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 /* This function may be called by multiple threads in parallel */
  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         __sync_fetch_and_add(&t->node_sizes, sizeof(*n));
  30         n->coord = coord;
  31         n->depth = depth;
  32         volatile static long c = 1000000;
  33         n->hash = __sync_fetch_and_add(&c, 1) - 1;
  34         if (depth > t->max_depth)
  35                 t->max_depth = depth;
  36         return n;
  37 }
  38
  39 struct tree *
  40 tree_init(struct board *board, enum stone color)
  41 {
  42         struct tree *t = calloc(1, sizeof(*t));
  43         t->board = board;
  44         /* The root PASS move is only virtual, we never play it. */
  45         t->root = tree_init_node(t, pass, 0);
  46         t->root_symmetry = board->symmetry;
  47         t->root_color = stone_other(color); // to research black moves, root will be white
  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         t->node_sizes -= sizeof(*n); // atomic operation not needed here
  63 }
  64
  65 void
  66 tree_done(struct tree *t)
  67 {
  68         tree_done_node(t, t->root);
  69         if (t->chchvals) free(t->chchvals);
  70         if (t->chvals) free(t->chvals);
  71         free(t);
  72 }
  73
  74
  75 static void
  76 tree_node_dump(struct tree *tree, struct tree_node *node, int l, int thres)
  77 {
  78         for (int i = 0; i < l; i++) fputc(' ', stderr);
  79         int children = 0;
  80         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
  81                 children++;
  82         /* We use 1 as parity, since for all nodes we want to know the
  83          * win probability of _us_, not the node color. */
  84         fprintf(stderr, "[%s] %f %% %d [prior %f %% %d amaf %f %% %d]; hints %x; %d children <%"PRIhash">\n",
  85                 coord2sstr(node->coord, tree->board),
  86                 tree_node_get_value(tree, 1, node->u.value), node->u.playouts,
  87                 tree_node_get_value(tree, 1, node->prior.value), node->prior.playouts,
  88                 tree_node_get_value(tree, 1, node->amaf.value), node->amaf.playouts,
  89                 node->hints, children, node->hash);
  90
  91         /* Print nodes sorted by #playouts. */
  92
  93         struct tree_node *nbox[1000]; int nboxl = 0;
  94         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
  95                 if (ni->u.playouts > thres)
  96                         nbox[nboxl++] = ni;
  97
  98         while (true) {
  99                 int best = -1;
 100                 for (int i = 0; i < nboxl; i++)
 101                         if (nbox[i] && (best < 0 || nbox[i]->u.playouts > nbox[best]->u.playouts))
 102                                 best = i;
 103                 if (best < 0)
 104                         break;
 105                 tree_node_dump(tree, nbox[best], l + 1, /* node->u.value < 0.1 ? 0 : */ thres);
 106                 nbox[best] = NULL;
 107         }
 108 }
 109
 110 void
 111 tree_dump_chval(struct tree *tree, struct move_stats *v)
 112 {
 113         for (int y = board_size(tree->board) - 2; y > 1; y--) {
 114                 for (int x = 1; x < board_size(tree->board) - 1; x++) {
 115                         coord_t c = coord_xy(tree->board, x, y);
 116                         fprintf(stderr, "%.2f%%%05d  ", v[c].value, v[c].playouts);
 117                 }
 118                 fprintf(stderr, "\n");
 119         }
 120 }
 121
 122 void
 123 tree_dump(struct tree *tree, int thres)
 124 {
 125         if (thres && tree->root->u.playouts / thres > 100) {
 126                 /* Be a bit sensible about this; the opening book can create
 127                  * huge dumps at first. */
 128                 thres = tree->root->u.playouts / 100 * (thres < 1000 ? 1 : thres / 1000);
 129         }
 130         fprintf(stderr, "(UCT tree; root %s; extra komi %f)\n",
 131                 stone2str(tree->root_color), tree->extra_komi);
 132         tree_node_dump(tree, tree->root, 0, thres);
 133
 134         if (DEBUGL(3) && tree->chvals) {
 135                 fprintf(stderr, "children stats:\n");
 136                 tree_dump_chval(tree, tree->chvals);
 137                 fprintf(stderr, "grandchildren stats:\n");
 138                 tree_dump_chval(tree, tree->chchvals);
 139         }
 140 }
 141
 142
 143 static char *
 144 tree_book_name(struct board *b)
 145 {
 146         static char buf[256];
 147         if (b->handicap > 0) {
 148                 sprintf(buf, "uctbook-%d-%02.01f-h%d.pachitree", b->size - 2, b->komi, b->handicap);
 149         } else {
 150                 sprintf(buf, "uctbook-%d-%02.01f.pachitree", b->size - 2, b->komi);
 151         }
 152         return buf;
 153 }
 154
 155 static void
 156 tree_node_save(FILE *f, struct tree_node *node, int thres)
 157 {
 158         fputc(1, f);
 159         fwrite(((void *) node) + offsetof(struct tree_node, depth),
