)) {
 185                 if (UDEBUGL(3))
 186                         fprintf(stderr, "Warning: Cannot promote move node! Several play commands in row?\n");
 187                 /* Preserve dynamic komi information, though, that is important. */
 188                 u->initial_extra_komi = u->t->extra_komi;
 189                 reset_state(u);
 190                 return NULL;
 191         }
 192
 193         /* If we are a slave in a distributed engine, start pondering once
 194          * we know which move we actually played. See uct_genmove() about
 195          * the check for pass. */
 196         if (u->pondering_opt && u->slave && m->color == u->my_color && !is_pass(m->coord))
 197                 uct_pondering_start(u, b, u->t, stone_other(m->color));
 198
 199         return NULL;
 200 }
 201
 202 static char *
 203 uct_undo(struct engine *e, struct board *b)
 204 {
 205         struct uct *u = e->data;
 206
 207         if (!u->t) return NULL;
 208         uct_pondering_stop(u);
 209         u->initial_extra_komi = u->t->extra_komi;
 210         reset_state(u);
 211         return NULL;
 212 }
 213
 214 static char *
 215 uct_result(struct engine *e, struct board *b)
 216 {
 217         struct uct *u = e->data;
 218         static char reply[1024];
 219
 220         if (!u->t)
 221                 return NULL;
 222         enum stone color = u->t->root_color;
 223         struct tree_node *n = u->t->root;
 224         snprintf(reply, 1024, "%s %s %d %.2f %.1f",
 225                  stone2str(color), coord2sstr(node_coord(n), b),
 226                  n->u.playouts, tree_node_get_value(u->t, -1, n->u.value),
 227                  u->t->use_extra_komi ? u->t->extra_komi : 0);
 228         return reply;
 229 }
 230
 231 static char *
 232 uct_chat(struct engine *e, struct board *b, bool opponent, char *from, char *cmd)
 233 {
 234         struct uct *u = e->data;
 235
 236         if (!u->t)
 237                 return generic_chat(b, opponent, from, cmd, S_NONE, pass, 0, 1, u->threads, 0.0, 0.0);
 238
 239         struct tree_node *n = u->t->root;
 240         double winrate = tree_node_get_value(u->t, -1, n->u.value);
 241         double extra_komi = u->t->use_extra_komi && abs(u->t->extra_komi) >= 0.5 ? u->t->extra_komi : 0;
 242
 243         return generic_chat(b, opponent, from, cmd, u->t->root_color, node_coord(n), n->u.playouts, 1,
 244                             u->threads, winrate, extra_komi);
 245 }
 246
 247 static void
 248 uct_dead_group_list(struct engine *e, struct board *b, struct move_queue *mq)
 249 {
 250         struct uct *u = e->data;
 251
 252         /* This means the game is probably over, no use pondering on. */
 253         uct_pondering_stop(u);
 254
 255         if (u->pass_all_alive)
 256                 return; // no dead groups
 257
 258         bool mock_state = false;
 259
 260         if (!u->t) {
 261                 /* No state, but we cannot just back out - we might
 262                  * have passed earlier, only assuming some stones are
 263                  * dead, and then re-connected, only to lose counting
 264                  * when all stones are assumed alive. */
 265                 uct_prepare_move(u, b, S_BLACK); assert(u->t);
 266                 mock_state = true;
 267         }
 268         /* Make sure the ownermap is well-seeded. */
 269         while (u->ownermap.playouts < GJ_MINGAMES)
 270                 uct_playout(u, b, S_BLACK, u->t);
 271         /* Show the ownermap: */
 272         if (DEBUGL(2))
 273                 board_print_custom(b, stderr, uct_printhook_ownermap);
 274
 275         dead_group_list(u, b, mq);
 276
 277         if (mock_state) {
 278                 /* Clean up the mock state in case we will receive
 279                  * a genmove; we could get a non-alternating-move
 280                  * error from uct_prepare_move() in that case otherwise. */
 281                 reset_state(u);
 282         }
 283 }
 284
 285 static void
 286 playout_policy_done(struct playout_policy *p)
 287 {
 288         if (p->done) p->done(p);
 289         if (p->data) free(p->data);
 290         free(p);
 291 }
 292
 293 static void
 294 uct_done(struct engine *e)
 295 {
 296         /* This is called on engine reset, especially when clear_board
 297          * is received and new game should begin. */
 298         struct uct *u = e->data;
 299         uct_pondering_stop(u);
 300         if (u->t) reset_state(u);
 301         free(u->ownermap.map);
 302
 303         free(u->policy);
 304         free(u->random_policy);
 305         playout_policy_done(u->playout);
 306         uct_prior_done(u->prior);
 307         joseki_done(u->jdict);
 308         pluginset_done(u->plugins);
 309 }
 310
 311
 312
 313 /* Run time-limited MCTS search on foreground. */
 314 static int
 315 uct_search(struct uct *u, struct board *b, struct time_info *ti, enum stone color, struct tree *t, bool print_progress)
 316 {
 317         struct uct_search_state s;
 318         uct_search_start(u, b, color, t, ti, &s);
 319         if (UDEBUGL(2) && s.base_playouts > 0)
 320                 fprintf(stderr, "<pre-simulated %d games>\n", s.base_playouts);
 321
 322         /* The search tree is ctx->t. This is currently == . It is important
 323          * to reference ctx->t directly since the
 324          * thread manager will swap the tree pointer asynchronously. */
 325
 326         /* Now, just periodically poll the search tree. */
 327         /* Note that in case of TD_GAMES, threads will not wait for
 328          * the uct_search_check_stop() signalization. */
 329         while (1) {
 330                 time_sleep(TREE_BUSYWAIT_INTERVAL);
 331                 /* TREE_BUSYWAIT_INTERVAL should never be less than desired time, or the
 332                  * time control is broken. But if it happens to be less, we still search
 333                  * at least 100ms otherwise the move is completely random. */
 334
 335                 int i = uct_search_games(&s);
 336                 /* Print notifications etc. */
 337                 uct_search_progress(u, b, color, t, ti, &s, i);
