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 /* This function may be called by multiple threads in parallel */
  22 static struct tree_node *
  23 tree_init_node(struct tree *t, coord_t coord, int depth)
  24 {
  25         struct tree_node *n = calloc(1, sizeof(*n));
  26         if (!n) {
  27                 fprintf(stderr, "tree_init_node(): OUT OF MEMORY\n");
  28                 exit(1);
  29         }
  30         __sync_fetch_and_add(&t->node_sizes, sizeof(*n));
  31         n->coord = coord;
  32         n->depth = depth;
  33         volatile static long c = 1000000;
  34         n->hash = __sync_fetch_and_add(&c, 1);
  35         if (depth > t->max_depth)
  36                 t->max_depth = depth;
  37         return n;
  38 }
  39
  40 struct tree *
  41 tree_init(struct board *board, enum stone color)
  42 {
  43         struct tree *t = calloc(1, sizeof(*t));
  44         t->board = board;
  45         /* The root PASS move is only virtual, we never play it. */
  46         t->root = tree_init_node(t, pass, 0);
  47         t->root_symmetry = board->symmetry;
  48         t->root_color = stone_other(color); // to research black moves, root will be white
  49         return t;
  50 }
  51
  52
  53 static void
  54 tree_done_node(struct tree *t, struct tree_node *n)
  55 {
  56         struct tree_node *ni = n->children;
  57         while (ni) {
  58                 struct tree_node *nj = ni->sibling;
  59                 tree_done_node(t, ni);
  60                 ni = nj;
  61         }
  62         free(n);
  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
 203         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 204         memcpy(&node->pu, &node->u, sizeof(node->u));
 205
 206         struct tree_node *ni = NULL, *ni_prev = NULL;
 207         while (fgetc(f)) {
 208                 ni_prev = ni; ni = calloc(1, sizeof(*ni));
 209                 if (!node->children)
 210                         node->children = ni;
 211                 else
 212                         ni_prev->sibling = ni;
 213                 ni->parent = node;
 214                 tree_node_load(f, ni, num);
 215         }
 216 }
 217
 218 void
 219 tree_load(struct tree *tree, struct board *b)
 220 {
 221         char *filename = tree_book_name(b);
 222         FILE *f = fopen(filename, "rb");
 223         if (!f)
 224                 return;
 225
 226         fprintf(stderr, "Loading opening book %s...\n", filename);
 227
 228         int num = 0;
 229         if (fgetc(f))
 230                 tree_node_load(f, tree->root, &num);
 231         fprintf(stderr, "Loaded %d nodes.\n", num);
 232
 233         fclose(f);
 234 }
 235
 236
 237 static struct tree_node *
 238 tree_node_copy(struct tree_node *node)
 239 {
 240         struct tree_node *n2 = malloc(sizeof(*n2));
 241         *n2 = *node;
 242         if (!node->children)
 243                 return n2;
 244         struct tree_node *ni = node->children;
 245         struct tree_node *ni2 = tree_node_copy(ni);
 246         n2->children = ni2; ni2->parent = n2;
 247         while ((ni = ni->sibling)) {
 248                 ni2->sibling = tree_node_copy(ni);
 249                 ni2 = ni2->sibling; ni2->parent = n2;
 250         }
 251         return n2;
 252 }
 253
 254 struct tree *
 255 tree_copy(struct tree *tree)
 256 {
 257         struct tree *t2 = malloc(sizeof(*t2));
 258         *t2 = *tree;
 259         t2->root = tree_node_copy(tree->root);
 260         return t2;
 261 }
 262
 263
 264 static void
 265 tree_node_merge(struct tree_node *dest, struct tree_node *src)
 266 {
 267         /* Do not merge nodes that weren't touched at all. */
 268         assert(dest->pamaf.playouts == src->pamaf.playouts);
 269         assert(dest->pu.playouts == src->pu.playouts);
 270         if (src->amaf.playouts - src->pamaf.playouts == 0
 271             && src->u.playouts - src->pu.playouts == 0) {
 272                 return;
 273         }
 274
 275         dest->hints |= src->hints;
 276
 277         /* Merge the children, both are coord-sorted lists. */
 278         struct tree_node *di = dest->children, **dref = &dest->children;
 279         struct tree_node *si = src->children, **sref = &src->children;
 280         while (di && si) {
 281                 if (di->coord != si->coord) {
 282                         /* src has some extra items or misses di */
 283                         struct tree_node *si2 = si->sibling;
 284                         while (si2 && di->coord != si2->coord) {
 285                                 si2 = si2->sibling;
 286                         }
 287                         if (!si2)
 288                                 goto next_di; /* src misses di, move on */
 289                         /* chain the extra [si,si2) items before di */
 290                         (*dref) = si;
 291                         while (si->sibling != si2) {
 292                                 si->parent = dest;
