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 "libmap.h"
  15 #include "move.h"
  16 #include "mq.h"
  17 #include "joseki/base.h"
  18 #include "playout.h"
  19 #include "playout/moggy.h"
  20 #include "playout/light.h"
  21 #include "tactics/util.h"
  22 #include "timeinfo.h"
  23 #include "uct/dynkomi.h"
  24 #include "uct/internal.h"
  25 #include "uct/plugins.h"
  26 #include "uct/prior.h"
  27 #include "uct/search.h"
  28 #include "uct/slave.h"
  29 #include "uct/tree.h"
  30 #include "uct/uct.h"
  31 #include "uct/walk.h"
  32
  33 struct uct_policy *policy_ucb1_init(struct uct *u, char *arg);
  34 struct uct_policy *policy_ucb1amaf_init(struct uct *u, char *arg, struct board *board);
  35 static void uct_pondering_start(struct uct *u, struct board *b0, struct tree *t, enum stone color);
  36
  37 /* Maximal simulation length. */
  38 #define MC_GAMELEN      MAX_GAMELEN
  39
  40
  41 static void
  42 setup_state(struct uct *u, struct board *b, enum stone color)
  43 {
  44         u->t = tree_init(b, color, u->fast_alloc ? u->max_tree_size : 0,
  45                          u->max_pruned_size, u->pruning_threshold, u->local_tree_aging, u->stats_hbits);
  46         if (u->initial_extra_komi)
  47                 u->t->extra_komi = u->initial_extra_komi;
  48         if (u->force_seed)
  49                 fast_srandom(u->force_seed);
  50         if (UDEBUGL(3))
  51                 fprintf(stderr, "Fresh board with random seed %lu\n", fast_getseed());
  52         if (!u->no_tbook && b->moves == 0) {
  53                 if (color == S_BLACK) {
  54                         tree_load(u->t, b);
  55                 } else if (DEBUGL(0)) {
  56                         fprintf(stderr, "Warning: First move appears to be white\n");
  57                 }
  58         }
  59 }
  60
  61 static void
  62 reset_state(struct uct *u)
  63 {
  64         assert(u->t);
  65         tree_done(u->t); u->t = NULL;
  66 }
  67
  68 static void
  69 setup_dynkomi(struct uct *u, struct board *b, enum stone to_play)
  70 {
  71         if (u->t->use_extra_komi && !u->pondering && u->dynkomi->permove)
  72                 u->t->extra_komi = u->dynkomi->permove(u->dynkomi, b, u->t);
  73         else if (!u->t->use_extra_komi)
  74                 u->t->extra_komi = 0;
  75 }
  76
  77 void
  78 uct_prepare_move(struct uct *u, struct board *b, enum stone color)
  79 {
  80         if (u->t) {
  81                 /* Verify that we have sane state. */
  82                 assert(b->es == u);
  83                 assert(u->t && b->moves);
  84                 if (color != stone_other(u->t->root_color)) {
  85                         fprintf(stderr, "Fatal: Non-alternating play detected %d %d\n",
  86                                 color, u->t->root_color);
  87                         exit(1);
  88                 }
  89                 uct_htable_reset(u->t);
  90
  91         } else {
  92                 /* We need fresh state. */
  93                 b->es = u;
  94                 setup_state(u, b, color);
  95         }
  96
  97         u->ownermap.playouts = 0;
  98         memset(u->ownermap.map, 0, board_size2(b) * sizeof(u->ownermap.map[0]));
  99         u->played_own = u->played_all = 0;
 100 }
 101
 102 static void
 103 dead_group_list(struct uct *u, struct board *b, struct move_queue *mq)
 104 {
 105         enum gj_state gs_array[board_size2(b)];
 106         struct group_judgement gj = { .thres = GJ_THRES, .gs = gs_array };
 107         board_ownermap_judge_groups(b, &u->ownermap, &gj);
 108         groups_of_status(b, &gj, GS_DEAD, mq);
 109 }
 110
 111 bool
 112 uct_pass_is_safe(struct uct *u, struct board *b, enum stone color, bool pass_all_alive)
 113 {
 114         /* Make sure enough playouts are simulated to get a reasonable dead group list. */
 115         while (u->ownermap.playouts < GJ_MINGAMES)
 116                 uct_playout(u, b, color, u->t);
 117
 118         struct move_queue mq = { .moves = 0 };
 119         dead_group_list(u, b, &mq);
 120         if (pass_all_alive) {
 121                 for (unsigned int i = 0; i < mq.moves; i++) {
 122                         if (board_at(b, mq.move[i]) == stone_other(color)) {
 123                                 return false; // We need to remove opponent dead groups first.
 124                         }
 125                 }
 126                 mq.moves = 0; // our dead stones are alive when pass_all_alive is true
 127         }
 128         if (u->allow_losing_pass) {
 129                 foreach_point(b) {
 130                         if (board_at(b, c) == S_OFFBOARD)
 131                                 continue;
 132                         if (board_ownermap_judge_point(&u->ownermap, c, GJ_THRES) == PJ_UNKNOWN) {
 133                                 if (UDEBUGL(3))
 134                                         fprintf(stderr, "uct_pass_is_safe fails at %s[%d]\n", coord2sstr(c, b), c);
 135                                 return false; // Unclear point, clarify first.
 136                         }
 137                 } foreach_point_end;
 138                 return true;
 139         }
 140         return pass_is_safe(b, color, &mq);
 141 }
 142
 143 static char *
 144 uct_printhook_ownermap(struct board *board, coord_t c, char *s, char *end)
 145 {
 146         struct uct *u = board->es;
 147         if (!u) {
 148                 strcat(s, ". ");
 149                 return s + 2;
 150         }
 151         const char chr[] = ":XO,"; // dame, black, white, unclear
 152         const char chm[] = ":xo,";
 153         char ch = chr[board_ownermap_judge_point(&u->ownermap, c, GJ_THRES)];
 154         if (ch == ',') { // less precise estimate then?