 338                 /* Check if we should stop the search. */
 339                 if (uct_search_check_stop(u, b, color, t, ti, &s, i))
 340                         break;
 341         }
 342
 343         struct uct_thread_ctx *ctx = uct_search_stop();
 344         if (UDEBUGL(2)) tree_dump(t, u->dumpthres);
 345         if (UDEBUGL(2))
 346                 fprintf(stderr, "(avg score %f/%d; dynkomi's %f/%d value %f/%d)\n",
 347                         t->avg_score.value, t->avg_score.playouts,
 348                         u->dynkomi->score.value, u->dynkomi->score.playouts,
 349                         u->dynkomi->value.value, u->dynkomi->value.playouts);
 350         if (print_progress)
 351                 uct_progress_status(u, t, color, ctx->games, NULL);
 352
 353         u->played_own += ctx->games;
 354         return ctx->games;
 355 }
 356
 357 /* Start pondering background with @color to play. */
 358 static void
 359 uct_pondering_start(struct uct *u, struct board *b0, struct tree *t, enum stone color)
 360 {
 361         if (UDEBUGL(1))
 362                 fprintf(stderr, "Starting to ponder with color %s\n", stone2str(stone_other(color)));
 363         u->pondering = true;
 364
 365         /* We need a local board copy to ponder upon. */
 366         struct board *b = malloc2(sizeof(*b)); board_copy(b, b0);
 367
 368         /* *b0 did not have the genmove'd move played yet. */
 369         struct move m = { node_coord(t->root), t->root_color };
 370         int res = board_play(b, &m);
 371         assert(res >= 0);
 372         setup_dynkomi(u, b, stone_other(m.color));
 373
 374         /* Start MCTS manager thread "headless". */
 375         static struct uct_search_state s;
 376         uct_search_start(u, b, color, t, NULL, &s);
 377 }
 378
 379 /* uct_search_stop() frontend for the pondering (non-genmove) mode, and
 380  * to stop the background search for a slave in the distributed engine. */
 381 void
 382 uct_pondering_stop(struct uct *u)
 383 {
 384         if (!thread_manager_running)
 385                 return;
 386
 387         /* Stop the thread manager. */
 388         struct uct_thread_ctx *ctx = uct_search_stop();
 389         if (UDEBUGL(1)) {
 390                 if (u->pondering) fprintf(stderr, "(pondering) ");
 391                 uct_progress_status(u, ctx->t, ctx->color, ctx->games, NULL);
 392         }
 393         if (u->pondering) {
 394                 free(ctx->b);
 395                 u->pondering = false;
 396         }
 397 }
 398
 399
 400 void
 401 uct_genmove_setup(struct uct *u, struct board *b, enum stone color)
 402 {
 403         if (b->superko_violation) {
 404                 fprintf(stderr, "!!! WARNING: SUPERKO VIOLATION OCCURED BEFORE THIS MOVE\n");
 405                 fprintf(stderr, "Maybe you play with situational instead of positional superko?\n");
 406                 fprintf(stderr, "I'm going to ignore the violation, but note that I may miss\n");
 407                 fprintf(stderr, "some moves valid under this ruleset because of this.\n");
 408                 b->superko_violation = false;
 409         }
 410
 411         uct_prepare_move(u, b, color);
 412
 413         assert(u->t);
 414         u->my_color = color;
 415
 416         /* How to decide whether to use dynkomi in this game? Since we use
 417          * pondering, it's not simple "who-to-play" matter. Decide based on
 418          * the last genmove issued. */
 419         u->t->use_extra_komi = !!(u->dynkomi_mask & color);
 420         setup_dynkomi(u, b, color);
 421
 422         if (b->rules == RULES_JAPANESE)
 423                 u->territory_scoring = true;
 424
 425         /* Make pessimistic assumption about komi for Japanese rules to
 426          * avoid losing by 0.5 when winning by 0.5 with Chinese rules.
 427          * The rules usually give the same winner if the integer part of komi
 428          * is odd so we adjust the komi only if it is even (for a board of
 429          * odd size). We are not trying  to get an exact evaluation for rare
 430          * cases of seki. For details see http://home.snafu.de/jasiek/parity.html */
 431         if (u->territory_scoring && (((int)floor(b->komi) + board_size(b)) & 1)) {
 432                 b->komi += (color == S_BLACK ? 1.0 : -1.0);
 433                 if (UDEBUGL(0))
 434                         fprintf(stderr, "Setting komi to %.1f assuming Japanese rules\n",
 435                                 b->komi);
 436         }
 437 }
 438
 439 static coord_t *
 440 uct_genmove(struct engine *e, struct board *b, struct time_info *ti, enum stone color, bool pass_all_alive)
 441 {
 442         double start_time = time_now();
 443         struct uct *u = e->data;
 444         u->pass_all_alive |= pass_all_alive;
 445         uct_pondering_stop(u);
 446         uct_genmove_setup(u, b, color);
 447
 448         /* Start the Monte Carlo Tree Search! */
 449         int base_playouts = u->t->root->u.playouts;
 450         int played_games = uct_search(u, b, ti, color, u->t, false);
 451
 452         coord_t best_coord;
 453         struct tree_node *best;
 454         best = uct_search_result(u, b, color, u->pass_all_alive, played_games, base_playouts, &best_coord);
 455
 456         if (UDEBUGL(2)) {
 457                 double time = time_now() - start_time + 0.000001; /* avoid divide by zero */
 458                 fprintf(stderr, "genmove in %0.2fs (%d games/s, %d games/s/thread)\n",
 459                         time, (int)(played_games/time), (int)(played_games/time/u->threads));
 460         }
 461
 462         uct_progress_status(u, u->t, color, played_games, &best_coord);
 463
 464         if (!best) {
 465                 /* Pass or resign. */
 466                 if (is_pass(best_coord))
 467                         u->initial_extra_komi = u->t->extra_komi;
 468                 reset_state(u);
 469                 return coord_copy(best_coord);
 470         }
 471         tree_promote_node(u->t, &best);
 472
 473         /* After a pass, pondering is harmful for two reasons:
 474          * (i) We might keep pondering even when the game is over.
