17 #include "uct/internal.h"
18 #include "uct/prior.h"
22 /* Allocate one node in the fast_alloc mode. The returned node
23 * is _not_ initialized. Returns NULL if not enough memory.
24 * This function may be called by multiple threads in parallel. */
25 static struct tree_node
*
26 tree_alloc_node(struct tree
*t
, bool fast_alloc
)
28 struct tree_node
*n
= NULL
;
29 unsigned long old_size
= __sync_fetch_and_add(&t
->nodes_size
, sizeof(*n
));
32 /* The test below works even if max_tree_size is not a
33 * multiple of the node size because tree_init() allocates
34 * space for an extra node. */
35 if (old_size
>= t
->max_tree_size
)
37 assert(t
->nodes
!= NULL
);
38 n
= (struct tree_node
*)(t
->nodes
+ old_size
);
39 memset(n
, 0, sizeof(*n
));
41 n
= calloc2(1, sizeof(*n
));
46 /* Allocate and initialize a node. Returns NULL (fast_alloc mode)
47 * or exits the main program if not enough memory.
48 * This function may be called by multiple threads in parallel. */
49 static struct tree_node
*
50 tree_init_node(struct tree
*t
, coord_t coord
, int depth
, bool fast_alloc
)
53 n
= tree_alloc_node(t
, fast_alloc
);
58 volatile static long c
= 1000000;
59 n
->hash
= __sync_fetch_and_add(&c
, 1);
60 if (depth
> t
->max_depth
)
65 /* Create a tree structure. Pre-allocate all nodes if max_tree_size is > 0. */
67 tree_init(struct board
*board
, enum stone color
, unsigned long max_tree_size
, float ltree_aging
)
69 struct tree
*t
= calloc2(1, sizeof(*t
));
71 t
->max_tree_size
= max_tree_size
;
72 if (max_tree_size
!= 0) {
73 /* Allocate one extra node, max_tree_size may not be multiple of node size. */
74 t
->nodes
= malloc2(max_tree_size
+ sizeof(struct tree_node
));
75 /* The nodes buffer doesn't need initialization. This is currently
76 * done by tree_init_node to spread the load. Doing a memset for the
77 * entire buffer here would be too slow for large trees (>10 GB). */
79 /* The root PASS move is only virtual, we never play it. */
80 t
->root
= tree_init_node(t
, pass
, 0, t
->nodes
);
81 t
->root_symmetry
= board
->symmetry
;
82 t
->root_color
= stone_other(color
); // to research black moves, root will be white
84 t
->ltree_black
= tree_init_node(t
, pass
, 0, false);
85 t
->ltree_white
= tree_init_node(t
, pass
, 0, false);
86 t
->ltree_aging
= ltree_aging
;
91 /* This function may be called by multiple threads in parallel on the
92 * same tree, but not on node n. n may be detached from the tree but
93 * must have been created in this tree originally.
94 * It returns the remaining size of the tree after n has been freed. */
96 tree_done_node(struct tree
*t
, struct tree_node
*n
)
98 struct tree_node
*ni
= n
->children
;
100 struct tree_node
*nj
= ni
->sibling
;
101 tree_done_node(t
, ni
);
105 unsigned long old_size
= __sync_fetch_and_sub(&t
->nodes_size
, sizeof(*n
));
106 return old_size
- sizeof(*n
);
114 /* Worker thread for tree_done_node_detached(). Only for fast_alloc=false. */
116 tree_done_node_worker(void *ctx_
)
118 struct subtree_ctx
*ctx
= ctx_
;
119 char *str
= coord2str(ctx
->n
->coord
, ctx
->t
->board
);
121 unsigned long tree_size
= tree_done_node(ctx
->t
, ctx
->n
);
125 fprintf(stderr
, "done freeing node at %s, tree size %lu\n", str
, tree_size
);
131 /* Asynchronously free the subtree of nodes rooted at n. If the tree becomes
132 * empty free the tree also. Only for fast_alloc=false. */
134 tree_done_node_detached(struct tree
*t
, struct tree_node
*n
)
136 if (n
->u
.playouts
< 1000) { // no thread for small tree
137 if (!tree_done_node(t
, n
))
142 pthread_attr_init(&attr
);
143 pthread_attr_setdetachstate(&attr
, PTHREAD_CREATE_DETACHED
);
146 struct subtree_ctx
*ctx
= malloc2(sizeof(struct subtree_ctx
));
149 pthread_create(&thread
, &attr
, tree_done_node_worker
, ctx
);
150 pthread_attr_destroy(&attr