 293                                 si = si->sibling;
 294                         }
 295                         si->parent = dest;
 296                         si->sibling = di;
 297                         si = si2;
 298                         (*sref) = si;
 299                 }
 300                 /* Matching nodes - recurse... */
 301                 tree_node_merge(di, si);
 302                 /* ...and move on. */
 303                 sref = &si->sibling; si = si->sibling;
 304 next_di:
 305                 dref = &di->sibling; di = di->sibling;
 306         }
 307         if (si) {
 308                 /* Some outstanding nodes are left on src side, rechain
 309                  * them to dst. */
 310                 (*dref) = si;
 311                 while (si) {
 312                         si->parent = dest;
 313                         si = si->sibling;
 314                 }
 315                 (*sref) = NULL;
 316         }
 317
 318         /* Priors should be constant. */
 319         assert(dest->prior.playouts == src->prior.playouts && dest->prior.value == src->prior.value);
 320
 321         stats_merge(&dest->amaf, &src->amaf);
 322         stats_merge(&dest->u, &src->u);
 323 }
 324
 325 /* Merge two trees built upon the same board. Note that the operation is
 326  * destructive on src. */
 327 void
 328 tree_merge(struct tree *dest, struct tree *src)
 329 {
 330         if (src->max_depth > dest->max_depth)
 331                 dest->max_depth = src->max_depth;
 332         tree_node_merge(dest->root, src->root);
 333 }
 334
 335
 336 static void
 337 tree_node_normalize(struct tree_node *node, int factor)
 338 {
 339         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 340                 tree_node_normalize(ni, factor);
 341
 342 #define normalize(s1, s2, t) node->s2.t = node->s1.t + (node->s2.t - node->s1.t) / factor;
 343         normalize(pamaf, amaf, playouts);
 344         memcpy(&node->pamaf, &node->amaf, sizeof(node->amaf));
 345
 346         normalize(pu, u, playouts);
 347         memcpy(&node->pu, &node->u, sizeof(node->u));
 348 #undef normalize
 349 }
 350
 351 /* Normalize a tree, dividing the amaf and u values by given
 352  * factor; otherwise, simulations run in independent threads
 353  * two trees built upon the same board. To correctly handle
 354  * results taken from previous simulation run, they are backed
 355  * up in tree. */
 356 void
 357 tree_normalize(struct tree *tree, int factor)
 358 {
 359         tree_node_normalize(tree->root, factor);
 360 }
 361
 362
 363 /* Get a node of given coordinate from within parent, possibly creating it
 364  * if necessary - in a very raw form (no .d, priors, ...). */
 365 /* FIXME: Adjust for board symmetry. */
 366 struct tree_node *
 367 tree_get_node(struct tree *t, struct tree_node *parent, coord_t c, bool create)
 368 {
 369         if (!parent->children || parent->children->coord >= c) {
 370                 /* Special case: Insertion at the beginning. */
 371                 if (parent->children && parent->children->coord == c)
 372                         return parent->children;
 373                 if (!create)
 374                         return NULL;
 375
 376                 struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 377                 nn->parent = parent; nn->sibling = parent->children;
 378                 parent->children = nn;
 379                 return nn;
 380         }
 381
 382         /* No candidate at the beginning, look through all the children. */
 383
 384         struct tree_node *ni;
 385         for (ni = parent->children; ni->sibling; ni = ni->sibling)
 386                 if (ni->sibling->coord >= c)
 387                         break;
 388
 389         if (ni->sibling && ni->sibling->coord == c)
 390                 return ni->sibling;
 391         assert(ni->coord < c);
 392         if (!create)
 393                 return NULL;
 394
 395         struct tree_node *nn = tree_init_node(t, c, parent->depth + 1);
 396         nn->parent = parent; nn->sibling = ni->sibling; ni->sibling = nn;
 397         return nn;
 398 }
 399
 400
 401 /* Tree symmetry: When possible, we will localize the tree to a single part
 402  * of the board in tree_expand_node() and possibly flip along symmetry axes
 403  * to another part of the board in tree_promote_at(). We follow b->symmetry
 404  * guidelines here. */
 405
 406
 407 void
 408 tree_expand_node(struct tree *t, struct tree_node *node, struct board *b, enum stone color, struct uct *u, int parity)
 409 {
 410         /* Get a Common Fate Graph distance map from parent node. */
 411         int distances[board_size2(b)];
 412         if (!is_pass(b->last_move.coord) && !is_resign(b->last_move.coord)) {
 413                 cfg_distances(b, node->coord, distances, TREE_NODE_D_MAX);
 414         } else {
 415                 // Pass or resign - everything is too far.