 475          * Of course this is the case for opponent resign as well.
 476          * (ii) More importantly, the ownermap will get skewed since
 477          * the UCT will start cutting off any playouts. */
 478         if (u->pondering_opt && !is_pass(node_coord(best))) {
 479                 uct_pondering_start(u, b, u->t, stone_other(color));
 480         }
 481         return coord_copy(best_coord);
 482 }
 483
 484
 485 bool
 486 uct_gentbook(struct engine *e, struct board *b, struct time_info *ti, enum stone color)
 487 {
 488         struct uct *u = e->data;
 489         if (!u->t) uct_prepare_move(u, b, color);
 490         assert(u->t);
 491
 492         if (ti->dim == TD_GAMES) {
 493                 /* Don't count in games that already went into the tbook. */
 494                 ti->len.games += u->t->root->u.playouts;
 495         }
 496         uct_search(u, b, ti, color, u->t, true);
 497
 498         assert(ti->dim == TD_GAMES);
 499         tree_save(u->t, b, ti->len.games / 100);
 500
 501         return true;
 502 }
 503
 504 void
 505 uct_dumptbook(struct engine *e, struct board *b, enum stone color)
 506 {
 507         struct uct *u = e->data;
 508         struct tree *t = tree_init(b, color, u->fast_alloc ? u->max_tree_size : 0,
 509                          u->max_pruned_size, u->pruning_threshold, u->local_tree_aging, 0);
 510         tree_load(t, b);
 511         tree_dump(t, 0);
 512         tree_done(t);
 513 }
 514
 515
 516 floating_t
 517 uct_evaluate_one(struct engine *e, struct board *b, struct time_info *ti, coord_t c, enum stone color)
 518 {
 519         struct uct *u = e->data;
 520
 521         struct board b2;
 522         board_copy(&b2, b);
 523         struct move m = { c, color };
 524         int res = board_play(&b2, &m);
 525         if (res < 0)
 526                 return NAN;
 527         color = stone_other(color);
 528
 529         if (u->t) reset_state(u);
 530         uct_prepare_move(u, &b2, color);
 531         assert(u->t);
 532
 533         floating_t bestval;
 534         uct_search(u, &b2, ti, color, u->t, true);
 535         struct tree_node *best = u->policy->choose(u->policy, u->t->root, &b2, color, resign);
 536         if (!best) {
 537                 bestval = NAN; // the opponent has no reply!
 538         } else {
 539                 bestval = tree_node_get_value(u->t, 1, best->u.value);
 540         }
 541
 542         reset_state(u); // clean our junk
 543
 544         return isnan(bestval) ? NAN : 1.0f - bestval;
 545 }
 546
 547 void
 548 uct_evaluate(struct engine *e, struct board *b, struct time_info *ti, floating_t *vals, enum stone color)
 549 {
 550         for (int i = 0; i < b->flen; i++) {
 551                 if (is_pass(b->f[i]))
 552                         vals[i] = NAN;
 553                 else
 554                         vals[i] = uct_evaluate_one(e, b, ti, b->f[i], color);
 555         }
 556 }
 557
 558
 559 struct uct *
 560 uct_state_init(char *arg, struct board *b)
 561 {
 562         struct uct *u = calloc2(1, sizeof(struct uct));
 563         bool pat_setup = false;
 564
 565         u->debug_level = debug_level;
 566         u->reportfreq = 10000;
 567         u->gamelen = MC_GAMELEN;
 568         u->resign_threshold = 0.2;
 569         u->sure_win_threshold = 0.9;
 570         u->mercymin = 0;
 571         u->significant_threshold = 50;
 572         u->expand_p = 8;
 573         u->dumpthres = 1000;
 574         u->playout_amaf = true;
 575         u->amaf_prior = false;
 576         u->max_tree_size = 1408ULL * 1048576;
 577         u->fast_alloc = true;
 578         u->pruning_threshold = 0;
 579
 580         u->threads = 1;
 581         u->thread_model = TM_TREEVL;
 582         u->virtual_loss = 1;
 583
 584         u->fuseki_end = 20; // max time at 361*20% = 72 moves (our 36th move, still 99 to play)
 585         u->yose_start = 40; // (100-40-25)*361/100/2 = 63 moves still to play by us then
 586         u->bestr_ratio = 0.02;
 587         // 2.5 is clearly too much, but seems to compensate well for overly stern time allocations.
 588         // TODO: Further tuning and experiments with better time allocation schemes.
 589         u->best2_ratio = 2.5;
 590         u->max_maintime_ratio = 3.0;
 591
 592         u->val_scale = 0; u->val_points = 40;
 593         u->dynkomi_interval = 1000;
 594         u->dynkomi_mask = S_BLACK | S_WHITE;
 595
 596         u->tenuki_d = 4;
 597         u->local_tree_aging = 80;
 598         u->local_tree_depth_decay = 1.5;
 599         u->local_tree_eval = LTE_ROOT;
 600         u->local_tree_neival = true;
 601
 602         u->max_slaves = -1;
 603         u->slave_index = -1;
 604         u->stats_delay = 0.01; // 10 ms
 605
 606         u->plugins = pluginset_init(b);
 607
 608         u->jdict = joseki_load(b->size);
 609
 610         if (arg) {
 611                 char *optspec, *next = arg;
 612                 while (*next) {
 613                         optspec = next;
 614                         next += strcspn(next, ",");
 615                         if (*next) { *next++ = 0; } else { *next = 0; }
 616
 617                         char *optname = optspec;
 618                         char *optval = strchr(optspec, '=');
 619                         if (optval) *optval++ = 0;
 620
 621                         /** Basic options */
 622
 623                         if (!strcasecmp(optname, "debug")) {
 624                                 if (optval)
 625                                         u->debug_level = atoi(optval);
 626                                 else
 627                                         u->debug_level++;
 628                         } else if (!strcasecmp(optname, "reporting") && optval) {
 629                                 /* The format of output for detailed progress
 630                                  * information (such as current best move and
 631                                  * its value, etc.). */
 632                                 if (!strcasecmp(optval, "text")) {
 633                                         /* Plaintext traditional output. */
 634                                         u->reporting = UR_TEXT;
 635                                 } else if (!strcasecmp(optval, "json")) {
 636                                         /* JSON output. Implies debug=0. */
 637                                         u->reporting = UR_JSON;
 638                                         u->debug_level = 0;
 639                                 } else if (!strcasecmp(optval, "jsonbig")) {
 640                                         /* JSON output, but much more detailed.
