uct/tree.c

   1 #include <assert.h>
   2 #include <math.h>
   3 #include <stddef.h>
   4 #include <stdint.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9 #define DEBUG
  10 #include "board.h"
  11 #include "debug.h"
  12 #include "engine.h"
  13 #include "move.h"
  14 #include "playout.h"
  15 #include "tactics.h"
  16 #include "uct/internal.h"
  17 #include "uct/prior.h"
  18 #include "uct/tree.h"
  19
  20
  21 static struct tree_node *
  22 tree_init_node(struct tree *t, coord_t coord, int depth)
  23 {
  24         struct tree_node *n = calloc(1, sizeof(*n));
  25         if (!n) {
  26                 fprintf(stderr, "tree_init_node(): OUT OF MEMORY\n");
  27                 exit(1);
  28         }
  29         n->coord = coord;
  30         n->depth = depth;
  31         static long c = 1000000;
  32         n->hash = c++;
  33         if (depth > t->max_depth)
  34                 t->max_depth = depth;
  35         return n;
  36 }
  37
  38 struct tree *
  39 tree_init(struct board *board, enum stone color)
  40 {
  41         struct tree *t = calloc(1, sizeof(*t));
  42         t->board = board;
  43         /* The root PASS move is only virtual, we never play it. */
  44         t->root = tree_init_node(t, pass, 0);
  45         t->root_symmetry = board->symmetry;
  46         t->root_color = stone_other(color); // to research black moves, root will be white
  47         pthread_mutex_init(&t->expansion_mutex, NULL);
  48         return t;
  49 }
  50
  51
  52 static void
  53 tree_done_node(struct tree *t, struct tree_node *n)
  54 {
  55         struct tree_node *ni = n->children;
  56         while (ni) {
  57                 struct tree_node *nj = ni->sibling;
  58                 tree_done_node(t, ni);
  59                 ni = nj;
  60         }
  61         free(n);
  62 }
  63
  64 void
  65 tree_done(struct tree *t)
  66 {
  67         tree_done_node(t, t->root);
  68         if (t->chchvals) free(t->chchvals);
  69         if (t->chvals) free(t->chvals);
  70         free(t);
  71 }
  72
  73
  74 static void
  75 tree_node_dump(struct tree *tree, struct tree_node *node, int l, int thres)
  76 {
  77         for (int i = 0; i < l; i++) fputc(' ', stderr);
  78         int children = 0;
  79         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
  80                 children++;
  81         /* We use 1 as parity, since for all nodes we want to know the
  82          * win probability of _us_, not the node color. */
  83         fprintf(stderr, "[%s] %f %% %d [prior %f %% %d amaf %f %% %d]; hints %x; %d children <%"PRIhash">\n",
  84                 coord2sstr(node->coord, tree->board),
  85                 tree_node_get_value(tree, 1, node->u.value), node->u.playouts,
  86                 tree_node_get_value(tree, 1, node->prior.value), node->prior.playouts,
  87                 tree_node_get_value(tree, 1, node->amaf.value), node->amaf.playouts,
  88                 node->hints, children, node->hash);
  89
  90         /* Print nodes sorted by #playouts. */
  91
  92         struct tree_node *nbox[1000]; int nboxl = 0;
  93         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
  94                 if (ni->u.playouts > thres)
  95                         nbox[nboxl++] = ni;
  96
  97         while (true) {
  98                 int best = -1;
  99                 for (int i = 0; i < nboxl; i++)
 100                         if (nbox[i] && (best < 0 || nbox[i]->u.playouts > nbox[best]->u.playouts))
 101                                 best = i;
 102                 if (best < 0)
 103                         break;
 104                 tree_node_dump(tree, nbox[best], l + 1, /* node->u.value < 0.1 ? 0 : */ thres);
 105                 nbox[best] = NULL;
 106         }
 107 }
 108
 109 void
 110 tree_dump_chval(struct tree *tree, struct move_stats *v)
 111 {
 112         for (int y = board_size(tree->board) - 2; y > 1; y--) {
 113                 for (int x = 1; x < board_size(tree->board) - 1; x++) {
 114                         coord_t c = coord_xy(tree->board, x, y);
 115                         fprintf(stderr, "%.2f%%%05d  ", v[c].value, v[c].playouts);
 116                 }
 117                 fprintf(stderr, "\n");
 118         }
 119 }
 120
 121 void
 122 tree_dump(struct tree *tree, int thres)
 123 {
 124         if (thres && tree->root->u.playouts / thres > 100) {
 125                 /* Be a bit sensible about this; the opening book can create
 126                  * huge dumps at first. */
 127                 thres = tree->root->u.playouts / 100 * (thres < 1000 ? 1 : thres / 1000);