 155                 ch = chm[board_ownermap_judge_point(&u->ownermap, c, 0.67)];
 156         }
 157         s += snprintf(s, end - s, "%c ", ch);
 158         return s;
 159 }
 160
 161 static char *
 162 uct_notify_play(struct engine *e, struct board *b, struct move *m, char *enginearg)
 163 {
 164         struct uct *u = e->data;
 165         if (!u->t) {
 166                 /* No state, create one - this is probably game beginning
 167                  * and we need to load the opening tbook right now. */
 168                 uct_prepare_move(u, b, m->color);
 169                 assert(u->t);
 170         }
 171
 172         /* Stop pondering, required by tree_promote_at() */
 173         uct_pondering_stop(u);
 174         if (UDEBUGL(2) && u->slave)
 175                 tree_dump(u->t, u->dumpthres);
 176
 177         if (is_resign(m->coord)) {
 178                 /* Reset state. */
 179                 reset_state(u);
 180                 return NULL;
 181         }
 182
 183         /* Promote node of the appropriate move to the tree root. */
 184         assert(u->t->root);
 185         if (!tree_promote_at(u->t, b, m->coord)) {
 186                 if (UDEBUGL(3))
 187                         fprintf(stderr, "Warning: Cannot promote move node! Several play commands in row?\n");
 188                 /* Preserve dynamic komi information, though, that is important. */
 189                 u->initial_extra_komi = u->t->extra_komi;
 190                 reset_state(u);
 191                 return NULL;
 192         }
 193
 194         /* If we are a slave in a distributed engine, start pondering once
 195          * we know which move we actually played. See uct_genmove() about
 196          * the check for pass. */
 197         if (u->pondering_opt && u->slave && m->color == u->my_color && !is_pass(m->coord))
 198                 uct_pondering_start(u, b, u->t, stone_other(m->color));
 199
 200         return NULL;
 201 }
 202
 203 static char *
 204 uct_undo(struct engine *e, struct board *b)
 205 {
 206         struct uct *u = e->data;
 207
 208         if (!u->t) return NULL;
 209         uct_pondering_stop(u);
 210         u->initial_extra_komi = u->t->extra_komi;
 211         reset_state(u);
 212         return NULL;
 213 }
 214
 215 static char *
 216 uct_result(struct engine *e, struct board *b)
 217 {
 218         struct uct *u = e->data;
 219         static char reply[1024];
 220
 221         if (!u->t)
 222                 return NULL;
 223         enum stone color = u->t->root_color;
 224         struct tree_node *n = u->t->root;
 225         snprintf(reply, 1024, "%s %s %d %.2f %.1f",
 226                  stone2str(color), coord2sstr(node_coord(n), b),
 227                  n->u.playouts, tree_node_get_value(u->t, -1, n->u.value),
 228                  u->t->use_extra_komi ? u->t->extra_komi : 0);
 229         return reply;
 230 }
 231
 232 static char *
 233 uct_chat(struct engine *e, struct board *b, bool opponent, char *from, char *cmd)
 234 {
 235         struct uct *u = e->data;
 236
 237         if (!u->t)
 238                 return generic_chat(b, opponent, from, cmd, S_NONE, pass, 0, 1, u->threads, 0.0, 0.0);
 239
 240         struct tree_node *n = u->t->root;
 241         double winrate = tree_node_get_value(u->t, -1, n->u.value);
 242         double extra_komi = u->t->use_extra_komi && abs(u->t->extra_komi) >= 0.5 ? u->t->extra_komi : 0;
 243
 244         return generic_chat(b, opponent, from, cmd, u->t->root_color, node_coord(n), n->u.playouts, 1,
 245                             u->threads, winrate, extra_komi);
 246 }
 247
 248 static void
 249 uct_dead_group_list(struct engine *e, struct board *b, struct move_queue *mq)
 250 {
 251         struct uct *u = e->data;
 252
 253         /* This means the game is probably over, no use pondering on. */
 254         uct_pondering_stop(u);
 255
 256         if (u->pass_all_alive)
 257                 return; // no dead groups
 258
 259         bool mock_state = false;
 260
 261         if (!u->t) {
 262                 /* No state, but we cannot just back out - we might
 263                  * have passed earlier, only assuming some stones are
 264                  * dead, and then re-connected, only to lose counting
 265                  * when all stones are assumed alive. */
 266                 uct_prepare_move(u, b, S_BLACK); assert(u->t);
 267                 mock_state = true;
 268         }
 269         /* Make sure the ownermap is well-seeded. */
 270         while (u->ownermap.playouts < GJ_MINGAMES)
 271                 uct_playout(u, b, S_BLACK, u->t);
 272         /* Show the ownermap: */
 273         if (DEBUGL(2))
 274                 board_print_custom(b, stderr, uct_printhook_ownermap);
 275
 276         dead_group_list(u, b, mq);
 277
 278         if (mock_state) {
 279                 /* Clean up the mock state in case we will receive
 280                  * a genmove; we could get a non-alternating-move
 281                  * error from uct_prepare_move() in that case otherwise. */
 282                 reset_state(u);
 283         }
 284 }
 285
 286 static void
 287 playout_policy_done(struct playout_policy *p)
 288 {
 289         if (p->done) p->done(p);
 290         if (p->data) free(p->data);
 291         free(p);
 292 }
 293
 294 static void
 295 uct_done(struct engine *e)
 296 {
 297         /* This is called on engine reset, especially when clear_board
 298          * is received and new game should begin. */
 299         struct uct *u = e->data;
 300         uct_pondering_stop(u);
 301         if (u->t) reset_state(u);
 302         free(u->ownermap.map);
 303
 304         free(u->policy);
 305         free(u->random_policy);
 306         playout_policy_done(u->playout);
 307         uct_prior_done(u->prior);
 308         joseki_done(u->jdict);
 309         pluginset_done(u->plugins);
 310 }
 311
 312
 313
 314 /* Run time-limited MCTS search on foreground. */
 315 static int
 316 uct_search(struct uct *u, struct board *b, struct time_info *ti, enum stone color, struct tree *t, bool print_progress)
 317 {
 318         struct uct_search_state s;
 319         uct_search_start(u, b, color, t, ti, &s);
 320         if (UDEBUGL(2) && s.base_playouts > 0)
 321                 fprintf(stderr, "<pre-simulated %d games>\n", s.base_playouts);
 322
 323         /* The search tree is ctx->t. This is currently == . It is important
 324          * to reference ctx->t directly since the
 325          * thread manager will swap the tree pointer asynchronously. */
 326
 327         /* Now, just periodically poll the search tree. */
 328         /* Note that in case of TD_GAMES, threads will not wait for
 329          * the uct_search_check_stop() signalization. */
 330         while (1) {
 331                 time_sleep(TREE_BUSYWAIT_INTERVAL);
 332                 /* TREE_BUSYWAIT_INTERVAL should never be less than desired time, or the
 333                  * time control is broken. But if it happens to be less, we still search
 334                  * at least 100ms otherwise the move is completely random. */
 335
 336                 int i = uct_search_games(&s);
 337                 /* Print notifications etc. */
 338                 uct_search_progress(u, b, color, t, ti, &s, i);
 339                 /* Check if we should stop the search. */
 340                 if (uct_search_check_stop(u, b, color, t, ti, &s, i))
 341                         break;
 342         }
 343
 344         struct uct_thread_ctx *ctx = uct_search_stop();
 345         if (UDEBUGL(2)) tree_dump(t, u->dumpthres);
 346         if (UDEBUGL(2))
 347                 fprintf(stderr, "(avg score %f/%d; dynkomi's %f/%d value %f/%d)\n",
 348                         t->avg_score.value, t->avg_score.playouts,
 349                         u->dynkomi->score.value, u->dynkomi->score.playouts,