 641                                          * Implies debug=0. */
 642                                         u->reporting = UR_JSON_BIG;
 643                                         u->debug_level = 0;
 644                                 } else {
 645                                         fprintf(stderr, "UCT: Invalid reporting format %s\n", optval);
 646                                         exit(1);
 647                                 }
 648                         } else if (!strcasecmp(optname, "reportfreq") && optval) {
 649                                 /* The progress information line will be shown
 650                                  * every <reportfreq> simulations. */
 651                                 u->reportfreq = atoi(optval);
 652                         } else if (!strcasecmp(optname, "dumpthres") && optval) {
 653                                 /* When dumping the UCT tree on output, include
 654                                  * nodes with at least this many playouts.
 655                                  * (This value is re-scaled "intelligently"
 656                                  * in case of very large trees.) */
 657                                 u->dumpthres = atoi(optval);
 658                         } else if (!strcasecmp(optname, "resign_threshold") && optval) {
 659                                 /* Resign when this ratio of games is lost
 660                                  * after GJ_MINGAMES sample is taken. */
 661                                 u->resign_threshold = atof(optval);
 662                         } else if (!strcasecmp(optname, "sure_win_threshold") && optval) {
 663                                 /* Stop reading when this ratio of games is won
 664                                  * after PLAYOUT_EARLY_BREAK_MIN sample is
 665                                  * taken. (Prevents stupid time losses,
 666                                  * friendly to human opponents.) */
 667                                 u->sure_win_threshold = atof(optval);
 668                         } else if (!strcasecmp(optname, "force_seed") && optval) {
 669                                 /* Set RNG seed at the tree setup. */
 670                                 u->force_seed = atoi(optval);
 671                         } else if (!strcasecmp(optname, "no_tbook")) {
 672                                 /* Disable UCT opening tbook. */
 673                                 u->no_tbook = true;
 674                         } else if (!strcasecmp(optname, "pass_all_alive")) {
 675                                 /* Whether to consider passing only after all
 676                                  * dead groups were removed from the board;
 677                                  * this is like all genmoves are in fact
 678                                  * kgs-genmove_cleanup. */
 679                                 u->pass_all_alive = !optval || atoi(optval);
 680                         } else if (!strcasecmp(optname, "allow_losing_pass")) {
 681                                 /* Whether to consider passing in a clear
 682                                  * but losing situation, to be scored as a loss
 683                                  * for us. */
 684                                 u->allow_losing_pass = !optval || atoi(optval);
 685                         } else if (!strcasecmp(optname, "territory_scoring")) {
 686                                 /* Use territory scoring (default is area scoring).
 687                                  * An explicit kgs-rules command overrides this. */
 688                                 u->territory_scoring = !optval || atoi(optval);
 689                         } else if (!strcasecmp(optname, "stones_only")) {
 690                                 /* Do not count eyes. Nice to teach go to kids.
 691                                  * http://strasbourg.jeudego.org/regle_strasbourgeoise.htm */
 692                                 b->rules = RULES_STONES_ONLY;
 693                                 u->pass_all_alive = true;
 694                         } else if (!strcasecmp(optname, "banner") && optval) {
 695                                 /* Additional banner string. This must come as the
 696                                  * last engine parameter. */
 697                                 if (*next) *--next = ',';
 698                                 u->banner = strdup(optval);
 699                                 break;
 700                         } else if (!strcasecmp(optname, "plugin") && optval) {
 701                                 /* Load an external plugin; filename goes before the colon,
 702                                  * extra arguments after the colon. */
 703                                 char *pluginarg = strchr(optval, ':');
 704                                 if (pluginarg)
 705                                         *pluginarg++ = 0;
 706                                 plugin_load(u->plugins, optval, pluginarg);
 707
 708                         /** UCT behavior and policies */
 709
 710                         } else if ((!strcasecmp(optname, "policy")
 711                                 /* Node selection policy. ucb1amaf is the
 712                                  * default policy implementing RAVE, while
 713                                  * ucb1 is the simple exploration/exploitation
 714                                  * policy. Policies can take further extra
 715                                  * options. */
 716                                     || !strcasecmp(optname, "random_policy")) && optval) {
 717                                 /* A policy to be used randomly with small
 718                                  * chance instead of the default policy. */
 719                                 char *policyarg = strchr(optval, ':');
 720                                 struct uct_policy **p = !strcasecmp(optname, "policy") ? &u->policy : &u->random_policy;
 721                                 if (policyarg)
 722                                         *policyarg++ = 0;
 723                                 if (!strcasecmp(optval, "ucb1")) {
 724                                         *p = policy_ucb1_init(u, policyarg);
 725                                 } else if (!strcasecmp(optval, "ucb1amaf")) {
 726                                         *p = policy_ucb1amaf_init(u, policyarg, b);
 727                                 } else {
 728                                         fprintf(stderr, "UCT: Invalid tree policy %s\n", optval);
 729                                         exit(1);
 730                                 }
 731                         } else if (!strcasecmp(optname, "playout") && optval) {
 732                                 /* Random simulation (playout) policy.
