uct/uct.c

   1 #include <assert.h>
   2 #include <pthread.h>
   3 #include <signal.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7
   8 #define DEBUG
   9
  10 #include "debug.h"
  11 #include "board.h"
  12 #include "move.h"
  13 #include "playout.h"
  14 #include "playout/moggy.h"
  15 #include "playout/old.h"
  16 #include "playout/light.h"
  17 #include "random.h"
  18 #include "uct/internal.h"
  19 #include "uct/tree.h"
  20 #include "uct/uct.h"
  21
  22 struct uct_policy *policy_ucb1_init(struct uct *u, char *arg);
  23 struct uct_policy *policy_ucb1tuned_init(struct uct *u, char *arg);
  24 struct uct_policy *policy_ucb1amaf_init(struct uct *u, char *arg);
  25
  26
  27 #define MC_GAMES        80000
  28 #define MC_GAMELEN      400
  29
  30
  31 static void
  32 progress_status(struct uct *u, struct tree *t, enum stone color, int playouts)
  33 {
  34         if (!UDEBUGL(0))
  35                 return;
  36
  37         /* Best move */
  38         struct tree_node *best = u->policy->choose(u->policy, t->root, t->board, color);
  39         if (!best) {
  40                 fprintf(stderr, "... No moves left\n");
  41                 return;
  42         }
  43         fprintf(stderr, "[%d] ", playouts);
  44         fprintf(stderr, "best %f ", best->u.value);
  45
  46         /* Max depth */
  47         fprintf(stderr, "deepest % 2d ", t->max_depth - t->root->depth);
  48
  49         /* Best sequence */
  50         fprintf(stderr, "| seq ");
  51         for (int depth = 0; depth < 6; depth++) {
  52                 if (best && best->u.playouts >= 25) {
  53                         fprintf(stderr, "%3s ", coord2sstr(best->coord, t->board));
  54                         best = u->policy->choose(u->policy, best, t->board, color);
  55                 } else {
  56                         fprintf(stderr, "    ");
  57                 }
  58         }
  59
  60         /* Best candidates */
  61         fprintf(stderr, "| can ");
  62         int cans = 4;
  63         struct tree_node *can[cans];
  64         memset(can, 0, sizeof(can));
  65         best = t->root->children;
  66         while (best) {
  67                 int c = 0;
  68                 while ((!can[c] || best->u.playouts > can[c]->u.playouts) && ++c < cans);
  69                 for (int d = 0; d < c; d++) can[d] = can[d + 1];
  70                 if (c > 0) can[c - 1] = best;
  71                 best = best->sibling;
  72         }
  73         while (--cans >= 0) {
  74                 if (can[cans]) {
  75                         fprintf(stderr, "%3s(%.3f) ", coord2sstr(can[cans]->coord, t->board), can[cans]->u.value);
  76                 } else {
  77                         fprintf(stderr, "           ");
  78                 }
  79         }
  80
  81         fprintf(stderr, "\n");
  82 }
  83
  84
  85 static int
  86 uct_leaf_node(struct uct *u, struct board *b, enum stone player_color,
  87               struct playout_amafmap *amaf,
  88               struct tree *t, struct tree_node *n, enum stone node_color,
  89               char *spaces)
  90 {
  91         enum stone next_color = stone_other(node_color);
  92         if (n->u.playouts >= u->expand_p)
  93                 tree_expand_node(t, n, b, next_color, u->radar_d, u->policy,
  94                                  (next_color == player_color ? 1 : -1));
  95         if (UDEBUGL(7))
  96                 fprintf(stderr, "%s*-- UCT playout #%d start [%s] %f\n",
  97                         spaces, n->u.playouts, coord2sstr(n->coord, t->board), n->u.value);
  98
  99         int result = play_random_game(&b2, next_color, u->gamelen, u->playout_amaf ? amaf : NULL, u->playout);
 100         if (player_color != next_color && result >= 0)
 101                 result = !result;
 102         if (UDEBUGL(7))
 103                 fprintf(stderr, "%s -- [%d..%d] %s random playout result %d\n",
 104                         spaces, player_color, next_color, coord2sstr(n->coord, t->board), result);
 105
 106         return result;
 107 }
 108
 109 static int
 110 uct_playout(struct uct *u, struct board *b, enum stone player_color, struct tree *t)
 111 {
 112         struct board b2;
 113         board_copy(&b2, b);
 114
 115         struct playout_amafmap *amaf = NULL;
 116         if (u->policy->wants_amaf) {
 117                 amaf = calloc(1, sizeof(*amaf));
 118                 amaf->map = calloc(board_size2(&b2) + 1, sizeof(*amaf->map));
 119                 amaf->map++; // -1 is pass
 120         }
 121
 122         /* Walk the tree until we find a leaf, then expand it and do
 123          * a random playout. */
 124         struct tree_node *n = t->root;