 350                         u->dynkomi->value.value, u->dynkomi->value.playouts);
 351         if (print_progress)
 352                 uct_progress_status(u, t, color, ctx->games, NULL);
 353
 354         u->played_own += ctx->games;
 355         return ctx->games;
 356 }
 357
 358 /* Start pondering background with @color to play. */
 359 static void
 360 uct_pondering_start(struct uct *u, struct board *b0, struct tree *t, enum stone color)
 361 {
 362         if (UDEBUGL(1))
 363                 fprintf(stderr, "Starting to ponder with color %s\n", stone2str(stone_other(color)));
 364         u->pondering = true;
 365
 366         /* We need a local board copy to ponder upon. */
 367         struct board *b = malloc2(sizeof(*b)); board_copy(b, b0);
 368
 369         /* *b0 did not have the genmove'd move played yet. */
 370         struct move m = { node_coord(t->root), t->root_color };
 371         int res = board_play(b, &m);
 372         assert(res >= 0);
 373         setup_dynkomi(u, b, stone_other(m.color));
 374
 375         /* Start MCTS manager thread "headless". */
 376         static struct uct_search_state s;
 377         uct_search_start(u, b, color, t, NULL, &s);
 378 }
 379
 380 /* uct_search_stop() frontend for the pondering (non-genmove) mode, and
 381  * to stop the background search for a slave in the distributed engine. */
 382 void
 383 uct_pondering_stop(struct uct *u)
 384 {
 385         if (!thread_manager_running)
 386                 return;
 387
 388         /* Stop the thread manager. */
 389         struct uct_thread_ctx *ctx = uct_search_stop();
 390         if (UDEBUGL(1)) {
 391                 if (u->pondering) fprintf(stderr, "(pondering) ");
 392                 uct_progress_status(u, ctx->t, ctx->color, ctx->games, NULL);
 393         }
 394         if (u->pondering) {
 395                 free(ctx->b);
 396                 u->pondering = false;
 397         }
 398 }
 399
 400
 401 void
 402 uct_genmove_setup(struct uct *u, struct board *b, enum stone color)
 403 {
 404         if (b->superko_violation) {
 405                 fprintf(stderr, "!!! WARNING: SUPERKO VIOLATION OCCURED BEFORE THIS MOVE\n");
 406                 fprintf(stderr, "Maybe you play with situational instead of positional superko?\n");
 407                 fprintf(stderr, "I'm going to ignore the violation, but note that I may miss\n");
 408                 fprintf(stderr, "some moves valid under this ruleset because of this.\n");
 409                 b->superko_violation = false;
 410         }
 411
 412         uct_prepare_move(u, b, color);
 413
 414         assert(u->t);
 415         u->my_color = color;
 416
 417         /* How to decide whether to use dynkomi in this game? Since we use
 418          * pondering, it's not simple "who-to-play" matter. Decide based on
 419          * the last genmove issued. */
 420         u->t->use_extra_komi = !!(u->dynkomi_mask & color);
 421         setup_dynkomi(u, b, color);
 422
 423         if (b->rules == RULES_JAPANESE)
 424                 u->territory_scoring = true;
 425
 426         /* Make pessimistic assumption about komi for Japanese rules to
 427          * avoid losing by 0.5 when winning by 0.5 with Chinese rules.
 428          * The rules usually give the same winner if the integer part of komi
 429          * is odd so we adjust the komi only if it is even (for a board of
 430          * odd size). We are not trying  to get an exact evaluation for rare
 431          * cases of seki. For details see http://home.snafu.de/jasiek/parity.html */
 432         if (u->territory_scoring && (((int)floor(b->komi) + board_size(b)) & 1)) {
 433                 b->komi += (color == S_BLACK ? 1.0 : -1.0);
 434                 if (UDEBUGL(0))
 435                         fprintf(stderr, "Setting komi to %.1f assuming Japanese rules\n",
 436                                 b->komi);
 437         }
 438 }
 439
 440 static coord_t *
 441 uct_genmove(struct engine *e, struct board *b, struct time_info *ti, enum stone color, bool pass_all_alive)
 442 {
 443         double start_time = time_now();
 444         struct uct *u = e->data;
 445         u->pass_all_alive |= pass_all_alive;
 446         uct_pondering_stop(u);
 447         uct_genmove_setup(u, b, color);
 448
 449         /* Start the Monte Carlo Tree Search! */
 450         int base_playouts = u->t->root->u.playouts;
 451         int played_games = uct_search(u, b, ti, color, u->t, false);
 452
 453         coord_t best_coord;
 454         struct tree_node *best;
 455         best = uct_search_result(u, b, color, u->pass_all_alive, played_games, base_playouts, &best_coord);
 456
 457         if (UDEBUGL(2)) {
 458                 double time = time_now() - start_time + 0.000001; /* avoid divide by zero */
 459                 fprintf(stderr, "genmove in %0.2fs (%d games/s, %d games/s/thread)\n",
 460                         time, (int)(played_games/time), (int)(played_games/time/u->threads));
 461         }
 462
 463         uct_progress_status(u, u->t, color, played_games, &best_coord);
 464
 465         if (!best) {
 466                 /* Pass or resign. */
 467                 if (is_pass(best_coord))
 468                         u->initial_extra_komi = u->t->extra_komi;
 469                 reset_state(u);
 470                 return coord_copy(best_coord);
 471         }
 472         tree_promote_node(u->t, &best);
 473
 474         /* After a pass, pondering is harmful for two reasons:
 475          * (i) We might keep pondering even when the game is over.
 476          * Of course this is the case for opponent resign as well.
 477          * (ii) More importantly, the ownermap will get skewed since
 478          * the UCT will start cutting off any playouts. */
 479         if (u->pondering_opt && !is_pass(node_coord(best))) {
 480                 uct_pondering_start(u, b, u->t, stone_other(color));
 481         }
 482         return coord_copy(best_coord);
 483 }
 484
 485
 486 bool
 487 uct_gentbook(struct engine *e, struct board *b, struct time_info *ti, enum stone color)
 488 {
 489         struct uct *u = e->data;
 490         if (!u->t) uct_prepare_move(u, b, color);
 491         assert(u->t);
 492
 493         if (ti->dim == TD_GAMES) {
 494                 /* Don't count in games that already went into the tbook. */
 495                 ti->len.games += u->t->root->u.playouts;
 496         }
 497         uct_search(u, b, ti, color, u->t, true);
 498
 499         assert(ti->dim == TD_GAMES);
 500         tree_save(u->t, b, ti->len.games / 100);
 501
 502         return true;
 503 }
 504
 505 void
 506 uct_dumptbook(struct engine *e, struct board *b, enum stone color)
 507 {
 508         struct uct *u = e->data;
 509         struct tree *t = tree_init(b, color, u->fast_alloc ? u->max_tree_size : 0,
 510                          u->max_pruned_size, u->pruning_threshold, u->local_tree_aging, 0);
 511         tree_load(t, b);
 512         tree_dump(t, 0);
 513         tree_done(t);
 514 }
 515
 516
 517 floating_t
 518 uct_evaluate_one(struct engine *e, struct board *b, struct time_info *ti, coord_t c, enum stone color)
 519 {
 520         struct uct *u = e->data;
 521
 522         struct board b2;
 523         board_copy(&b2, b);
 524         struct move m = { c, color };
 525         int res = board_play(&b2, &m);
 526         if (res < 0)
 527                 return NAN;
 528         color = stone_other(color);
 529
 530         if (u->t) reset_state(u);
 531         uct_prepare_move(u, &b2, color);
 532         assert(u->t);
 533
 534         floating_t bestval;
 535         uct_search(u, &b2, ti, color, u->t, true);
 536         struct tree_node *best = u->policy->choose(u->policy, u->t->root, &b2, color, resign);
 537         if (!best) {
 538                 bestval = NAN; // the opponent has no reply!