 733                                  * moggy is the default policy with large
 734                                  * amount of domain-specific knowledge and
 735                                  * heuristics. light is a simple uniformly
 736                                  * random move selection policy. */
 737                                 char *playoutarg = strchr(optval, ':');
 738                                 if (playoutarg)
 739                                         *playoutarg++ = 0;
 740                                 if (!strcasecmp(optval, "moggy")) {
 741                                         u->playout = playout_moggy_init(playoutarg, b, u->jdict);
 742                                 } else if (!strcasecmp(optval, "light")) {
 743                                         u->playout = playout_light_init(playoutarg, b);
 744                                 } else {
 745                                         fprintf(stderr, "UCT: Invalid playout policy %s\n", optval);
 746                                         exit(1);
 747                                 }
 748                         } else if (!strcasecmp(optname, "prior") && optval) {
 749                                 /* Node priors policy. When expanding a node,
 750                                  * it will seed node values heuristically
 751                                  * (most importantly, based on playout policy
 752                                  * opinion, but also with regard to other
 753                                  * things). See uct/prior.c for details.
 754                                  * Use prior=eqex=0 to disable priors. */
 755                                 u->prior = uct_prior_init(optval, b, u);
 756                         } else if (!strcasecmp(optname, "mercy") && optval) {
 757                                 /* Minimal difference of black/white captures
 758                                  * to stop playout - "Mercy Rule". Speeds up
 759                                  * hopeless playouts at the expense of some
 760                                  * accuracy. */
 761                                 u->mercymin = atoi(optval);
 762                         } else if (!strcasecmp(optname, "gamelen") && optval) {
 763                                 /* Maximum length of single simulation
 764                                  * in moves. */
 765                                 u->gamelen = atoi(optval);
 766                         } else if (!strcasecmp(optname, "expand_p") && optval) {
 767                                 /* Expand UCT nodes after it has been
 768                                  * visited this many times. */
 769                                 u->expand_p = atoi(optval);
 770                         } else if (!strcasecmp(optname, "random_policy_chance") && optval) {
 771                                 /* If specified (N), with probability 1/N, random_policy policy
 772                                  * descend is used instead of main policy descend; useful
 773                                  * if specified policy (e.g. UCB1AMAF) can make unduly biased
 774                                  * choices sometimes, you can fall back to e.g.
 775                                  * random_policy=UCB1. */
 776                                 u->random_policy_chance = atoi(optval);
 777
 778                         /** General AMAF behavior */
 779                         /* (Only relevant if the policy supports AMAF.
 780                          * More variables can be tuned as policy
 781                          * parameters.) */
 782
 783                         } else if (!strcasecmp(optname, "playout_amaf")) {
 784                                 /* Whether to include random playout moves in
 785                                  * AMAF as well. (Otherwise, only tree moves
 786                                  * are included in AMAF. Of course makes sense
 787                                  * only in connection with an AMAF policy.) */
 788                                 /* with-without: 55.5% (+-4.1) */
 789                                 if (optval && *optval == '0')
 790                                         u->playout_amaf = false;
 791                                 else
 792                                         u->playout_amaf = true;
 793                         } else if (!strcasecmp(optname, "playout_amaf_cutoff") && optval) {
 794                                 /* Keep only first N% of playout stage AMAF
 795                                  * information. */
 796                                 u->playout_amaf_cutoff = atoi(optval);
 797                         } else if (!strcasecmp(optname, "amaf_prior") && optval) {
 798                                 /* In node policy, consider prior values
 799                                  * part of the real result term or part
 800                                  * of the AMAF term? */
 801                                 u->amaf_prior = atoi(optval);
 802
 803                         /** Performance and memory management */
 804
 805                         } else if (!strcasecmp(optname, "threads") && optval) {
 806                                 /* By default, Pachi will run with only single
 807                                  * tree search thread! */
 808                                 u->threads = atoi(optval);
 809                         } else if (!strcasecmp(optname, "thread_model") && optval) {
 810                                 if (!strcasecmp(optval, "tree")) {
 811                                         /* Tree parallelization - all threads
 812                                          * grind on the same tree. */
 813                                         u->thread_model = TM_TREE;
 814                                         u->virtual_loss = 0;
 815                                 } else if (!strcasecmp(optval, "treevl")) {
 816                                         /* Tree parallelization, but also
 817                                          * with virtual losses - this discou-
 818                                          * rages most threads choosing the
 819                                          * same tree branches to read. */
 820                                         u->thread_model = TM_TREEVL;
 821                                 } else {
 822                                         fprintf(stderr, "UCT: Invalid thread model %s\n", optval);
 823                                         exit(1);
 824                                 }
 825                         } else if (!strcasecmp(optname, "virtual_loss")) {
 826                                 /* Number of virtual losses added before evaluating a node. */
 827                                 u->virtual_loss = !optval || atoi(optval);
 828                         } else if (!strcasecmp(optname, "pondering")) {
 829                                 /* Keep searching even during opponent's turn. */
 830                                 u->pondering_opt = !optval || atoi(optval);
 831                         } else if (!strcasecmp(optname, "max_tree_size") && optval) {
 832                                 /* Maximum amount of memory [MiB] consumed by the move tree.
 833                                  * For fast_alloc it includes the temp tree used for pruning.
 834                                  * Default is 3072 (3 GiB). */
 835                                 u->max_tree_size = atol(optval) * 1048576;
 836                         } else if (!strcasecmp(optname, "fast_alloc")) {
 837                                 u->fast_alloc = !optval || atoi(optval);
 838                         } else if (!strcasecmp(optname, "pruning_threshold") && optval) {
 839                                 /* Force pruning at beginning of a move if the tree consumes
 840                                  * more than this [MiB]. Default is 10% of max_tree_size.
 841                                  * Increase to reduce pruning time overhead if memory is plentiful.