 125         enum stone node_color = stone_other(player_color);
 126         int result;
 127         int pass_limit = (board_size(&b2) - 2) * (board_size(&b2) - 2) / 2;
 128         int passes = is_pass(b->last_move.coord);
 129         /* debug */
 130         int depth = 0;
 131         static char spaces[] = "\0                                                      ";
 132         /* /debug */
 133         if (UDEBUGL(8))
 134                 fprintf(stderr, "--- UCT walk with color %d\n", player_color);
 135         while (!tree_leaf_node(n)) {
 136                 spaces[depth++] = ' '; spaces[depth] = 0;
 137
 138                 n = u->policy->descend(u->policy, t, n, (node_color == player_color ? -1 : 1), pass_limit);
 139                 node_color = stone_other(node_color);
 140                 assert(n == t->root || n->parent);
 141                 if (UDEBUGL(7))
 142                         fprintf(stderr, "%s+-- UCT sent us to [%s:%d] %f\n",
 143                                 spaces, coord2sstr(n->coord, t->board), n->coord, n->u.value);
 144                 if (amaf && n->coord >= -1 && !is_pass(n->coord)) {
 145                         if (amaf->map[n->coord] == S_NONE) {
 146                                 amaf->map[n->coord] = node_color;
 147                         } else {
 148                                 amaf_op(amaf->map[n->coord], +);
 149                         }
 150                 }
 151                 struct move m = { n->coord, node_color };
 152                 int res = board_play(&b2, &m);
 153
 154                 if (res < 0 || (!is_pass(m.coord) && !group_at(&b2, m.coord)) /* suicide */
 155                     || b2.superko_violation) {
 156                         if (UDEBUGL(3)) {
 157                                 for (struct tree_node *ni = n; ni; ni = ni->parent)
 158                                         fprintf(stderr, "%s ", coord2sstr(ni->coord, t->board));
 159                                 fprintf(stderr, "deleting invalid %s node %d,%d res %d group %d spk %d\n",
 160                                         stone2str(node_color), coord_x(n->coord,b), coord_y(n->coord,b),
 161                                         res, group_at(&b2, m.coord), b2.superko_violation);
 162                         }
 163                         tree_delete_node(t, n);
 164                         result = -1;
 165                         goto end;
 166                 }
 167
 168                 if (is_pass(n->coord)) {
 169                         passes++;
 170                         if (passes >= 2) {
 171                                 float score = board_official_score(&b2);
 172                                 result = (player_color == S_BLACK) ? score < 0 : score > 0;
 173                                 if (UDEBUGL(5))
 174                                         fprintf(stderr, "[%d..%d] %s p-p scoring playout result %d (W %f)\n",
 175                                                 player_color, node_color, coord2sstr(n->coord, t->board), result, score);
 176                                 if (UDEBUGL(6))
 177                                         board_print(&b2, stderr);
 178                                 goto update;
 179                         }
 180                 } else {
 181                         passes = 0;
 182                 }
 183         }
 184
 185         /* Found a leaf node! */
 186         result = uct_leaf_node(u, &b2, player_color, amaf, t, n, node_color, spaces);
 187
 188 update:
 189         assert(n == t->root || n->parent);
 190         if (result >= 0)
 191                 u->policy->update(u->policy, t, n, node_color, player_color, amaf, result);
 192
 193 end:
 194         if (amaf) {
 195                 free(amaf->map - 1);
 196                 free(amaf);
 197         }
 198         board_done_noalloc(&b2);
 199         return result;
 200 }
 201
 202 static void
 203 prepare_move(struct engine *e, struct board *b, enum stone color, coord_t promote)
 204 {
 205         struct uct *u = e->data;
 206
 207         if (!b->moves && u->t) {
 208                 /* Stale state from last game */
 209                 tree_done(u->t);
 210                 u->t = NULL;
 211         }
 212
 213         if (!u->t) {
 214                 u->t = tree_init(b, color);
 215                 if (u->force_seed)
 216                         fast_srandom(u->force_seed);
 217                 if (UDEBUGL(0))
 218                         fprintf(stderr, "Fresh board with random seed %lu\n", fast_getseed());
 219                 //board_print(b, stderr);
 220                 tree_load(u->t, b, color);
 221         }
 222