 416                 foreach_point(b) { distances[c] = TREE_NODE_D_MAX + 1; } foreach_point_end;
 417         }
 418
 419         /* Get a map of prior values to initialize the new nodes with. */
 420         struct prior_map map = {
 421                 .b = b,
 422                 .to_play = color,
 423                 .parity = tree_parity(t, parity),
 424                 .distances = distances,
 425         };
 426         // Include pass in the prior map.
 427         struct move_stats map_prior[board_size2(b) + 1]; map.prior = &map_prior[1];
 428         bool map_consider[board_size2(b) + 1]; map.consider = &map_consider[1];
 429         memset(map_prior, 0, sizeof(map_prior));
 430         memset(map_consider, 0, sizeof(map_consider));
 431         struct move pm = { .color = color };
 432         map.consider[pass] = true;
 433         foreach_point(b) {
 434                 if (board_at(b, c) != S_NONE)
 435                         continue;
 436                 pm.coord = c;
 437                 if (!board_is_valid_move(b, &pm))
 438                         continue;
 439                 map.consider[c] = true;
 440         } foreach_point_end;
 441         uct_prior(u, node, &map);
 442
 443         /* Now, create the nodes. */
 444         struct tree_node *ni = tree_init_node(t, pass, node->depth + 1);
 445         struct tree_node *first_child = ni;
 446         ni->parent = node;
 447         ni->prior = map.prior[pass]; ni->d = TREE_NODE_D_MAX + 1;
 448
 449         /* The loop considers only the symmetry playground. */
 450         if (UDEBUGL(6)) {
 451                 fprintf(stderr, "expanding %s within [%d,%d],[%d,%d] %d-%d\n",
 452                                 coord2sstr(node->coord, b),
 453                                 b->symmetry.x1, b->symmetry.y1,
 454                                 b->symmetry.x2, b->symmetry.y2,
 455                                 b->symmetry.type, b->symmetry.d);
 456         }
 457         for (int i = b->symmetry.x1; i <= b->symmetry.x2; i++) {
 458                 for (int j = b->symmetry.y1; j <= b->symmetry.y2; j++) {
 459                         if (b->symmetry.d) {
 460                                 int x = b->symmetry.type == SYM_DIAG_DOWN ? board_size(b) - 1 - i : i;
 461                                 if (x > j) {
 462                                         if (UDEBUGL(7))
 463                                                 fprintf(stderr, "drop %d,%d\n", i, j);
 464                                         continue;
 465                                 }
 466                         }
 467
 468                         coord_t c = coord_xy_otf(i, j, t->board);
 469                         if (!map.consider[c]) // Filter out invalid moves
 470                                 continue;
 471                         assert(c != node->coord); // I have spotted "C3 C3" in some sequence...