 160                sizeof(struct tree_node) - offsetof(struct tree_node, depth),
 161                1, f);
 162
 163         if (node->u.playouts >= thres)
 164                 for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 165                         tree_node_save(f, ni, thres);
 166
 167         fputc(0, f);
 168 }
 169
 170 void
 171 tree_save(struct tree *tree, struct board *b, int thres)
 172 {
 173         char *filename = tree_book_name(b);
 174         FILE *f = fopen(filename, "wb");
 175         if (!f) {
 176                 perror("fopen");
 177                 return;
 178         }
 179         tree_node_save(f, tree->root, thres);
 180         fputc(0, f);
 181         fclose(f);
 182 }
 183
 184
 185 void
 186 tree_node_load(FILE *f, struct tree_node *node, int *num)
 187 {
 188         (*num)++;
 189
 190         fread(((void *) node) + offsetof(struct tree_node, depth),
 191                sizeof(struct tree_node) - offsetof(struct tree_node, depth),
 192                1, f);
 193
 194         /* Keep values in sane scale, otherwise we start overflowing. */
 195 #define MAX_PLAYOUTS    10000000
 196         if (node->u.playouts > MAX_PLAYOUTS) {
 197                 node->u.playouts = MAX_PLAYOUTS;
 198         }
 199         if (node->amaf.playouts > MAX_PLAYOUTS) {
 200                 node->amaf.playouts = MAX_PLAYOUTS;
 201         }
 202 #ifdef ROOT_PARALLEL
 203         // Code needed only for thread_model=root which is much worse
 204         // than treevl. I suggest removing this model entirely.
 205         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 206         memcpy(&node->pu, &node->u, sizeof(node->u));
 207 #endif
 208         struct tree_node *ni = NULL, *ni_prev = NULL;
 209         while (fgetc(f)) {
 210                 ni_prev = ni; ni = calloc(1, sizeof(*ni));
 211                 if (!node->children)
 212                         node->children = ni;
 213                 else
 214                         ni_prev->sibling = ni;
 215                 ni->parent = node;
 216                 tree_node_load(f, ni, num);
 217         }
 218 }
 219
 220 void
 221 tree_load(struct tree *tree, struct board *b)
 222 {
 223         char *filename = tree_book_name(b);
 224         FILE *f = fopen(filename, "rb");
 225         if (!f)
 226                 return;
 227
 228         fprintf(stderr, "Loading opening book %s...\n", filename);
 229
 230         int num = 0;
 231         if (fgetc(f))
 232                 tree_node_load(f, tree->root, &num);
 233         fprintf(stderr, "Loaded %d nodes.\n", num);
 234
 235         fclose(f);
 236 }
 237
 238
 239 static struct tree_node *
 240 tree_node_copy(struct tree_node *node)
 241 {
 242         struct tree_node *n2 = malloc(sizeof(*n2));
 243         *n2 = *node;
 244         if (!node->children)
 245                 return n2;
 246         struct tree_node *ni = node->children;
 247         struct tree_node *ni2 = tree_node_copy(ni);
 248         n2->children = ni2; ni2->parent = n2;
 249         while ((ni = ni->sibling)) {
 250                 ni2->sibling = tree_node_copy(ni);
 251                 ni2 = ni2->sibling; ni2->parent = n2;
 252         }
 253         return n2;
 254 }
 255
 256 struct tree *
 257 tree_copy(struct tree *tree)
 258 {
 259         struct tree *t2 = malloc(sizeof(*t2));
 260         *t2 = *tree;
 261         t2->root = tree_node_copy(tree->root);
 262         return t2;
 263 }
 264
 265 #ifdef ROOT_PARALLEL
 266 static void
 267 tree_node_merge(struct tree_node *dest, struct tree_node *src)
 268 {
 269         /* Do not merge nodes that weren't touched at all. */
 270         assert(dest->pamaf.playouts == src->pamaf.playouts);
 271         assert(dest->pu.playouts == src->pu.playouts);
 272         if (src->amaf.playouts - src->pamaf.playouts == 0
 273             && src->u.playouts - src->pu.playouts == 0) {
 274                 return;
 275         }
 276
 277         dest->hints |= src->hints;
 278
 279         /* Merge the children, both are coord-sorted lists. */
 280         struct tree_node *di = dest->children, **dref = &dest->children;
 281         struct tree_node *si = src->children, **sref = &src->children;
 282         while (di && si) {
 283                 if (di->coord != si->coord) {
 284                         /* src has some extra items or misses di */
 285                         struct tree_node *si2 = si->sibling;
 286                         while (si2 && di->coord != si2->coord) {
 287                                 si2 = si2->sibling;
 288                         }
 289                         if (!si2)
 290                                 goto next_di; /* src misses di, move on */
 291                         /* chain the extra [si,si2) items before di */
 292                         (*dref) = si;
 293                         while (si->sibling != si2) {
 294                                 si->parent = dest;