 842                                  * This option is meaningful only for fast_alloc. */
 843                                 u->pruning_threshold = atol(optval) * 1048576;
 844
 845                         /** Time control */
 846
 847                         } else if (!strcasecmp(optname, "best2_ratio") && optval) {
 848                                 /* If set, prolong simulating while
 849                                  * first_best/second_best playouts ratio
 850                                  * is less than best2_ratio. */
 851                                 u->best2_ratio = atof(optval);
 852                         } else if (!strcasecmp(optname, "bestr_ratio") && optval) {
 853                                 /* If set, prolong simulating while
 854                                  * best,best_best_child values delta
 855                                  * is more than bestr_ratio. */
 856                                 u->bestr_ratio = atof(optval);
 857                         } else if (!strcasecmp(optname, "max_maintime_ratio") && optval) {
 858                                 /* If set and while not in byoyomi, prolong simulating no more than
 859                                  * max_maintime_ratio times the normal desired thinking time. */
 860                                 u->max_maintime_ratio = atof(optval);
 861                         } else if (!strcasecmp(optname, "fuseki_end") && optval) {
 862                                 /* At the very beginning it's not worth thinking
 863                                  * too long because the playout evaluations are
 864                                  * very noisy. So gradually increase the thinking
 865                                  * time up to maximum when fuseki_end percent
 866                                  * of the board has been played.
 867                                  * This only applies if we are not in byoyomi. */
 868                                 u->fuseki_end = atoi(optval);
 869                         } else if (!strcasecmp(optname, "yose_start") && optval) {
 870                                 /* When yose_start percent of the board has been
 871                                  * played, or if we are in byoyomi, stop spending
 872                                  * more time and spread the remaining time
 873                                  * uniformly.
 874                                  * Between fuseki_end and yose_start, we spend
 875                                  * a constant proportion of the remaining time
 876                                  * on each move. (yose_start should actually
 877                                  * be much earlier than when real yose start,
 878                                  * but "yose" is a good short name to convey
 879                                  * the idea.) */
 880                                 u->yose_start = atoi(optval);
 881
 882                         /** Dynamic komi */
 883
 884                         } else if (!strcasecmp(optname, "dynkomi") && optval) {
 885                                 /* Dynamic komi approach; there are multiple
 886                                  * ways to adjust komi dynamically throughout
 887                                  * play. We currently support two: */
 888                                 char *dynkomiarg = strchr(optval, ':');
 889                                 if (dynkomiarg)
 890                                         *dynkomiarg++ = 0;
 891                                 if (!strcasecmp(optval, "none")) {
 892                                         u->dynkomi = uct_dynkomi_init_none(u, dynkomiarg, b);
 893                                 } else if (!strcasecmp(optval, "linear")) {
 894                                         /* You should set dynkomi_mask=1 or a very low
 895                                          * handicap_value for white. */
 896                                         u->dynkomi = uct_dynkomi_init_linear(u, dynkomiarg, b);
 897                                 } else if (!strcasecmp(optval, "adaptive")) {
 898                                         /* There are many more knobs to
 899                                          * crank - see uct/dynkomi.c. */
 900                                         u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomiarg, b);
 901                                 } else {
 902                                         fprintf(stderr, "UCT: Invalid dynkomi mode %s\n", optval);
 903                                         exit(1);
 904                                 }
 905                         } else if (!strcasecmp(optname, "dynkomi_mask") && optval) {
 906                                 /* Bitmask of colors the player must be
 907                                  * for dynkomi be applied; the default dynkomi_mask=3 allows
 908                                  * dynkomi even in games where Pachi is white. */
 909                                 u->dynkomi_mask = atoi(optval);
 910                         } else if (!strcasecmp(optname, "dynkomi_interval") && optval) {
 911                                 /* If non-zero, re-adjust dynamic komi
 912                                  * throughout a single genmove reading,
 913                                  * roughly every N simulations. */
 914                                 /* XXX: Does not work with tree
 915                                  * parallelization. */
 916                                 u->dynkomi_interval = atoi(optval);
 917                         } else if (!strcasecmp(optname, "extra_komi") && optval) {
 918                                 /* Initial dynamic komi settings. This
 919                                  * is useful for the adaptive dynkomi
 920                                  * policy as the value to start with
 921                                  * (this is NOT kept fixed) in case
 922                                  * there is not enough time in the search
 923                                  * to adjust the value properly (e.g. the
 924                                  * game was interrupted). */
 925                                 u->initial_extra_komi = atof(optval);
 926
 927                         /** Node value result scaling */
 928
 929                         } else if (!strcasecmp(optname, "val_scale") && optval) {
 930                                 /* How much of the game result value should be
 931                                  * influenced by win size. Zero means it isn't. */
 932                                 u->val_scale = atof(optval);
 933                         } else if (!strcasecmp(optname, "val_points") && optval) {
 934                                 /* Maximum size of win to be scaled into game
 935                                  * result value. Zero means boardsize^2. */
 936                                 u->val_points = atoi(optval) * 2; // result values are doubled
 937                         } else if (!strcasecmp(optname, "val_extra")) {
 938                                 /* If false, the score coefficient will be simply
 939                                  * added to the value, instead of scaling the result
 940                                  * coefficient because of it. */
 941                                 u->val_extra = !optval || atoi(optval);
 942                         } else if (!strcasecmp(optname, "val_byavg")) {
 943                                 /* If true, the score included in the value will
 944                                  * be relative to average score in the current
 945                                  * search episode inst. of jigo. */
 946                                 u->val_byavg = !optval || atoi(optval);
 947                         } else if (!strcasecmp(optname, "val_bytemp")) {
 948                                 /* If true, the value scaling coefficient
 949                                  * is different based on value extremity
 950                                  * (dist. from 0.5), linear between