 539         } else {
 540                 bestval = tree_node_get_value(u->t, 1, best->u.value);
 541         }
 542
 543         reset_state(u); // clean our junk
 544
 545         return isnan(bestval) ? NAN : 1.0f - bestval;
 546 }
 547
 548 void
 549 uct_evaluate(struct engine *e, struct board *b, struct time_info *ti, floating_t *vals, enum stone color)
 550 {
 551         for (int i = 0; i < b->flen; i++) {
 552                 if (is_pass(b->f[i]))
 553                         vals[i] = NAN;
 554                 else
 555                         vals[i] = uct_evaluate_one(e, b, ti, b->f[i], color);
 556         }
 557 }
 558
 559
 560 struct uct *
 561 uct_state_init(char *arg, struct board *b)
 562 {
 563         struct uct *u = calloc2(1, sizeof(struct uct));
 564         bool pat_setup = false;
 565
 566         u->debug_level = debug_level;
 567         u->reportfreq = 10000;
 568         u->gamelen = MC_GAMELEN;
 569         u->resign_threshold = 0.2;
 570         u->sure_win_threshold = 0.95;
 571         u->mercymin = 0;
 572         u->significant_threshold = 50;
 573         u->expand_p = 8;
 574         u->dumpthres = 1000;
 575         u->playout_amaf = true;
 576         u->amaf_prior = false;
 577         u->max_tree_size = 1408ULL * 1048576;
 578         u->fast_alloc = true;
 579         u->pruning_threshold = 0;
 580
 581         u->threads = 1;
 582         u->thread_model = TM_TREEVL;
 583         u->virtual_loss = 1;
 584
 585         u->pondering_opt = true;
 586
 587         u->fuseki_end = 20; // max time at 361*20% = 72 moves (our 36th move, still 99 to play)
 588         u->yose_start = 40; // (100-40-25)*361/100/2 = 63 moves still to play by us then
 589         u->bestr_ratio = 0.02;
 590         // 2.5 is clearly too much, but seems to compensate well for overly stern time allocations.
 591         // TODO: Further tuning and experiments with better time allocation schemes.
 592         u->best2_ratio = 2.5;
 593         // Higher values of max_maintime_ratio sometimes cause severe time trouble in tournaments
 594         // It might be necessary to reduce it to 1.5 on large board, but more tuning is needed.
 595         u->max_maintime_ratio = 2.0;
 596
 597         u->val_scale = 0; u->val_points = 40;
 598         u->dynkomi_interval = 1000;
 599         u->dynkomi_mask = S_BLACK | S_WHITE;
 600
 601         u->tenuki_d = 4;
 602         u->local_tree_aging = 80;
 603         u->local_tree_depth_decay = 1.5;
 604         u->local_tree_eval = LTE_ROOT;
 605         u->local_tree_neival = true;
 606
 607         u->max_slaves = -1;
 608         u->slave_index = -1;
 609         u->stats_delay = 0.01; // 10 ms
 610         u->shared_levels = 1;
 611
 612         u->plugins = pluginset_init(b);
 613
 614         u->jdict = joseki_load(b->size);
 615
 616         if (arg) {
 617                 char *optspec, *next = arg;
 618                 while (*next) {
 619                         optspec = next;
 620                         next += strcspn(next, ",");
 621                         if (*next) { *next++ = 0; } else { *next = 0; }
 622
 623                         char *optname = optspec;
 624                         char *optval = strchr(optspec, '=');
 625                         if (optval) *optval++ = 0;
 626
 627                         /** Basic options */
 628
 629                         if (!strcasecmp(optname, "debug")) {
 630                                 if (optval)
 631                                         u->debug_level = atoi(optval);
 632                                 else
 633                                         u->debug_level++;
 634                         } else if (!strcasecmp(optname, "reporting") && optval) {
 635                                 /* The format of output for detailed progress
 636                                  * information (such as current best move and
 637                                  * its value, etc.). */
 638                                 if (!strcasecmp(optval, "text")) {
 639                                         /* Plaintext traditional output. */
 640                                         u->reporting = UR_TEXT;
 641                                 } else if (!strcasecmp(optval, "json")) {
 642                                         /* JSON output. Implies debug=0. */
 643                                         u->reporting = UR_JSON;
 644                                         u->debug_level = 0;
 645                                 } else if (!strcasecmp(optval, "jsonbig")) {
 646                                         /* JSON output, but much more detailed.
 647                                          * Implies debug=0. */
 648                                         u->reporting = UR_JSON_BIG;
 649                                         u->debug_level = 0;
 650                                 } else {
 651                                         fprintf(stderr, "UCT: Invalid reporting format %s\n", optval);
 652                                         exit(1);
 653                                 }
 654                         } else if (!strcasecmp(optname, "reportfreq") && optval) {
 655                                 /* The progress information line will be shown
 656                                  * every <reportfreq> simulations. */
 657                                 u->reportfreq = atoi(optval);
 658                         } else if (!strcasecmp(optname, "dumpthres") && optval) {
 659                                 /* When dumping the UCT tree on output, include
 660                                  * nodes with at least this many playouts.