);
154 tree_done(struct tree
*t
)
156 tree_done_node(t
, t
->ltree_black
);
157 tree_done_node(t
, t
->ltree_white
);
161 } else if (!tree_done_node(t
, t
->root
)) {
163 /* A tree_done_node_worker might still be running on this tree but
164 * it will free the tree later. It is also freeing nodes faster than
165 * we will create new ones. */
171 tree_node_dump(struct tree
*tree
, struct tree_node
*node
, int l
, int thres
)
173 for (int i
= 0; i
< l
; i
++) fputc(' ', stderr
);
175 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
177 /* We use 1 as parity, since for all nodes we want to know the
178 * win probability of _us_, not the node color. */
179 fprintf(stderr
, "[%s] %f %% %d [prior %f %% %d amaf %f %% %d]; hints %x; %d children <%"PRIhash
">\n",
180 coord2sstr(node
->coord
, tree
->board
),
181 tree_node_get_value(tree
, 1, node
->u
.value
), node
->u
.playouts
,
182 tree_node_get_value(tree
, 1, node
->prior
.value
), node
->prior
.playouts
,
183 tree_node_get_value(tree
, 1, node
->amaf
.value
), node
->amaf
.playouts
,
184 node
->hints
, children
, node
->hash
);
186 /* Print nodes sorted by #playouts. */
188 struct tree_node
*nbox
[1000]; int nboxl
= 0;
189 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
190 if (ni
->u
.playouts
> thres
)
195 for (int i
= 0; i
< nboxl
; i
++)
196 if (nbox
[i
] && (best
< 0 || nbox
[i
]->u
.playouts
> nbox
[best
]->u
.playouts
))
200 tree_node_dump(tree
, nbox
[best
], l
+ 1, /* node->u.value < 0.1 ? 0 : */ thres
);
206 tree_dump(struct tree
*tree
, int thres
)
208 if (thres
&& tree
->root
->u
.playouts
/ thres
> 100) {
209 /* Be a bit sensible about this; the opening book can create
210 * huge dumps at first. */
211 thres
= tree
->root
->u
.playouts
/ 100 * (thres
< 1000 ? 1 : thres
/ 1000);
213 fprintf(stderr
, "(UCT tree; root %s; extra komi %f)\n",
214 stone2str(tree
->root_color
), tree
->extra_komi
);
215 tree_node_dump(tree
, tree
->root
, 0, thres
);
217 if (DEBUGL(3) && tree
->ltree_black
) {
218 fprintf(stderr
, "B local tree:\n");
219 tree_node_dump(tree
, tree
->ltree_black
, 0, thres
);
220 fprintf(stderr
, "W local tree:\n");
221 tree_node_dump(tree
, tree
->ltree_white
, 0, thres
);
227 tree_book_name(struct board
*b
)
229 static char buf
[256];
230 if (b
->handicap
> 0) {
231 sprintf(buf
, "uctbook-%d-%02.01f-h%d.pachitree", b
->size
- 2, b
->komi
, b
->handicap
);
233 sprintf(buf
, "uctbook-%d-%02.01f.pachitree", b
->size
- 2, b
->komi
);
239 tree_node_save(FILE *f
, struct tree_node
*node
, int thres
)
241 bool save_children
= node
->u
.playouts
>= thres
;
244 node
->is_expanded
= 0;
247 fwrite(((void *) node
) + offsetof(struct tree_node
, depth
),
248 sizeof(struct tree_node
) - offsetof(struct tree_node
, depth
),
252 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
253 tree_node_save(f
, ni
, thres
);
256 node
->is_expanded
= 1;
263 tree_save(struct tree
*tree
, struct board
*b
, int thres
)
265 char *filename
= tree_book_name(b
);
266 FILE *f
= fopen(filename
, "wb");
271 tree_node_save(f
, tree
->root
, thres
);
278 tree_node_load(FILE *f
, struct tree_node
*node
, int *num
)
282 fread(((void *) node
) + offsetof(struct tree_node
, depth
),
283 sizeof(struct tree_node
) - offsetof(struct tree_node
, depth
),
286 /* Keep values in sane scale, otherwise we start overflowing. */
287 #define MAX_PLAYOUTS 10000000
288 if (node
->u
.playouts
> MAX_PLAYOUTS
) {
289 node
->u
.playouts
= MAX_PLAYOUTS
;
291 if (node
->amaf
.playouts
> MAX_PLAYOUTS
) {
292 node
->amaf
.playouts
= MAX_PLAYOUTS
;
294 memcpy(&node
->pamaf
, &node
->amaf
, sizeof(node
->amaf
));
295 memcpy(&node
->pu
, &node
->u
, sizeof(node
->u
));
297 struct tree_node
*ni
= NULL
, *ni_prev
= NULL
;
299 ni_prev
= ni
; ni
= calloc2(1, sizeof(*ni
));
303 ni_prev