 951                                  * val_bytemp_min, val_scale. */
 952                                 u->val_bytemp = !optval || atoi(optval);
 953                         } else if (!strcasecmp(optname, "val_bytemp_min") && optval) {
 954                                 /* Minimum val_scale in case of val_bytemp. */
 955                                 u->val_bytemp_min = atof(optval);
 956
 957                         /** Local trees */
 958                         /* (Purely experimental. Does not work - yet!) */
 959
 960                         } else if (!strcasecmp(optname, "local_tree")) {
 961                                 /* Whether to bias exploration by local tree values. */
 962                                 u->local_tree = !optval || atoi(optval);
 963                         } else if (!strcasecmp(optname, "tenuki_d") && optval) {
 964                                 /* Tenuki distance at which to break the local tree. */
 965                                 u->tenuki_d = atoi(optval);
 966                                 if (u->tenuki_d > TREE_NODE_D_MAX + 1) {
 967                                         fprintf(stderr, "uct: tenuki_d must not be larger than TREE_NODE_D_MAX+1 %d\n", TREE_NODE_D_MAX + 1);
 968                                         exit(1);
 969                                 }
 970                         } else if (!strcasecmp(optname, "local_tree_aging") && optval) {
 971                                 /* How much to reduce local tree values between moves. */
 972                                 u->local_tree_aging = atof(optval);
 973                         } else if (!strcasecmp(optname, "local_tree_depth_decay") && optval) {
 974                                 /* With value x>0, during the descent the node
 975                                  * contributes 1/x^depth playouts in
 976                                  * the local tree. I.e., with x>1, nodes more
 977                                  * distant from local situation contribute more
 978                                  * than nodes near the root. */
 979                                 u->local_tree_depth_decay = atof(optval);
 980                         } else if (!strcasecmp(optname, "local_tree_allseq")) {
 981                                 /* If disabled, only complete sequences are stored
 982                                  * in the local tree. If this is on, also
 983                                  * subsequences starting at each move are stored. */
 984                                 u->local_tree_allseq = !optval || atoi(optval);
 985                         } else if (!strcasecmp(optname, "local_tree_neival")) {
 986                                 /* If disabled, local node value is not
 987                                  * computed just based on terminal status
 988                                  * of the coordinate, but also its neighbors. */
 989                                 u->local_tree_neival = !optval || atoi(optval);
 990                         } else if (!strcasecmp(optname, "local_tree_eval")) {
 991                                 /* How is the value inserted in the local tree
 992                                  * determined. */
 993                                 if (!strcasecmp(optval, "root"))
 994                                         /* All moves within a tree branch are
 995                                          * considered wrt. their merit
 996                                          * reaching tachtical goal of making
 997                                          * the first move in the branch
 998                                          * survive. */
 999                                         u->local_tree_eval = LTE_ROOT;
1000                                 else if (!strcasecmp(optval, "each"))
1001                                         /* Each move is considered wrt.
1002                                          * its own survival. */
1003                                         u->local_tree_eval = LTE_EACH;
1004                                 else if (!strcasecmp(optval, "total"))
1005                                         /* The tactical goal is the survival
1006                                          * of all the moves of my color and
1007                                          * non-survival of all the opponent
1008                                          * moves. Local values (and their
1009                                          * inverses) are averaged. */
1010                                         u->local_tree_eval = LTE_TOTAL;
1011                                 else {
1012                                         fprintf(stderr, "uct: unknown local_tree_eval %s\n", optval);
1013                                         exit(1);
1014                                 }
1015                         } else if (!strcasecmp(optname, "local_tree_rootchoose")) {
1016                                 /* If disabled, only moves within the local
1017                                  * tree branch are considered; the values
1018                                  * of the branch roots (i.e. root children)
1019                                  * are ignored. This may make sense together
1020                                  * with eval!=each, we consider only moves
1021                                  * that influence the goal, not the "rating"
1022                                  * of the goal itself. (The real solution
1023                                  * will be probably using criticality to pick
1024                                  * local tree branches.) */
1025                                 u->local_tree_rootchoose = !optval || atoi(optval);
1026
1027                         /** Other heuristics */
1028                         } else if (!strcasecmp(optname, "patterns")) {
1029                                 /* Load pattern database. Various modules
1030                                  * (priors, policies etc.) may make use
1031                                  * of this database. They will request
1032                                  * it automatically in that case, but you
1033                                  * can use this option to tweak the pattern
1034                                  * parameters. */
1035                                 patterns_init(&u->pat, optval, false, true);
1036                                 u->want_pat = pat_setup = true;
1037                         } else if (!strcasecmp(optname, "significant_threshold") && optval) {
1038                                 /* Some heuristics (XXX: none in mainline) rely
1039                                  * on the knowledge of the last "significant"
1040                                  * node in the descent. Such a node is
1041                                  * considered reasonably trustworthy to carry
1042                                  * some meaningful information in the values
1043                                  * of the node and its children. */
1044                                 u->significant_threshold = atoi(optval);
1045
1046                         /** Distributed engine slaves setup */
1047
1048                         } else if (!strcasecmp(optname, "slave")) {
1049                                 /* Act as slave for the distributed engine. */
1050                                 u->slave = !optval || atoi(optval);
1051                         } else if (!strcasecmp(optname, "slave_index") && optval) {
1052                                 /* Optional index if per-slave behavior is desired.
1053                                  * Must be given as index/max */
1054                                 u->slave_index = atoi(optval);
1055                                 char *p = strchr(optval, '/');
1056                                 if (p) u->max_slaves = atoi(++p);
1057                         } else if (!strcasecmp(optname, "shared_nodes") && optval) {
1058                                 /* Share at most shared_nodes between master and slave at each genmoves.