 128         }
 129         fprintf(stderr, "(UCT tree; root %s; extra komi %f)\n",
 130                 stone2str(tree->root_color), tree->extra_komi);
 131         tree_node_dump(tree, tree->root, 0, thres);
 132
 133         if (DEBUGL(3) && tree->chvals) {
 134                 fprintf(stderr, "children stats:\n");
 135                 tree_dump_chval(tree, tree->chvals);
 136                 fprintf(stderr, "grandchildren stats:\n");
 137                 tree_dump_chval(tree, tree->chchvals);
 138         }
 139 }
 140
 141
 142 static char *
 143 tree_book_name(struct board *b)
 144 {
 145         static char buf[256];
 146         if (b->handicap > 0) {
 147                 sprintf(buf, "uctbook-%d-%02.01f-h%d.pachitree", b->size - 2, b->komi, b->handicap);
 148         } else {
 149                 sprintf(buf, "uctbook-%d-%02.01f.pachitree", b->size - 2, b->komi);
 150         }
 151         return buf;
 152 }
 153
 154 static void
 155 tree_node_save(FILE *f, struct tree_node *node, int thres)
 156 {
 157         fputc(1, f);
 158         fwrite(((void *) node) + offsetof(struct tree_node, depth),
 159                sizeof(struct tree_node) - offsetof(struct tree_node, depth),
 160                1, f);
 161
 162         if (node->u.playouts >= thres)
 163                 for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 164                         tree_node_save(f, ni, thres);
 165
 166         fputc(0, f);
 167 }
 168
 169 void
 170 tree_save(struct tree *tree, struct board *b, int thres)
 171 {
 172         char *filename = tree_book_name(b);
 173         FILE *f = fopen(filename, "wb");
 174         if (!f) {
 175                 perror("fopen");
 176                 return;
 177         }
 178         tree_node_save(f, tree->root, thres);
 179         fputc(0, f);
 180         fclose(f);
 181 }
 182
 183
 184 void
 185 tree_node_load(FILE *f, struct tree_node *node, int *num)
 186 {
 187         (*num)++;
 188
 189         fread(((void *) node) + offsetof(struct tree_node, depth),
 190                sizeof(struct tree_node) - offsetof(struct tree_node, depth),
 191                1, f);
 192
 193         /* Keep values in sane scale, otherwise we start overflowing. */
 194 #define MAX_PLAYOUTS    10000000
 195         if (node->u.playouts > MAX_PLAYOUTS) {
 196                 node->u.playouts = MAX_PLAYOUTS;
 197         }
 198         if (node->amaf.playouts > MAX_PLAYOUTS) {
 199                 node->amaf.playouts = MAX_PLAYOUTS;
 200         }
 201
 202         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 203         memcpy(&node->pu, &node->u, sizeof(node->u));
 204
 205         struct tree_node *ni = NULL, *ni_prev = NULL;
 206         while (fgetc(f)) {
 207                 ni_prev = ni; ni = calloc(1, sizeof(*ni));
 208                 if (!node->children)
 209                         node->children = ni;
 210                 else
 211                         ni_prev->sibling = ni;
 212                 ni->parent = node;
 213                 tree_node_load(f, ni, num);
 214         }
 215 }
 216
 217 void
 218 tree_load(struct tree *tree, struct board *b)
 219 {
 220         char *filename = tree_book_name(b);
 221         FILE *f = fopen(filename, "rb");
 222         if (!f)
 223                 return;
 224
 225         fprintf(stderr, "Loading opening book %s...\n", filename);
 226
 227         int num = 0;
 228         if (fgetc(f))
 229                 tree_node_load(f, tree->root, &num);
 230         fprintf(stderr, "Loaded %d nodes.\n", num);
 231
 232         fclose(f);
 233 }
 234
 235
 236 static struct tree_node *
 237 tree_node_copy(struct tree_node *node)
 238 {
 239         struct tree_node *n2 = malloc(sizeof(*n2));
 240         *n2 = *node;
 241         if (!node->children)
 242                 return n2;
 243         struct tree_node *ni = node->children;
 244         struct tree_node *ni2 = tree_node_copy(ni);
 245         n2->children = ni2; ni2->parent = n2;
 246         while ((ni = ni->sibling)) {
 247                 ni2->sibling = tree_node_copy(ni);
 248                 ni2 = ni2->sibling; ni2->parent = n2;
 249         }
 250         return n2;
 251 }
 252
 253 struct tree *
 254 tree_copy(struct tree *tree)
 255 {
 256         struct tree *t2 = malloc(sizeof(*t2));
 257         *t2 = *tree;
 258         t2->root = tree_node_copy(tree->root);
 259         return t2;
 260 }
 261
 262
 263 static void
 264 tree_node_merge(struct tree_node *dest, struct tree_node *src)
 265 {