 472
 473                         struct tree_node *nj = tree_init_node(t, c, node->depth + 1);
 474                         nj->parent = node; ni->sibling = nj; ni = nj;
 475
 476                         ni->prior = map.prior[c];
 477                         ni->d = distances[c];
 478                 }
 479         }
 480         node->children = first_child; // must be done at the end to avoid race
 481 }
 482
 483
 484 static coord_t
 485 flip_coord(struct board *b, coord_t c,
 486            bool flip_horiz, bool flip_vert, int flip_diag)
 487 {
 488         int x = coord_x(c, b), y = coord_y(c, b);
 489         if (flip_diag) {
 490                 int z = x; x = y; y = z;
 491         }
 492         if (flip_horiz) {
 493                 x = board_size(b) - 1 - x;
 494         }
 495         if (flip_vert) {
 496                 y = board_size(b) - 1 - y;
 497         }
 498         return coord_xy_otf(x, y, b);
 499 }
 500
 501 static void
 502 tree_fix_node_symmetry(struct board *b, struct tree_node *node,
 503                        bool flip_horiz, bool flip_vert, int flip_diag)
 504 {
 505         if (!is_pass(node->coord))
 506                 node->coord = flip_coord(b, node->coord, flip_horiz, flip_vert, flip_diag);
 507
 508         for (struct tree_node *ni = node->children; ni; ni = ni->sibling)
 509                 tree_fix_node_symmetry(b, ni, flip_horiz, flip_vert, flip_diag);
 510 }
 511
 512 static void
 513 tree_fix_symmetry(struct tree *tree, struct board *b, coord_t c)
 514 {
 515         if (is_pass(c))
 516                 return;
 517
 518         struct board_symmetry *s = &tree->root_symmetry;
 519         int cx = coord_x(c, b), cy = coord_y(c, b);
 520
 521         /* playground   X->h->v->d normalization
 522          * :::..        .d...
 523          * .::..        v....
 524          * ..:..        .....
 525          * .....        h...X
 526          * .....        .....  */
 527         bool flip_horiz = cx < s->x1 || cx > s->x2;
 528         bool flip_vert = cy < s->y1 || cy > s->y2;
 529
 530         bool flip_diag = 0;
 531         if (s->d) {
 532                 bool dir = (s->type == SYM_DIAG_DOWN);
 533                 int x = dir ^ flip_horiz ^ flip_vert ? board_size(b) - 1 - cx : cx;
 534                 if (flip_vert ? x < cy : x > cy) {
 535                         flip_diag = 1;
 536                 }
 537         }
 538
 539         if (DEBUGL(4)) {
 540                 fprintf(stderr, "%s [%d,%d -> %d,%d;%d,%d] will flip %d %d %d -> %s, sym %d (%d) -> %d (%d)\n",
 541                         coord2sstr(c, b),
 542                         cx, cy, s->x1, s->y1, s->x2, s->y2,
 543                         flip_horiz, flip_vert, flip_diag,
 544                         coord2sstr(flip_coord(b, c, flip_horiz, flip_vert, flip_diag), b),
 545                         s->type, s->d, b->symmetry.type, b->symmetry.d);
 546         }
 547         if (flip_horiz || flip_vert || flip_diag)
 548                 tree_fix_node_symmetry(b, tree->root, flip_horiz, flip_vert, flip_diag);
 549 }
 550
 551
 552 static void
 553 tree_unlink_node(struct tree_node *node)
 554 {
 555         struct tree_node *ni = node->parent;
 556         if (ni->children == node) {
 557                 ni->children = node->sibling;
 558         } else {
 559                 ni = ni->children;
 560                 while (ni->sibling != node)
 561                         ni = ni->sibling;
 562                 ni->sibling = node->sibling;
 563         }
 564         node->sibling = NULL;
 565         node->parent = NULL;
 566 }
 567
 568 void
 569 tree_delete_node(struct tree *tree, struct tree_node *node)
 570 {
 571         tree_unlink_node(node);
 572         tree_done_node(tree, node);
 573 }
 574
 575 void
 576 tree_promote_node(struct tree *tree, struct tree_node *node)
 577 {
 578         assert(node->parent == tree->root);
 579         tree_unlink_node(node);
 580         tree_done_node(tree, tree->root);
 581         tree->root = node;
 582         tree->root_color = stone_other(tree->root_color);
 583         board_symmetry_update(tree->board, &tree->root_symmetry, node->coord);
 584         tree->max_depth--;
 585         if (tree->chchvals) { free(tree->chchvals); tree->chchvals = NULL; }
 586         if (tree->chvals) { free(tree->chvals); tree->chvals = NULL; }
 587 }
 588
 589 bool
 590 tree_promote_at(struct tree *tree, struct board *b, coord_t c)
 591 {
 592         tree_fix_symmetry(tree, b, c);
 593
 594         for (struct tree_node *ni = tree->root->children; ni; ni = ni->sibling) {
 595                 if (ni->coord == c) {
 596                         tree_promote_node(tree, ni);
 597                         return true;
 598                 }
 599         }
 600         return false;
 601 }