 295                                 si = si->sibling;
 296                         }
 297                         si->parent = dest;
 298                         si->sibling = di;
 299                         si = si2;
 300                         (*sref) = si;
 301                 }
 302                 /* Matching nodes - recurse... */
 303                 tree_node_merge(di, si);
 304                 /* ...and move on. */
 305                 sref = &si->sibling; si = si->sibling;
 306 next_di:
 307                 dref = &di->sibling; di = di->sibling;
 308         }
 309         if (si) {
 310                 /* Some outstanding nodes are left on src side, rechain
 311                  * them to dst. */
 312                 (*dref) = si;
 313                 while (si) {
 314                         si->parent = dest;
 315                         si = si->sibling;
 316                 }
 317                 (*sref) = NULL;
 318         }
 319
 320         /* Priors should be constant. */
 321         assert(dest->prior.playouts == src->prior.playouts && dest->prior.value == src->prior.value);
 322
 323         stats_merge(&dest->amaf, &src->amaf);
 324         stats_merge(&dest->u, &src->u);
 325 }
 326
 327 /* Merge two trees built upon the same board. Note that the operation is
 328  * destructive on src. */
 329 void
 330 tree_merge(struct tree *dest, struct tree *src)
 331 {
 332         if (src->max_depth > dest->max_depth)
 333                 dest->max_depth = src->max_depth;
 334         tree_node_merge(dest->root, src->root);
 335 }
 336
 337
 338 static void
 339 tree_node_normalize(struct tree_node *node, int factor)
 340 {
 341         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 342                 tree_node_normalize(ni, factor);
 343
 344 #define normalize(s1, s2, t) node->s2.t = node->s1.t + (node->s2.t - node->s1.t) / factor;
 345         normalize(pamaf, amaf, playouts);
 346         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 347
 348         normalize(pu, u, playouts);
 349         memcpy(&node->pu, &node->u, sizeof(node->u));
 350 #undef normalize
 351 }
 352
 353 /* Normalize a tree, dividing the amaf and u values by given
 354  * factor; otherwise, simulations run in independent threads
 355  * two trees built upon the same board. To correctly handle
 356  * results taken from previous simulation run, they are backed
 357  * up in tree. */
 358 void
 359 tree_normalize(struct tree *tree, int factor)
 360 {
 361         tree_node_normalize(tree->root, factor);
 362 }
 363 #endif // ROOT_PARALLEL
 364
 365
 366 /* Get a node of given coordinate from within parent, possibly creating it
 367  * if necessary - in a very raw form (no .d, priors, ...). */
 368 /* FIXME: Adjust for board symmetry. */
 369 struct tree_node *
 370 tree_get_node(struct tree *t, struct tree_node *parent, coord_t c, bool create)
 371 {
 372         if (!parent->children || parent->children->coord >= c) {
 373                 /* Special case: Insertion at the beginning. */
 374                 if (parent->children && parent->children->coord == c)
 375                         return parent->children;
 376                 if (!create)
 377                         return NULL;
 378
 379                 struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 380                 nn->parent = parent; nn->sibling = parent->children;
 381                 parent->children = nn;
 382                 return nn;
 383         }
 384
 385         /* No candidate at the beginning, look through all the children. */
 386
 387         struct tree_node *ni;
 388         for (ni = parent->children; ni->sibling; ni = ni->sibling)
 389                 if (ni->sibling->coord >= c)
 390                         break;
 391
 392         if (ni->sibling && ni->sibling->coord == c)
 393                 return ni->sibling;
 394         assert(ni->coord < c);
 395         if (!create)
 396                 return NULL;
 397
 398         struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 399         nn->parent = parent; nn->sibling = ni->sibling; ni->sibling = nn;
 400         return nn;
 401 }
 402
 403
 404 /* Tree symmetry: When possible, we will localize the tree to a single part
 405  * of the board in tree_expand_node() and possibly flip along symmetry axes
 406  * to another part of the board in tree_promote_at(). We follow b->symmetry
 407  * guidelines here. */
 408
 409
 410 void
 411 tree_expand_node(struct tree *t, struct tree_node *node, struct board *b, enum stone color, struct uct *u, int parity)
 412 {
 413         /* Get a Common Fate Graph distance map from parent node. */
 414         int distances[board_size2(b)];
 415         if (!is_pass(b->last_move.coord) && !is_resign(b->last_move.coord)) {
 416                 cfg_distances(b, node->coord, distances, TREE_NODE_D_MAX);
 417         } else {
 418                 // Pass or resign - everything is too far.