 266         /* Do not merge nodes that weren't touched at all. */
 267         assert(dest->pamaf.playouts == src->pamaf.playouts);
 268         assert(dest->pu.playouts == src->pu.playouts);
 269         if (src->amaf.playouts - src->pamaf.playouts == 0
 270             && src->u.playouts - src->pu.playouts == 0) {
 271                 return;
 272         }
 273
 274         dest->hints |= src->hints;
 275
 276         /* Merge the children, both are coord-sorted lists. */
 277         struct tree_node *di = dest->children, **dref = &dest->children;
 278         struct tree_node *si = src->children, **sref = &src->children;
 279         while (di && si) {
 280                 if (di->coord != si->coord) {
 281                         /* src has some extra items or misses di */
 282                         struct tree_node *si2 = si->sibling;
 283                         while (si2 && di->coord != si2->coord) {
 284                                 si2 = si2->sibling;
 285                         }
 286                         if (!si2)
 287                                 goto next_di; /* src misses di, move on */
 288                         /* chain the extra [si,si2) items before di */
 289                         (*dref) = si;
 290                         while (si->sibling != si2) {
 291                                 si->parent = dest;
 292                                 si = si->sibling;
 293                         }
 294                         si->parent = dest;
 295                         si->sibling = di;
 296                         si = si2;
 297                         (*sref) = si;
 298                 }
 299                 /* Matching nodes - recurse... */
 300                 tree_node_merge(di, si);
 301                 /* ...and move on. */
 302                 sref = &si->sibling; si = si->sibling;
 303 next_di:
 304                 dref = &di->sibling; di = di->sibling;
 305         }
 306         if (si) {
 307                 /* Some outstanding nodes are left on src side, rechain
 308                  * them to dst. */
 309                 (*dref) = si;
 310                 while (si) {
 311                         si->parent = dest;
 312                         si = si->sibling;
 313                 }
 314                 (*sref) = NULL;
 315         }
 316
 317         /* Priors should be constant. */
 318         assert(dest->prior.playouts == src->prior.playouts && dest->prior.value == src->prior.value);
 319
 320         stats_merge(&dest->amaf, &src->amaf);
 321         stats_merge(&dest->u, &src->u);
 322 }
 323
 324 /* Merge two trees built upon the same board. Note that the operation is
 325  * destructive on src. */
 326 void
 327 tree_merge(struct tree *dest, struct tree *src)
 328 {
 329         if (src->max_depth > dest->max_depth)
 330                 dest->max_depth = src->max_depth;
 331         tree_node_merge(dest->root, src->root);
 332 }
 333
 334
 335 static void
 336 tree_node_normalize(struct tree_node *node, int factor)
 337 {
 338         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 339                 tree_node_normalize(ni, factor);
 340
 341 #define normalize(s1, s2, t) node->s2.t = node->s1.t + (node->s2.t - node->s1.t) / factor;
 342         normalize(pamaf, amaf, playouts);
 343         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 344
 345         normalize(pu, u, playouts);
 346         memcpy(&node->pu, &node->u, sizeof(node->u));
 347 #undef normalize
 348 }
 349
 350 /* Normalize a tree, dividing the amaf and u values by given
 351  * factor; otherwise, simulations run in independent threads
 352  * two trees built upon the same board. To correctly handle
 353  * results taken from previous simulation run, they are backed
 354  * up in tree. */
 355 void
 356 tree_normalize(struct tree *tree, int factor)
 357 {
 358         tree_node_normalize(tree->root, factor);
 359 }
 360
 361
 362 /* Get a node of given coordinate from within parent, possibly creating it
 363  * if necessary - in a very raw form (no .d, priors, ...). */
 364 /* FIXME: Adjust for board symmetry. */
 365 struct tree_node *
 366 tree_get_node(struct tree *t, struct tree_node *parent, coord_t c, bool create)
 367 {
 368         if (!parent->children || parent->children->coord >= c) {
 369                 /* Special case: Insertion at the beginning. */
 370                 if (parent->children && parent->children->coord == c)
 371                         return parent->children;
 372                 if (!create)
 373                         return NULL;
 374