 223         /* XXX: We hope that the opponent didn't suddenly play
 224          * several moves in the row. */
 225         if (!is_resign(promote) && !tree_promote_at(u->t, b, promote)) {
 226                 if (UDEBUGL(2))
 227                         fprintf(stderr, "<cannot find node to promote>\n");
 228                 /* Reset tree */
 229                 tree_done(u->t);
 230                 u->t = tree_init(b, color);
 231         }
 232 }
 233
 234 /* Set in main thread in case the playouts should stop. */
 235 static volatile sig_atomic_t halt = 0;
 236
 237 static int
 238 uct_playouts(struct uct *u, struct board *b, enum stone color, struct tree *t)
 239 {
 240         int i, games = u->games;
 241         if (t->root->children)
 242                 games -= t->root->u.playouts / 1.5;
 243         /* else this is highly read-out but dead-end branch of opening book;
 244          * we need to start from scratch; XXX: Maybe actually base the readout
 245          * count based on number of playouts of best node? */
 246         for (i = 0; i < games; i++) {
 247                 int result = uct_playout(u, b, color, t);
 248                 if (result < 0) {
 249                         /* Tree descent has hit invalid move. */
 250                         continue;
 251                 }
 252
 253                 if (i > 0 && !(i % 10000)) {
 254                         progress_status(u, t, color, i);
 255                 }
 256
 257                 if (i > 0 && !(i % 500)) {
 258                         struct tree_node *best = u->policy->choose(u->policy, t->root, b, color);
 259                         if (best && best->u.playouts >= 1500 && best->u.value >= u->loss_threshold)
 260                                 break;
 261                 }
 262
 263                 if (halt) {
 264                         if (UDEBUGL(2))
 265                                 fprintf(stderr, "<halting early, %d games skipped>\n", games - i);
 266                         break;
 267                 }
 268         }
 269
 270         progress_status(u, t, color, i);
 271         if (UDEBUGL(3))
 272                 tree_dump(t, u->dumpthres);
 273         return i;
 274 }
 275
 276 static pthread_mutex_t finish_mutex = PTHREAD_MUTEX_INITIALIZER;
 277 static pthread_cond_t finish_cond = PTHREAD_COND_INITIALIZER;
 278 static volatile int finish_thread;
 279 static pthread_mutex_t finish_serializer = PTHREAD_MUTEX_INITIALIZER;
 280
 281 struct spawn_ctx {
 282         int tid;
 283         struct uct *u;
 284         struct board *b;
 285         enum stone color;
 286         struct tree *t;
 287         unsigned long seed;
 288         int games;
 289 };
 290
 291 static void *
 292 spawn_helper(void *ctx_)
 293 {
 294         struct spawn_ctx *ctx = ctx_;
 295         /* Setup */
 296         fast_srandom(ctx->seed);
 297         /* Run */
 298         ctx->games = uct_playouts(ctx->u, ctx->b, ctx->color, ctx->t);
 299         /* Finish */
 300         pthread_mutex_lock(&finish_serializer);
 301         pthread_mutex_lock(&finish_mutex);
 302         finish_thread = ctx->tid;
 303         pthread_cond_signal(&finish_cond);
 304         pthread_mutex_unlock(&finish_mutex);
 305         return ctx;
 306 }
 307
 308 static void
 309 uct_notify_play(struct engine *e, struct board *b, struct move *m)
 310 {
 311         prepare_move(e, b, stone_other(m->color), m->coord);
 312 }
 313
 314 static coord_t *
 315 uct_genmove(struct engine *e, struct board *b, enum stone color)
 316 {
 317         struct uct *u = e->data;
 318
 319         /* Seed the tree. */
 320         prepare_move(e, b, color, resign);
 321
 322         int played_games = 0;
 323         if (!u->threads) {
 324                 played_games = uct_playouts(u, b, color, u->t);
 325         } else {
 326                 pthread_t threads[u->threads];
 327                 int joined = 0;
 328                 halt = 0;
 329                 pthread_mutex_lock(&finish_mutex);
 330                 /* Spawn threads... */
 331                 for (int ti = 0; ti < u->threads; ti++) {
 332                         struct spawn_ctx *ctx = malloc(sizeof(*ctx));
 333                         ctx->u = u; ctx->b = b; ctx->color = color;
 334                         ctx->t = tree_copy(u->t); ctx->tid = ti;
 335                         ctx->seed = fast_random(65536) + ti;
 336                         pthread_create(&threads[ti], NULL, spawn_helper, ctx);
 337                         if (UDEBUGL(2))
 338                                 fprintf(stderr, "Spawned thread %d\n", ti);
 339                 }
 340                 /* ...and collect them back: */
 341                 while (joined < u->threads) {