 419                 foreach_point(b) { distances[c] = TREE_NODE_D_MAX + 1; } foreach_point_end;
 420         }
 421
 422         /* Get a map of prior values to initialize the new nodes with. */
 423         struct prior_map map = {
 424                 .b = b,
 425                 .to_play = color,
 426                 .parity = tree_parity(t, parity),
 427                 .distances = distances,
 428         };
 429         // Include pass in the prior map.
 430         struct move_stats map_prior[board_size2(b) + 1]; map.prior = &map_prior[1];
 431         bool map_consider[board_size2(b) + 1]; map.consider = &map_consider[1];
 432         memset(map_prior, 0, sizeof(map_prior));
 433         memset(map_consider, 0, sizeof(map_consider));
 434         struct move pm = { .color = color };
 435         map.consider[pass] = true;
 436         foreach_point(b) {
 437                 if (board_at(b, c) != S_NONE)
 438                         continue;
 439                 pm.coord = c;
 440                 if (!board_is_valid_move(b, &pm))
 441                         continue;
 442                 map.consider[c] = true;
 443         } foreach_point_end;
 444         uct_prior(u, node, &map);
 445
 446         /* Now, create the nodes. */
 447         struct tree_node *ni = tree_init_node(t, pass, node->depth + 1);
 448         struct tree_node *first_child = ni;
 449         ni->parent = node;
 450         ni->prior = map.prior[pass]; ni->d = TREE_NODE_D_MAX + 1;
 451
 452         /* The loop considers only the symmetry playground. */
 453         if (UDEBUGL(6)) {
 454                 fprintf(stderr, "expanding %s within [%d,%d],[%d,%d] %d-%d\n",
 455                                 coord2sstr(node->coord, b),
 456                                 b->symmetry.x1, b->symmetry.y1,
 457                                 b->symmetry.x2, b->symmetry.y2,
 458                                 b->symmetry.type, b->symmetry.d);
 459         }
 460         for (int i = b->symmetry.x1; i <= b->symmetry.x2; i++) {
 461                 for (int j = b->symmetry.y1; j <= b->symmetry.y2; j++) {
 462                         if (b->symmetry.d) {
 463                                 int x = b->symmetry.type == SYM_DIAG_DOWN ? board_size(b) - 1 - i : i;
 464                                 if (x > j) {
 465                                         if (UDEBUGL(7))
 466                                                 fprintf(stderr, "drop %d,%d\n", i, j);
 467                                         continue;
 468                                 }
 469                         }
 470
 471                         coord_t c = coord_xy_otf(i, j, t->board);
 472                         if (!map.consider[c]) // Filter out invalid moves
 473                                 continue;
 474                         assert(c != node->coord); // I have spotted "C3 C3" in some sequence...