 375                 struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 376                 nn->parent = parent; nn->sibling = parent->children;
 377                 parent->children = nn;
 378                 return nn;
 379         }
 380
 381         /* No candidate at the beginning, look through all the children. */
 382
 383         struct tree_node *ni;
 384         for (ni = parent->children; ni->sibling; ni = ni->sibling)
 385                 if (ni->sibling->coord >= c)
 386                         break;
 387
 388         if (ni->sibling && ni->sibling->coord == c)
 389                 return ni->sibling;
 390         assert(ni->coord < c);
 391         if (!create)
 392                 return NULL;
 393
 394         struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 395         nn->parent = parent; nn->sibling = ni->sibling; ni->sibling = nn;
 396         return nn;
 397 }
 398
 399
 400 /* Tree symmetry: When possible, we will localize the tree to a single part
 401  * of the board in tree_expand_node() and possibly flip along symmetry axes
 402  * to another part of the board in tree_promote_at(). We follow b->symmetry
 403  * guidelines here. */
 404
 405
 406 void
 407 tree_expand_node(struct tree *t, struct tree_node *node, struct board *b, enum stone color, struct uct *u, int parity)
 408 {
 409         /* Get a Common Fate Graph distance map from parent node. */
 410         int distances[board_size2(b)];
 411         if (!is_pass(b->last_move.coord) && !is_resign(b->last_move.coord)) {
 412                 cfg_distances(b, node->coord, distances, TREE_NODE_D_MAX);
 413         } else {
 414                 // Pass or resign - everything is too far.
 415                 foreach_point(b) { distances[c] = TREE_NODE_D_MAX + 1; } foreach_point_end;
 416         }
 417
 418         /* Get a map of prior values to initialize the new nodes with. */
 419         struct prior_map map = {
 420                 .b = b,
 421                 .to_play = color,
 422                 .parity = tree_parity(t, parity),
 423                 .distances = distances,
 424         };
 425         // Include pass in the prior map.
 426         struct move_stats map_prior[board_size2(b) + 1]; map.prior = &map_prior[1];
 427         bool map_consider[board_size2(b) + 1]; map.consider = &map_consider[1];
 428         memset(map_prior, 0, sizeof(map_prior));
 429         memset(map_consider, 0, sizeof(map_consider));
 430         struct move pm = { .color = color };
 431         map.consider[pass] = true;
 432         foreach_point(b) {
 433                 if (board_at(b, c) != S_NONE)
 434                         continue;
 435                 pm.coord = c;
 436                 if (!board_is_valid_move(b, &pm))
 437                         continue;
 438                 map.consider[c] = true;
 439         } foreach_point_end;
 440         uct_prior(u, node, &map);
 441
 442         /* Now, create the nodes. */
 443         struct tree_node *ni = tree_init_node(t, pass, node->depth + 1);
 444         struct tree_node *first_child = ni;
 445         ni->parent = node;
 446         ni->prior = map.prior[pass]; ni->d = TREE_NODE_D_MAX + 1;
 447
 448         /* The loop considers only the symmetry playground. */
 449         if (UDEBUGL(6)) {
 450                 fprintf(stderr, "expanding %s within [%d,%d],[%d,%d] %d-%d\n",
 451                                 coord2sstr(node->coord, b),
 452                                 b->symmetry.x1, b->symmetry.y1,
 453                                 b->symmetry.x2, b->symmetry.y2,
 454                                 b->symmetry.type, b->symmetry.d);
 455         }
 456         for (int i = b->symmetry.x1; i <= b->symmetry.x2; i++) {
 457                 for (int j = b->symmetry.y1; j <= b->symmetry.y2; j++) {
 458                         if (b->symmetry.d) {
 459                                 int x = b->symmetry.type == SYM_DIAG_DOWN ? board_size(b) - 1 - i : i;
 460                                 if (x > j) {
 461                                         if (UDEBUGL(7))
 462                                                 fprintf(stderr, "drop %d,%d\n", i, j);
 463                                         continue;
 464                                 }
 465                         }
 466
 467                         coord_t c = coord_xy_otf(i, j, t->board);
 468                         if (!map.consider[c]) // Filter out invalid moves
 469                                 continue;
 470                         assert(c != node->coord); // I have spotted "C3 C3" in some sequence...