 661                                  * (This value is re-scaled "intelligently"
 662                                  * in case of very large trees.) */
 663                                 u->dumpthres = atoi(optval);
 664                         } else if (!strcasecmp(optname, "resign_threshold") && optval) {
 665                                 /* Resign when this ratio of games is lost
 666                                  * after GJ_MINGAMES sample is taken. */
 667                                 u->resign_threshold = atof(optval);
 668                         } else if (!strcasecmp(optname, "sure_win_threshold") && optval) {
 669                                 /* Stop reading when this ratio of games is won
 670                                  * after PLAYOUT_EARLY_BREAK_MIN sample is
 671                                  * taken. (Prevents stupid time losses,
 672                                  * friendly to human opponents.) */
 673                                 u->sure_win_threshold = atof(optval);
 674                         } else if (!strcasecmp(optname, "force_seed") && optval) {
 675                                 /* Set RNG seed at the tree setup. */
 676                                 u->force_seed = atoi(optval);
 677                         } else if (!strcasecmp(optname, "no_tbook")) {
 678                                 /* Disable UCT opening tbook. */
 679                                 u->no_tbook = true;
 680                         } else if (!strcasecmp(optname, "pass_all_alive")) {
 681                                 /* Whether to consider passing only after all
 682                                  * dead groups were removed from the board;
 683                                  * this is like all genmoves are in fact
 684                                  * kgs-genmove_cleanup. */
 685                                 u->pass_all_alive = !optval || atoi(optval);
 686                         } else if (!strcasecmp(optname, "allow_losing_pass")) {
 687                                 /* Whether to consider passing in a clear
 688                                  * but losing situation, to be scored as a loss
 689                                  * for us. */
 690                                 u->allow_losing_pass = !optval || atoi(optval);
 691                         } else if (!strcasecmp(optname, "territory_scoring")) {
 692                                 /* Use territory scoring (default is area scoring).
 693                                  * An explicit kgs-rules command overrides this. */
 694                                 u->territory_scoring = !optval || atoi(optval);
 695                         } else if (!strcasecmp(optname, "stones_only")) {
 696                                 /* Do not count eyes. Nice to teach go to kids.
 697                                  * http://strasbourg.jeudego.org/regle_strasbourgeoise.htm */
 698                                 b->rules = RULES_STONES_ONLY;
 699                                 u->pass_all_alive = true;
 700                         } else if (!strcasecmp(optname, "banner") && optval) {
 701                                 /* Additional banner string. This must come as the
 702                                  * last engine parameter. */
 703                                 if (*next) *--next = ',';
 704                                 u->banner = strdup(optval);
 705                                 break;
 706                         } else if (!strcasecmp(optname, "plugin") && optval) {
 707                                 /* Load an external plugin; filename goes before the colon,
 708                                  * extra arguments after the colon. */
 709                                 char *pluginarg = strchr(optval, ':');
 710                                 if (pluginarg)
 711                                         *pluginarg++ = 0;
 712                                 plugin_load(u->plugins, optval, pluginarg);
 713
 714                         /** UCT behavior and policies */
 715
 716                         } else if ((!strcasecmp(optname, "policy")
 717                                 /* Node selection policy. ucb1amaf is the
 718                                  * default policy implementing RAVE, while
 719                                  * ucb1 is the simple exploration/exploitation
 720                                  * policy. Policies can take further extra
 721                                  * options. */
 722                                     || !strcasecmp(optname, "random_policy")) && optval) {
 723                                 /* A policy to be used randomly with small
 724                                  * chance instead of the default policy. */
 725                                 char *policyarg = strchr(optval, ':');
 726                                 struct uct_policy **p = !strcasecmp(optname, "policy") ? &u->policy : &u->random_policy;
 727                                 if (policyarg)
 728                                         *policyarg++ = 0;
 729                                 if (!strcasecmp(optval, "ucb1")) {
 730                                         *p = policy_ucb1_init(u, policyarg);
 731                                 } else if (!strcasecmp(optval, "ucb1amaf")) {
 732                                         *p = policy_ucb1amaf_init(u, policyarg, b);
 733                                 } else {
 734                                         fprintf(stderr, "UCT: Invalid tree policy %s\n", optval);
 735                                         exit(1);
 736                                 }
 737                         } else if (!strcasecmp(optname, "playout") && optval) {
 738                                 /* Random simulation (playout) policy.
 739                                  * moggy is the default policy with large
 740                                  * amount of domain-specific knowledge and
 741                                  * heuristics. light is a simple uniformly
 742                                  * random move selection policy. */
 743                                 char *playoutarg = strchr(optval, ':');
 744                                 if (playoutarg)
 745                                         *playoutarg++ = 0;
 746                                 if (!strcasecmp(optval, "moggy")) {
 747                                         u->playout = playout_moggy_init(playoutarg, b, u->jdict);
 748                                 } else if (!strcasecmp(optval, "light")) {
 749                                         u->playout = playout_light_init(playoutarg, b);
 750                                 } else {
 751                                         fprintf(stderr, "UCT: Invalid playout policy %s\n", optval);
 752                                         exit(1);
 753                                 }
 754                         } else if (!strcasecmp(optname, "prior") && optval) {
 755                                 /* Node priors policy. When expanding a node,
 756                                  * it will seed node values heuristically
 757                                  * (most importantly, based on playout policy
 758                                  * opinion, but also with regard to other
 759                                  * things). See uct/prior.c for details.
 760                                  * Use prior=eqex=0 to disable priors. */
 761                                 u->prior = uct_prior_init(optval, b, u);
 762                         } else if (!strcasecmp(optname, "mercy") && optval) {
 763                                 /* Minimal difference of black/white captures
 764                                  * to stop playout - "Mercy Rule". Speeds up
 765                                  * hopeless playouts at the expense of some
 766                                  * accuracy. */
 767                                 u->mercymin = atoi(optval);
 768                         } else if (!strcasecmp(optname, "gamelen") && optval) {
 769                                 /* Maximum length of single simulation
 770                                  * in moves. */
 771                                 u->gamelen = atoi(optval);
 772                         } else if (!strcasecmp(optname, "expand_p") && optval) {
 773                                 /* Expand UCT nodes after it has been
 774                                  * visited this many times. */
 775                                 u->expand_p = atoi(optval);
 776                         } else if (!strcasecmp(optname, "random_policy_chance") && optval) {
 777                                 /* If specified (N), with probability 1/N, random_policy policy
 778                                  * descend is used instead of main policy descend; useful
 779                                  * if specified policy (e.g. UCB1AMAF) can make unduly biased
 780                                  * choices sometimes, you can fall back to e.g.
 781                                  * random_policy=UCB1. */
 782                                 u->random_policy_chance = atoi(optval);
 783
 784                         /** General AMAF behavior */
 785                         /* (Only relevant if the policy supports AMAF.