 342                         /* Wait for some thread to finish... */
 343                         pthread_cond_wait(&finish_cond, &finish_mutex);
 344                         /* ...and gather its remnants. */
 345                         struct spawn_ctx *ctx;
 346                         pthread_join(threads[finish_thread], (void **) &ctx);
 347                         played_games += ctx->games;
 348                         joined++;
 349                         tree_merge(u->t, ctx->t);
 350                         tree_done(ctx->t);
 351                         free(ctx);
 352                         if (UDEBUGL(2))
 353                                 fprintf(stderr, "Joined thread %d\n", finish_thread);
 354                         /* Do not get stalled by slow threads. */
 355                         if (joined >= u->threads / 2)
 356                                 halt = 1;
 357                         pthread_mutex_unlock(&finish_serializer);
 358                 }
 359                 pthread_mutex_unlock(&finish_mutex);
 360         }
 361
 362         if (UDEBUGL(2))
 363                 tree_dump(u->t, u->dumpthres);
 364
 365         struct tree_node *best = u->policy->choose(u->policy, u->t->root, b, color);
 366         if (!best) {
 367                 tree_done(u->t); u->t = NULL;
 368                 return coord_copy(pass);
 369         }
 370         if (UDEBUGL(0))
 371                 fprintf(stderr, "*** WINNER is %s (%d,%d) with score %1.4f (%d/%d:%d games)\n", coord2sstr(best->coord, b), coord_x(best->coord, b), coord_y(best->coord, b), best->u.value, best->u.playouts, u->t->root->u.playouts, played_games);
 372         if (best->u.value < u->resign_ratio && !is_pass(best->coord)) {
 373                 tree_done(u->t); u->t = NULL;
 374                 return coord_copy(resign);
 375         }
 376         tree_promote_node(u->t, best);
 377         return coord_copy(best->coord);
 378 }
 379
 380 bool
 381 uct_genbook(struct engine *e, struct board *b, enum stone color)
 382 {
 383         struct uct *u = e->data;
 384         u->t = tree_init(b, color);
 385         tree_load(u->t, b, color);
 386
 387         int i;
 388         for (i = 0; i < u->games; i++) {
 389                 int result = uct_playout(u, b, color, u->t);
 390                 if (result < 0) {
 391                         /* Tree descent has hit invalid move. */
 392                         continue;
 393                 }
 394
 395                 if (i > 0 && !(i % 10000)) {
 396                         progress_status(u, u->t, color, i);
 397                 }
 398         }
 399         progress_status(u, u->t, color, i);
 400
 401         tree_save(u->t, b, u->games / 100);
 402
 403         tree_done(u->t);
 404
 405         return true;
 406 }
 407
 408 void
 409 uct_dumpbook(struct engine *e, struct board *b, enum stone color)
 410 {
 411         struct uct *u = e->data;
 412         u->t = tree_init(b, color);
 413         tree_load(u->t, b, color);
 414         tree_dump(u->t, 0);
 415         tree_done(u->t);
 416 }
 417
 418
 419 struct uct *
 420 uct_state_init(char *arg)
 421 {
 422         struct uct *u = calloc(1, sizeof(struct uct));
 423
 424         u->debug_level = 1;
 425         u->games = MC_GAMES;
 426         u->gamelen = MC_GAMELEN;
 427         u->expand_p = 2;
 428         u->dumpthres = 1000;
 429         u->playout_amaf = false;
 430
 431         if (arg) {
 432                 char *optspec, *next = arg;
 433                 while (*next) {
 434                         optspec = next;
 435                         next += strcspn(next, ",");
 436                         if (*next) { *next++ = 0; } else { *next = 0; }
 437
 438                         char *optname = optspec;
 439                         char *optval = strchr(optspec, '=');
 440                         if (optval) *optval++ = 0;
 441
 442                         if (!strcasecmp(optname, "debug")) {
 443                                 if (optval)
 444                                         u->debug_level = atoi(optval);
 445                                 else
 446                                         u->debug_level++;
 447                         } else if (!strcasecmp(optname, "games") && optval) {
 448                                 u->games = atoi(optval);
 449                         } else if (!strcasecmp(optname, "gamelen") && optval) {
 450                                 u->gamelen = atoi(optval);
 451                         } else if (!strcasecmp(optname, "expand_p") && optval) {
 452                                 u->expand_p = atoi(optval);
 453                         } else if (!strcasecmp(optname, "radar_d") && optval) {