 471
 472                         struct tree_node *nj = tree_init_node(t, c, node->depth + 1);
 473                         nj->parent = node; ni->sibling = nj; ni = nj;
 474
 475                         ni->prior = map.prior[c];
 476                         ni->d = distances[c];
 477                 }
 478         }
 479         node->children = first_child; // must be done at the end to avoid race
 480 }
 481
 482
 483 static coord_t
 484 flip_coord(struct board *b, coord_t c,
 485            bool flip_horiz, bool flip_vert, int flip_diag)
 486 {
 487         int x = coord_x(c, b), y = coord_y(c, b);
 488         if (flip_diag) {
 489                 int z = x; x = y; y = z;
 490         }
 491         if (flip_horiz) {
 492                 x = board_size(b) - 1 - x;
 493         }
 494         if (flip_vert) {
 495                 y = board_size(b) - 1 - y;
 496         }
 497         return coord_xy_otf(x, y, b);
 498 }
 499
 500 static void
 501 tree_fix_node_symmetry(struct board *b, struct tree_node *node,
 502                        bool flip_horiz, bool flip_vert, int flip_diag)
 503 {
 504         if (!is_pass(node->coord))
 505                 node->coord = flip_coord(b, node->coord, flip_horiz, flip_vert, flip_diag);
 506
 507         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 508                 tree_fix_node_symmetry(b, ni, flip_horiz, flip_vert, flip_diag);
 509 }
 510
 511 static void
 512 tree_fix_symmetry(struct tree *tree, struct board *b, coord_t c)
 513 {
 514         if (is_pass(c))
 515                 return;
 516
 517         struct board_symmetry *s = &tree->root_symmetry;
 518         int cx = coord_x(c, b), cy = coord_y(c, b);
 519
 520         /* playground   X->h->v->d normalization
 521          * :::..        .d...
 522          * .::..        v....
 523          * ..:..        .....
 524          * .....        h...X
 525          * .....        .....  */
 526         bool flip_horiz = cx < s->x1 || cx > s->x2;
 527         bool flip_vert = cy < s->y1 || cy > s->y2;
 528
 529         bool flip_diag = 0;
 530         if (s->d) {
 531                 bool dir = (s->type == SYM_DIAG_DOWN);
 532                 int x = dir ^ flip_horiz ^ flip_vert ? board_size(b) - 1 - cx : cx;
 533                 if (flip_vert ? x < cy : x > cy) {
 534                         flip_diag = 1;
 535                 }
 536         }
 537
 538         if (DEBUGL(4)) {
 539                 fprintf(stderr, "%s [%d,%d -> %d,%d;%d,%d] will flip %d %d %d -> %s, sym %d (%d) -> %d (%d)\n",
 540                         coord2sstr(c, b),
 541                         cx, cy, s->x1, s->y1, s->x2, s->y2,
 542                         flip_horiz, flip_vert, flip_diag,
 543                         coord2sstr(flip_coord(b, c, flip_horiz, flip_vert, flip_diag), b),
 544                         s->type, s->d, b->symmetry.type, b->symmetry.d);
 545         }
 546         if (flip_horiz || flip_vert || flip_diag)
 547                 tree_fix_node_symmetry(b, tree->root, flip_horiz, flip_vert, flip_diag);
 548 }
 549
 550
 551 static void
 552 tree_unlink_node(struct tree_node *node)
 553 {
 554         struct tree_node *ni = node->parent;
 555         if (ni->children == node) {
 556                 ni->children = node->sibling;
 557         } else {
 558                 ni = ni->children;
 559                 while (ni->sibling != node)
 560                         ni = ni->sibling;
 561                 ni->sibling = node->sibling;
 562         }
 563         node->sibling = NULL;
 564         node->parent = NULL;
 565 }
 566
 567 void
 568 tree_delete_node(struct tree *tree, struct tree_node *node)
 569 {
 570         tree_unlink_node(node);
 571         tree_done_node(tree, node);
 572 }
 573
 574 void
 575 tree_promote_node(struct tree *tree, struct tree_node *node)
 576 {
 577         assert(node->parent == tree->root);
 578         tree_unlink_node(node);
 579         tree_done_node(tree, tree->root);
 580         tree->root = node;
 581         tree->root_color = stone_other(tree->root_color);
 582         board_symmetry_update(tree->board, &tree->root_symmetry, node->coord);
 583         tree->max_depth--;
 584         if (tree->chchvals) { free(tree->chchvals); tree->chchvals = NULL; }
 585         if (tree->chvals) { free(tree->chvals); tree->chvals = NULL; }
 586 }
 587
 588 bool
 589 tree_promote_at(struct tree *tree, struct board *b, coord_t c)
 590 {
 591         tree_fix_symmetry(tree, b, c);
 592
 593         for (struct tree_node *ni = tree->root->children; ni; ni = ni->sibling) {
 594                 if (ni->coord == c) {
 595                         tree_promote_node(tree, ni);
 596                         return true;
 597                 }
 598         }
 599         return false;
 600 }