 786                          * More variables can be tuned as policy
 787                          * parameters.) */
 788
 789                         } else if (!strcasecmp(optname, "playout_amaf")) {
 790                                 /* Whether to include random playout moves in
 791                                  * AMAF as well. (Otherwise, only tree moves
 792                                  * are included in AMAF. Of course makes sense
 793                                  * only in connection with an AMAF policy.) */
 794                                 /* with-without: 55.5% (+-4.1) */
 795                                 if (optval && *optval == '0')
 796                                         u->playout_amaf = false;
 797                                 else
 798                                         u->playout_amaf = true;
 799                         } else if (!strcasecmp(optname, "playout_amaf_cutoff") && optval) {
 800                                 /* Keep only first N% of playout stage AMAF
 801                                  * information. */
 802                                 u->playout_amaf_cutoff = atoi(optval);
 803                         } else if (!strcasecmp(optname, "amaf_prior") && optval) {
 804                                 /* In node policy, consider prior values
 805                                  * part of the real result term or part
 806                                  * of the AMAF term? */
 807                                 u->amaf_prior = atoi(optval);
 808
 809                         /** Performance and memory management */
 810
 811                         } else if (!strcasecmp(optname, "threads") && optval) {
 812                                 /* By default, Pachi will run with only single
 813                                  * tree search thread! */
 814                                 u->threads = atoi(optval);
 815                         } else if (!strcasecmp(optname, "thread_model") && optval) {
 816                                 if (!strcasecmp(optval, "tree")) {
 817                                         /* Tree parallelization - all threads
 818                                          * grind on the same tree. */
 819                                         u->thread_model = TM_TREE;
 820                                         u->virtual_loss = 0;
 821                                 } else if (!strcasecmp(optval, "treevl")) {
 822                                         /* Tree parallelization, but also
 823                                          * with virtual losses - this discou-
 824                                          * rages most threads choosing the
 825                                          * same tree branches to read. */
 826                                         u->thread_model = TM_TREEVL;
 827                                 } else {
 828                                         fprintf(stderr, "UCT: Invalid thread model %s\n", optval);
 829                                         exit(1);
 830                                 }
 831                         } else if (!strcasecmp(optname, "virtual_loss") && optval) {
 832                                 /* Number of virtual losses added before evaluating a node. */
 833                                 u->virtual_loss = atoi(optval);
 834                         } else if (!strcasecmp(optname, "pondering")) {
 835                                 /* Keep searching even during opponent's turn. */
 836                                 u->pondering_opt = !optval || atoi(optval);
 837                         } else if (!strcasecmp(optname, "max_tree_size") && optval) {
 838                                 /* Maximum amount of memory [MiB] consumed by the move tree.
 839                                  * For fast_alloc it includes the temp tree used for pruning.
 840                                  * Default is 3072 (3 GiB). */
 841                                 u->max_tree_size = atol(optval) * 1048576;
 842                         } else if (!strcasecmp(optname, "fast_alloc")) {
 843                                 u->fast_alloc = !optval || atoi(optval);
 844                         } else if (!strcasecmp(optname, "pruning_threshold") && optval) {
 845                                 /* Force pruning at beginning of a move if the tree consumes
 846                                  * more than this [MiB]. Default is 10% of max_tree_size.
 847                                  * Increase to reduce pruning time overhead if memory is plentiful.
 848                                  * This option is meaningful only for fast_alloc. */
 849                                 u->pruning_threshold = atol(optval) * 1048576;
 850
 851                         /** Time control */
 852
 853                         } else if (!strcasecmp(optname, "best2_ratio") && optval) {
 854                                 /* If set, prolong simulating while
 855                                  * first_best/second_best playouts ratio
 856                                  * is less than best2_ratio. */
 857                                 u->best2_ratio = atof(optval);
 858                         } else if (!strcasecmp(optname, "bestr_ratio") && optval) {
 859                                 /* If set, prolong simulating while
 860                                  * best,best_best_child values delta
 861                                  * is more than bestr_ratio. */
 862                                 u->bestr_ratio = atof(optval);
 863                         } else if (!strcasecmp(optname, "max_maintime_ratio") && optval) {
 864                                 /* If set and while not in byoyomi, prolong simulating no more than
 865                                  * max_maintime_ratio times the normal desired thinking time. */
 866                                 u->max_maintime_ratio = atof(optval);
 867                         } else if (!strcasecmp(optname, "fuseki_end") && optval) {
 868                                 /* At the very beginning it's not worth thinking
 869                                  * too long because the playout evaluations are
 870                                  * very noisy. So gradually increase the thinking
 871                                  * time up to maximum when fuseki_end percent
 872                                  * of the board has been played.
 873                                  * This only applies if we are not in byoyomi. */
 874                                 u->fuseki_end = atoi(optval);
 875                         } else if (!strcasecmp(optname, "yose_start") && optval) {
 876                                 /* When yose_start percent of the board has been
 877                                  * played, or if we are in byoyomi, stop spending
 878                                  * more time and spread the remaining time
 879                                  * uniformly.
 880                                  * Between fuseki_end and yose_start, we spend
 881                                  * a constant proportion of the remaining time
 882                                  * on each move. (yose_start should actually
 883                                  * be much earlier than when real yose start,
 884                                  * but "yose" is a good short name to convey
 885                                  * the idea.) */
 886                                 u->yose_start = atoi(optval);
 887
 888                         /** Dynamic komi */
 889
 890                         } else if (!strcasecmp(optname, "dynkomi") && optval) {
 891                                 /* Dynamic komi approach; there are multiple
 892                                  * ways to adjust komi dynamically throughout
 893                                  * play. We currently support two: */
 894                                 char *dynkomiarg = strchr(optval, ':');
 895                                 if (dynkomiarg)
 896                                         *dynkomiarg++ = 0;
 897                                 if (!strcasecmp(optval, "none")) {
 898                                         u->dynkomi = uct_dynkomi_init_none(u, dynkomiarg, b);
 899                                 } else if (!strcasecmp(optval, "linear")) {
 900                                         /* You should set dynkomi_mask=1 or a very low
 901                                          * handicap_value for white. */
 902                                         u->dynkomi = uct_dynkomi_init_linear(u, dynkomiarg, b);
 903                                 } else if (!strcasecmp(optval, "adaptive")) {
 904                                         /* There are many more knobs to
 905                                          * crank - see uct/dynkomi.c. */
 906                                         u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomiarg, b);
 907                                 } else {
 908                                         fprintf(stderr, "UCT: Invalid dynkomi mode %s\n", optval);
 909                                         exit(1);
 910                                 }
 911                         } else if (!strcasecmp(optname, "dynkomi_mask") && optval) {
 912                                 /* Bitmask of colors the player must be
 913                                  * for dynkomi be applied; the default dynkomi_mask=3 allows
 914                                  * dynkomi even in games where Pachi is white. */
 915                                 u->dynkomi_mask = atoi(optval);
 916                         } else if (!strcasecmp(optname, "dynkomi_interval") && optval) {
 917                                 /* If non-zero, re-adjust dynamic komi
 918                                  * throughout a single genmove reading,
 919                                  * roughly every N simulations. */
 920                                 /* XXX: Does not work with tree
 921                                  * parallelization. */
 922                                 u->dynkomi_interval = atoi(optval);
 923                         } else if (!strcasecmp(optname, "extra_komi") && optval) {
 924                                 /* Initial dynamic komi settings. This