 475
 476                         struct tree_node *nj = tree_init_node(t, c, node->depth + 1);
 477                         nj->parent = node; ni->sibling = nj; ni = nj;
 478
 479                         ni->prior = map.prior[c];
 480                         ni->d = distances[c];
 481                 }
 482         }
 483         // Must set children only after everything else is properly initialized
 484         node->children = first_child;
 485 }
 486
 487
 488 static coord_t
 489 flip_coord(struct board *b, coord_t c,
 490            bool flip_horiz, bool flip_vert, int flip_diag)
 491 {
 492         int x = coord_x(c, b), y = coord_y(c, b);
 493         if (flip_diag) {
 494                 int z = x; x = y; y = z;
 495         }
 496         if (flip_horiz) {
 497                 x = board_size(b) - 1 - x;
 498         }
 499         if (flip_vert) {
 500                 y = board_size(b) - 1 - y;
 501         }
 502         return coord_xy_otf(x, y, b);
 503 }
 504
 505 static void
 506 tree_fix_node_symmetry(struct board *b, struct tree_node *node,
 507                        bool flip_horiz, bool flip_vert, int flip_diag)
 508 {
 509         if (!is_pass(node->coord))
 510                 node->coord = flip_coord(b, node->coord, flip_horiz, flip_vert, flip_diag);
 511
 512         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 513                 tree_fix_node_symmetry(b, ni, flip_horiz, flip_vert, flip_diag);
 514 }
 515
 516 static void
 517 tree_fix_symmetry(struct tree *tree, struct board *b, coord_t c)
 518 {
 519         if (is_pass(c))
 520                 return;
 521
 522         struct board_symmetry *s = &tree->root_symmetry;
 523         int cx = coord_x(c, b), cy = coord_y(c, b);
 524
 525         /* playground   X->h->v->d normalization
 526          * :::..        .d...
 527          * .::..        v....
 528          * ..:..        .....
 529          * .....        h...X
 530          * .....        .....  */
 531         bool flip_horiz = cx < s->x1 || cx > s->x2;
 532         bool flip_vert = cy < s->y1 || cy > s->y2;
 533
 534         bool flip_diag = 0;
 535         if (s->d) {
 536                 bool dir = (s->type == SYM_DIAG_DOWN);
 537                 int x = dir ^ flip_horiz ^ flip_vert ? board_size(b) - 1 - cx : cx;
 538                 if (flip_vert ? x < cy : x > cy) {
 539                         flip_diag = 1;
 540                 }
 541         }
 542
 543         if (DEBUGL(4)) {
 544                 fprintf(stderr, "%s [%d,%d -> %d,%d;%d,%d] will flip %d %d %d -> %s, sym %d (%d) -> %d (%d)\n",
 545                         coord2sstr(c, b),
 546                         cx, cy, s->x1, s->y1, s->x2, s->y2,
 547                         flip_horiz, flip_vert, flip_diag,
 548                         coord2sstr(flip_coord(b, c, flip_horiz, flip_vert, flip_diag), b),
 549                         s->type, s->d, b->symmetry.type, b->symmetry.d);
 550         }
 551         if (flip_horiz || flip_vert || flip_diag)
 552                 tree_fix_node_symmetry(b, tree->root, flip_horiz, flip_vert, flip_diag);
 553 }
 554
 555
 556 static void
 557 tree_unlink_node(struct tree_node *node)
 558 {
 559         struct tree_node *ni = node->parent;
 560         if (ni->children == node) {
 561                 ni->children = node->sibling;
 562         } else {
 563                 ni = ni->children;
 564                 while (ni->sibling != node)
 565                         ni = ni->sibling;
 566                 ni->sibling = node->sibling;
 567         }
 568         node->sibling = NULL;
 569         node->parent = NULL;
 570 }
 571
 572 void
 573 tree_delete_node(struct tree *tree, struct tree_node *node)
 574 {
 575         tree_unlink_node(node);
 576         tree_done_node(tree, node);
 577 }
 578
 579 void
 580 tree_promote_node(struct tree *tree, struct tree_node *node)
 581 {
 582         assert(node->parent == tree->root);
 583         tree_unlink_node(node);
 584         tree_done_node(tree, tree->root);
 585         tree->root = node;
 586         tree->root_color = stone_other(tree->root_color);
 587         board_symmetry_update(tree->board, &tree->root_symmetry, node->coord);
 588         tree->max_depth--;
 589         if (tree->chchvals) { free(tree->chchvals); tree->chchvals = NULL; }
 590         if (tree->chvals) { free(tree->chvals); tree->chvals = NULL; }
 591 }
 592
 593 bool
 594 tree_promote_at(struct tree *tree, struct board *b, coord_t c)
 595 {
 596         tree_fix_symmetry(tree, b, c);
 597
 598         for (struct tree_node *ni = tree->root->children; ni; ni = ni->sibling) {
 599                 if (ni->coord == c) {
 600                         tree_promote_node(tree, ni);
 601                         return true;
 602                 }
 603         }
 604         return false;
 605 }