1059                                  * Must use the same value in master and slaves. */
1060                                 u->shared_nodes = atoi(optval);
1061                         } else if (!strcasecmp(optname, "shared_levels") && optval) {
1062                                 /* Share only nodes of level <= shared_levels. */
1063                                 u->shared_levels = atoi(optval);
1064                         } else if (!strcasecmp(optname, "stats_hbits") && optval) {
1065                                 /* Set hash table size to 2^stats_hbits for the shared stats. */
1066                                 u->stats_hbits = atoi(optval);
1067                         } else if (!strcasecmp(optname, "stats_delay") && optval) {
1068                                 /* How long to wait in slave for initial stats to build up before
1069                                  * replying to the genmoves command (in ms) */
1070                                 u->stats_delay = 0.001 * atof(optval);
1071
1072                         /** Presets */
1073
1074                         } else if (!strcasecmp(optname, "maximize_score")) {
1075                                 /* A combination of settings that will make
1076                                  * Pachi try to maximize his points (instead
1077                                  * of playing slack yose) or minimize his loss
1078                                  * (and proceed to counting even when losing). */
1079                                 /* Please note that this preset might be
1080                                  * somewhat weaker than normal Pachi, and the
1081                                  * score maximization is approximate; point size
1082                                  * of win/loss still should not be used to judge
1083                                  * strength of Pachi or the opponent. */
1084                                 /* See README for some further notes. */
1085                                 if (!optval || atoi(optval)) {
1086                                         /* Allow scoring a lost game. */
1087                                         u->allow_losing_pass = true;
1088                                         /* Make Pachi keep his calm when losing
1089                                          * and/or maintain winning marging. */
1090                                         /* Do not play games that are losing
1091                                          * by too much. */
1092                                         /* XXX: komi_ratchet_age=40000 is necessary
1093                                          * with losing_komi_ratchet, but 40000
1094                                          * is somewhat arbitrary value. */
1095                                         char dynkomi_args[] = "losing_komi_ratchet:komi_ratchet_age=60000:no_komi_at_game_end=0:max_losing_komi=30";
1096                                         u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomi_args, b);
1097                                         /* XXX: Values arbitrary so far. */
1098                                         /* XXX: Also, is bytemp sensible when
1099                                          * combined with dynamic komi?! */
1100                                         u->val_scale = 0.01;
1101                                         u->val_bytemp = true;
1102                                         u->val_bytemp_min = 0.001;
1103                                         u->val_byavg = true;
1104                                 }
1105
1106                         } else {
1107                                 fprintf(stderr, "uct: Invalid engine argument %s or missing value\n", optname);
1108                                 exit(1);
1109                         }
1110                 }
1111         }
1112
1113         if (!u->policy)
1114                 u->policy = policy_ucb1amaf_init(u, NULL, b);
1115
1116         if (!!u->random_policy_chance ^ !!u->random_policy) {
1117                 fprintf(stderr, "uct: Only one of random_policy and random_policy_chance is set\n");
1118                 exit(1);
1119         }
1120
1121         if (!u->local_tree) {
1122                 /* No ltree aging. */
1123                 u->local_tree_aging = 1.0f;
1124         }
1125
1126         if (u->fast_alloc) {
1127                 if (u->pruning_threshold < u->max_tree_size / 10)
1128                         u->pruning_threshold = u->max_tree_size / 10;
1129                 if (u->pruning_threshold > u->max_tree_size / 2)
1130                         u->pruning_threshold = u->max_tree_size / 2;
1131
1132                 /* Limit pruning temp space to 20% of memory. Beyond this we discard
1133                  * the nodes and recompute them at the next move if necessary. */
1134                 u->max_pruned_size = u->max_tree_size / 5;
1135                 u->max_tree_size -= u->max_pruned_size;
1136         } else {
1137                 /* Reserve 5% memory in case the background free() are slower
1138                  * than the concurrent allocations. */
1139                 u->max_tree_size -= u->max_tree_size / 20;
1140         }
1141
1142         if (!u->prior)
1143                 u->prior = uct_prior_init(NULL, b, u);
1144
1145         if (!u->playout)
1146                 u->playout = playout_moggy_init(NULL, b, u->jdict);
1147         if (!u->playout->debug_level)
1148                 u->playout->debug_level = u->debug_level;
1149
1150         if (u->want_pat && !pat_setup)
1151                 patterns_init(&u->pat, NULL, false, true);
1152
1153         u->ownermap.map = malloc2(board_size2(b) * sizeof(u->ownermap.map[0]));
1154
1155         if (u->slave) {
1156                 if (!u->stats_hbits) u->stats_hbits = DEFAULT_STATS_HBITS;
1157                 if (!u->shared_nodes) u->shared_nodes = DEFAULT_SHARED_NODES;
1158                 assert(u->shared_levels * board_bits2(b) <= 8 * (int)sizeof(path_t));
1159         }
1160
1161         if (!u->dynkomi)
1162                 u->dynkomi = uct_dynkomi_init_linear(u, NULL, b);
1163
1164         /* Some things remain uninitialized for now - the opening tbook
1165          * is not loaded and the tree not set up. */
1166         /* This will be initialized in setup_state() at the first move
1167          * received/requested. This is because right now we are not aware
1168          * about any komi or handicap setup and such. */
1169
1170         return u;
1171 }
1172
1173 struct engine *
1174 engine_uct_init(char *arg, struct board *b)
1175 {
1176         struct uct *u = uct_state_init(arg, b);
1177         struct engine *e = calloc2(1, sizeof(struct engine));
1178         e->name = "UCT";
1179         e->printhook = uct_printhook_ownermap;
1180         e->notify_play = uct_notify_play;
1181         e->chat = uct_chat;
1182         e->undo = uct_undo;
1183         e->result = uct_result;
1184         e->genmove = uct_genmove;
1185         e->genmoves = uct_genmoves;
1186         e->evaluate = uct_evaluate;
1187         e->dead_group_list = uct_dead_group_list;
1188         e->done = uct_done;
1189         e->data = u;
1190         if (u->slave)
1191                 e->notify = uct_notify;
1192
1193         const char banner[] = "If you believe you have won but I am still playing, "
1194                 "please help me understand by capturing all dead stones. "
1195                 "Anyone can send me 'winrate' in private chat to get my assessment of the position.";
1196         if (!u->banner) u->banner = "";
1197         e->comment = malloc2(sizeof(banner) + strlen(u->banner) + 1);
1198         sprintf(e->comment, "%s %s", banner, u->banner);
1199
1200         return e;
1201 }