 925                                  * is useful for the adaptive dynkomi
 926                                  * policy as the value to start with
 927                                  * (this is NOT kept fixed) in case
 928                                  * there is not enough time in the search
 929                                  * to adjust the value properly (e.g. the
 930                                  * game was interrupted). */
 931                                 u->initial_extra_komi = atof(optval);
 932
 933                         /** Node value result scaling */
 934
 935                         } else if (!strcasecmp(optname, "val_scale") && optval) {
 936                                 /* How much of the game result value should be
 937                                  * influenced by win size. Zero means it isn't. */
 938                                 u->val_scale = atof(optval);
 939                         } else if (!strcasecmp(optname, "val_points") && optval) {
 940                                 /* Maximum size of win to be scaled into game
 941                                  * result value. Zero means boardsize^2. */
 942                                 u->val_points = atoi(optval) * 2; // result values are doubled
 943                         } else if (!strcasecmp(optname, "val_extra")) {
 944                                 /* If false, the score coefficient will be simply
 945                                  * added to the value, instead of scaling the result
 946                                  * coefficient because of it. */
 947                                 u->val_extra = !optval || atoi(optval);
 948                         } else if (!strcasecmp(optname, "val_byavg")) {
 949                                 /* If true, the score included in the value will
 950                                  * be relative to average score in the current
 951                                  * search episode inst. of jigo. */
 952                                 u->val_byavg = !optval || atoi(optval);
 953                         } else if (!strcasecmp(optname, "val_bytemp")) {
 954                                 /* If true, the value scaling coefficient
 955                                  * is different based on value extremity
 956                                  * (dist. from 0.5), linear between
 957                                  * val_bytemp_min, val_scale. */
 958                                 u->val_bytemp = !optval || atoi(optval);
 959                         } else if (!strcasecmp(optname, "val_bytemp_min") && optval) {
 960                                 /* Minimum val_scale in case of val_bytemp. */
 961                                 u->val_bytemp_min = atof(optval);
 962
 963                         /** Local trees */
 964                         /* (Purely experimental. Does not work - yet!) */
 965
 966                         } else if (!strcasecmp(optname, "local_tree")) {
 967                                 /* Whether to bias exploration by local tree values. */
 968                                 u->local_tree = !optval || atoi(optval);
 969                         } else if (!strcasecmp(optname, "tenuki_d") && optval) {
 970                                 /* Tenuki distance at which to break the local tree. */
 971                                 u->tenuki_d = atoi(optval);
 972                                 if (u->tenuki_d > TREE_NODE_D_MAX + 1) {
 973                                         fprintf(stderr, "uct: tenuki_d must not be larger than TREE_NODE_D_MAX+1 %d\n", TREE_NODE_D_MAX + 1);
 974                                         exit(1);
 975                                 }
 976                         } else if (!strcasecmp(optname, "local_tree_aging") && optval) {
 977                                 /* How much to reduce local tree values between moves. */
 978                                 u->local_tree_aging = atof(optval);
 979                         } else if (!strcasecmp(optname, "local_tree_depth_decay") && optval) {
 980                                 /* With value x>0, during the descent the node
 981                                  * contributes 1/x^depth playouts in
 982                                  * the local tree. I.e., with x>1, nodes more
 983                                  * distant from local situation contribute more
 984                                  * than nodes near the root. */
 985                                 u->local_tree_depth_decay = atof(optval);
 986                         } else if (!strcasecmp(optname, "local_tree_allseq")) {
 987                                 /* If disabled, only complete sequences are stored
 988                                  * in the local tree. If this is on, also
 989                                  * subsequences starting at each move are stored. */
 990                                 u->local_tree_allseq = !optval || atoi(optval);
 991                         } else if (!strcasecmp(optname, "local_tree_neival")) {
 992                                 /* If disabled, local node value is not
 993                                  * computed just based on terminal status
 994                                  * of the coordinate, but also its neighbors. */
 995                                 u->local_tree_neival = !optval || atoi(optval);
 996                         } else if (!strcasecmp(optname, "local_tree_eval")) {
 997                                 /* How is the value inserted in the local tree
 998                                  * determined. */
 999                                 if (!strcasecmp(optval, "root"))
1000                                         /* All moves within a tree branch are
1001                                          * considered wrt. their merit
1002                                          * reaching tachtical goal of making
1003                                          * the first move in the branch
1004                                          * survive. */
1005                                         u->local_tree_eval = LTE_ROOT;
1006                                 else if (!strcasecmp(optval, "each"))
1007                                         /* Each move is considered wrt.
1008                                          * its own survival. */
1009                                         u->local_tree_eval = LTE_EACH;
1010                                 else if (!strcasecmp(optval, "total"))
1011                                         /* The tactical goal is the survival
1012                                          * of all the moves of my color and
1013                                          * non-survival of all the opponent
1014                                          * moves. Local values (and their
1015                                          * inverses) are averaged. */
1016                                         u->local_tree_eval = LTE_TOTAL;
1017                                 else {
1018                                         fprintf(stderr, "uct: unknown local_tree_eval %s\n", optval);
1019                                         exit(1);
1020                                 }
1021                         } else if (!strcasecmp(optname, "local_tree_rootchoose")) {
1022                                 /* If disabled, only moves within the local
1023                                  * tree branch are considered; the values
1024                                  * of the branch roots (i.e. root children)
1025                                  * are ignored. This may make sense together
1026                                  * with eval!=each, we consider only moves
1027                                  * that influence the goal, not the "rating"
1028                                  * of the goal itself. (The real solution
1029                                  * will be probably using criticality to pick
1030                                  * local tree branches.) */
1031                                 u->local_tree_rootchoose = !optval || atoi(optval);
1032
1033                         /** Other heuristics */
1034                         } else if (!strcasecmp(optname, "patterns")) {
1035                                 /* Load pattern database. Various modules
1036                                  * (priors, policies etc.) may make use
1037                                  * of this database. They will request
1038                                  * it automatically in that case, but you
1039                                  * can use this option to tweak the pattern
1040                                  * parameters. */
1041                                 patterns_init(&u->pat, optval, false, true);
1042                                 u->want_pat = pat_setup = true;
1043                         } else if (!strcasecmp(optname, "significant_threshold") && optval) {
1044                                 /* Some heuristics (XXX: none in mainline) rely
1045                                  * on the knowledge of the last "significant"
1046                                  * node in the descent. Such a node is
1047                                  * considered reasonably trustworthy to carry
1048                                  * some meaningful information in the values
1049                                  * of the node and its children. */
1050                                 u->significant_threshold = atoi(optval);
1051                         } else if (!strcasecmp(optname, "libmap")) {
1052                                 /* Online learning of move tactical ratings by
1053                                  * liberty maps. */
1054                                 libmap_setup(optval);
1055                                 libmap_init(b);
1056
1057                         /** Distributed engine slaves setup */
1058
1059                         } else if (!strcasecmp(optname, "slave")) {
1060                                 /* Act as slave for the distributed engine. */
1061                                 u->slave = !optval || atoi(optval);
1062                         } else if (!strcasecmp(optname, "slave_index") && optval) {
1063                                 /* Optional index if per-slave behavior is desired.