 454                                 /* For 19x19, it is good idea to set this to 3. */
 455                                 u->radar_d = atoi(optval);
 456                         } else if (!strcasecmp(optname, "dumpthres") && optval) {
 457                                 u->dumpthres = atoi(optval);
 458                         } else if (!strcasecmp(optname, "playout_amaf")) {
 459                                 /* Whether to include random playout moves in
 460                                  * AMAF as well. (Otherwise, only tree moves
 461                                  * are included in AMAF. Of course makes sense
 462                                  * only in connection with an AMAF policy.) */
 463                                 /* with-without: 55.5% (+-4.1) */
 464                                 if (optval && *optval == '0')
 465                                         u->playout_amaf = false;
 466                                 else
 467                                         u->playout_amaf = true;
 468                         } else if (!strcasecmp(optname, "policy") && optval) {
 469                                 char *policyarg = strchr(optval, ':');
 470                                 if (policyarg)
 471                                         *policyarg++ = 0;
 472                                 if (!strcasecmp(optval, "ucb1")) {
 473                                         u->policy = policy_ucb1_init(u, policyarg);
 474                                 } else if (!strcasecmp(optval, "ucb1tuned")) {
 475                                         u->policy = policy_ucb1tuned_init(u, policyarg);
 476                                 } else if (!strcasecmp(optval, "ucb1amaf")) {
 477                                         u->policy = policy_ucb1amaf_init(u, policyarg);
 478                                 } else {
 479                                         fprintf(stderr, "UCT: Invalid tree policy %s\n", optval);
 480                                 }
 481                         } else if (!strcasecmp(optname, "playout") && optval) {
 482                                 char *playoutarg = strchr(optval, ':');
 483                                 if (playoutarg)
 484                                         *playoutarg++ = 0;
 485                                 if (!strcasecmp(optval, "old")) {
 486                                         u->playout = playout_old_init(playoutarg);
 487                                 } else if (!strcasecmp(optval, "moggy")) {
 488                                         u->playout = playout_moggy_init(playoutarg);
 489                                 } else if (!strcasecmp(optval, "light")) {
 490                                         u->playout = playout_light_init(playoutarg);
 491                                 } else {
 492                                         fprintf(stderr, "UCT: Invalid playout policy %s\n", optval);
 493                                 }
 494                         } else if (!strcasecmp(optname, "threads") && optval) {
 495                                 u->threads = atoi(optval);
 496                         } else if (!strcasecmp(optname, "force_seed") && optval) {
 497                                 u->force_seed = atoi(optval);
 498                         } else {
 499                                 fprintf(stderr, "uct: Invalid engine argument %s or missing value\n", optname);
 500                         }
 501                 }
 502         }
 503
 504         u->resign_ratio = 0.2; /* Resign when most games are lost. */
 505         u->loss_threshold = 0.85; /* Stop reading if after at least 1500 playouts this is best value. */
 506         if (!u->policy)
 507                 u->policy = policy_ucb1amaf_init(u, NULL);
 508
 509         if (!u->playout)
 510                 u->playout = playout_moggy_init(NULL);
 511         u->playout->debug_level = u->debug_level;
 512
 513         return u;
 514 }
 515
 516
 517 struct engine *
 518 engine_uct_init(char *arg)
 519 {
 520         struct uct *u = uct_state_init(arg);
 521         struct engine *e = calloc(1, sizeof(struct engine));
 522         e->name = "UCT Engine";
 523         e->comment = "I'm playing UCT. When we both pass, I will consider all the stones on the board alive. If you are reading this, write 'yes'. Please bear with me at the game end, I need to fill the whole board; if you help me, we will both be happier. Filling the board will not lose points (NZ rules).";
 524         e->genmove = uct_genmove;
 525         e->notify_play = uct_notify_play;
 526         e->data = u;
 527
 528         return e;
 529 }