1064                                  * Must be given as index/max */
1065                                 u->slave_index = atoi(optval);
1066                                 char *p = strchr(optval, '/');
1067                                 if (p) u->max_slaves = atoi(++p);
1068                         } else if (!strcasecmp(optname, "shared_nodes") && optval) {
1069                                 /* Share at most shared_nodes between master and slave at each genmoves.
1070                                  * Must use the same value in master and slaves. */
1071                                 u->shared_nodes = atoi(optval);
1072                         } else if (!strcasecmp(optname, "shared_levels") && optval) {
1073                                 /* Share only nodes of level <= shared_levels. */
1074                                 u->shared_levels = atoi(optval);
1075                         } else if (!strcasecmp(optname, "stats_hbits") && optval) {
1076                                 /* Set hash table size to 2^stats_hbits for the shared stats. */
1077                                 u->stats_hbits = atoi(optval);
1078                         } else if (!strcasecmp(optname, "stats_delay") && optval) {
1079                                 /* How long to wait in slave for initial stats to build up before
1080                                  * replying to the genmoves command (in ms) */
1081                                 u->stats_delay = 0.001 * atof(optval);
1082
1083                         /** Presets */
1084
1085                         } else if (!strcasecmp(optname, "maximize_score")) {
1086                                 /* A combination of settings that will make
1087                                  * Pachi try to maximize his points (instead
1088                                  * of playing slack yose) or minimize his loss
1089                                  * (and proceed to counting even when losing). */
1090                                 /* Please note that this preset might be
1091                                  * somewhat weaker than normal Pachi, and the
1092                                  * score maximization is approximate; point size
1093                                  * of win/loss still should not be used to judge
1094                                  * strength of Pachi or the opponent. */
1095                                 /* See README for some further notes. */
1096                                 if (!optval || atoi(optval)) {
1097                                         /* Allow scoring a lost game. */
1098                                         u->allow_losing_pass = true;
1099                                         /* Make Pachi keep his calm when losing
1100                                          * and/or maintain winning marging. */
1101                                         /* Do not play games that are losing
1102                                          * by too much. */
1103                                         /* XXX: komi_ratchet_age=40000 is necessary
1104                                          * with losing_komi_ratchet, but 40000
1105                                          * is somewhat arbitrary value. */
1106                                         char dynkomi_args[] = "losing_komi_ratchet:komi_ratchet_age=60000:no_komi_at_game_end=0:max_losing_komi=30";
1107                                         u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomi_args, b);
1108                                         /* XXX: Values arbitrary so far. */
1109                                         /* XXX: Also, is bytemp sensible when
1110                                          * combined with dynamic komi?! */
1111                                         u->val_scale = 0.01;
1112                                         u->val_bytemp = true;
1113                                         u->val_bytemp_min = 0.001;
1114                                         u->val_byavg = true;
1115                                 }
1116
1117                         } else {
1118                                 fprintf(stderr, "uct: Invalid engine argument %s or missing value\n", optname);
1119                                 exit(1);
1120                         }
1121                 }
1122         }
1123
1124         if (!u->policy)
1125                 u->policy = policy_ucb1amaf_init(u, NULL, b);
1126
1127         if (!!u->random_policy_chance ^ !!u->random_policy) {
1128                 fprintf(stderr, "uct: Only one of random_policy and random_policy_chance is set\n");
1129                 exit(1);
1130         }
1131
1132         if (!u->local_tree) {
1133                 /* No ltree aging. */
1134                 u->local_tree_aging = 1.0f;
1135         }
1136
1137         if (u->fast_alloc) {
1138                 if (u->pruning_threshold < u->max_tree_size / 10)
1139                         u->pruning_threshold = u->max_tree_size / 10;
1140                 if (u->pruning_threshold > u->max_tree_size / 2)
1141                         u->pruning_threshold = u->max_tree_size / 2;
1142
1143                 /* Limit pruning temp space to 20% of memory. Beyond this we discard
1144                  * the nodes and recompute them at the next move if necessary. */
1145                 u->max_pruned_size = u->max_tree_size / 5;
1146                 u->max_tree_size -= u->max_pruned_size;
1147         } else {
1148                 /* Reserve 5% memory in case the background free() are slower
1149                  * than the concurrent allocations. */
1150                 u->max_tree_size -= u->max_tree_size / 20;
1151         }
1152
1153         if (!u->prior)
1154                 u->prior = uct_prior_init(NULL, b, u);
1155
1156         if (!u->playout)
1157                 u->playout = playout_moggy_init(NULL, b, u->jdict);
1158         if (!u->playout->debug_level)
1159                 u->playout->debug_level = u->debug_level;
1160
1161         if (u->want_pat && !pat_setup)
1162                 patterns_init(&u->pat, NULL, false, true);
1163
1164         u->ownermap.map = malloc2(board_size2(b) * sizeof(u->ownermap.map[0]));
1165
1166         if (u->slave) {
1167                 if (!u->stats_hbits) u->stats_hbits = DEFAULT_STATS_HBITS;
1168                 if (!u->shared_nodes) u->shared_nodes = DEFAULT_SHARED_NODES;
1169                 assert(u->shared_levels * board_bits2(b) <= 8 * (int)sizeof(path_t));
1170         }
1171
1172         if (!u->dynkomi)
1173                 u->dynkomi = board_small(b) ? uct_dynkomi_init_none(u, NULL, b)
1174                         : uct_dynkomi_init_linear(u, NULL, b);
1175
1176         /* Some things remain uninitialized for now - the opening tbook
1177          * is not loaded and the tree not set up. */
1178         /* This will be initialized in setup_state() at the first move
1179          * received/requested. This is because right now we are not aware
1180          * about any komi or handicap setup and such. */
1181
1182         return u;
1183 }
1184
1185 struct engine *
1186 engine_uct_init(char *arg, struct board *b)
1187 {
1188         struct uct *u = uct_state_init(arg, b);
1189         struct engine *e = calloc2(1, sizeof(struct engine));
1190         e->name = "UCT";
1191         e->printhook = uct_printhook_ownermap;
1192         e->notify_play = uct_notify_play;
1193         e->chat = uct_chat;
1194         e->undo = uct_undo;
1195         e->result = uct_result;
1196         e->genmove = uct_genmove;
1197         e->genmoves = uct_genmoves;
1198         e->evaluate = uct_evaluate;
1199         e->dead_group_list = uct_dead_group_list;
1200         e->done = uct_done;
1201         e->data = u;
1202         if (u->slave)
1203                 e->notify = uct_notify;
1204
1205         const char banner[] = "If you believe you have won but I am still playing, "
1206                 "please help me understand by capturing all dead stones. "
1207                 "Anyone can send me 'winrate' in private chat to get my assessment of the position.";
1208         if (!u->banner) u->banner = "";
1209         e->comment = malloc2(sizeof(banner) + strlen(u->banner) + 1);
1210         sprintf(e->comment, "%s %s", banner, u->banner);
1211
1212         return e;
1213 }