->sibling
= ni
;
305 tree_node_load(f
, ni
, num
);
310 tree_load(struct tree
*tree
, struct board
*b
)
312 char *filename
= tree_book_name(b
);
313 FILE *f
= fopen(filename
, "rb");
317 fprintf(stderr
, "Loading opening book %s...\n", filename
);
321 tree_node_load(f
, tree
->root
, &num
);
322 fprintf(stderr
, "Loaded %d nodes.\n", num
);
328 static struct tree_node
*
329 tree_node_copy(struct tree_node
*node
)
331 struct tree_node
*n2
= malloc2(sizeof(*n2
));
335 struct tree_node
*ni
= node
->children
;
336 struct tree_node
*ni2
= tree_node_copy(ni
);
337 n2
->children
= ni2
; ni2
->parent
= n2
;
338 while ((ni
= ni
->sibling
)) {
339 ni2
->sibling
= tree_node_copy(ni
);
340 ni2
= ni2
->sibling
; ni2
->parent
= n2
;
346 tree_copy(struct tree
*tree
)
348 assert(!tree
->nodes
);
349 struct tree
*t2
= malloc2(sizeof(*t2
));
351 t2
->root
= tree_node_copy(tree
->root
);
355 /* Copy the subtree rooted at node: all nodes at or below depth
356 * or with at least threshold playouts. Only for fast_alloc.
357 * The code is destructive on src. The relative order of children of
358 * a given node is preserved (assumed by tree_get_node in particular).
359 * Returns the copy of node in the destination tree, or NULL
360 * if we could not copy it. */
361 static struct tree_node
*
362 tree_prune(struct tree
*dest
, struct tree
*src
, struct tree_node
*node
,
363 int threshold
, int depth
)
365 assert(dest
->nodes
&& node
);
366 struct tree_node
*n2
= tree_alloc_node(dest
, true);
370 if (n2
->depth
> dest
->max_depth
)
371 dest
->max_depth
= n2
->depth
;
373 n2
->is_expanded
= false;
375 if (node
->depth
>= depth
&& node
->u
.playouts
< threshold
)
377 /* For deep nodes with many playouts, we must copy all children,
378 * even those with zero playouts, because partially expanded
379 * nodes are not supported. Considering them as fully expanded
380 * would degrade the playing strength. The only exception is
381 * when dest becomes full, but this should never happen in practice
382 * if threshold is chosen to limit the number of nodes traversed. */
383 struct tree_node
*ni
= node
->children
;
386 struct tree_node
**prev2
= &(n2
->children
);
388 struct tree_node
*ni2
= tree_prune(dest
, src
, ni
, threshold
, depth
);
391 prev2
= &(ni2
->sibling
);
396 n2
->is_expanded
= true;
398 n2
->children
= NULL
; // avoid partially expanded nodes
403 /* The following constants are used for garbage collection of nodes.
404 * A tree is considered large if the top node has >= 40K playouts.
405 * For such trees, we copy deep nodes only if they have enough
406 * playouts, with a gradually increasing threshold up to 40.
407 * These constants define how much time we're willing to spend
408 * scanning the source tree when promoting a move. The chosen values
409 * make worst case pruning in about 3s for 20 GB ram, and this
410 * is only for long thinking time (>1M playouts). For fast games the
411 * trees don't grow large. For small ram or fast game we copy the
412 * entire tree. These values do not degrade playing strength and are
413 * necessary to avoid losing on time; increasing DEEP_PLAYOUTS_THRESHOLD
414 * or decreasing LARGE_TREE_PLAYOUTS will make the program faster but
416 #define LARGE_TREE_PLAYOUTS 40000LL
417 #define DEEP_PLAYOUTS_THRESHOLD 40
419 /* Garbage collect the tree early if the top node has < 5K playouts,
420 * to avoid having to do it later on a large subtree.
421 * This guarantees garbage collection in < 1s. */
422 #define SMALL_TREE_PLAYOUTS 5000
424 /* Free all the tree, keeping only the subtree rooted at node.
425 * Prune the subtree if necessary to fit in max_size bytes or
426 * to save time scanning the tree.
427 * Returns the moved node. Only for fast_alloc. */
429 tree_garbage_collect(struct tree
*tree
, unsigned long max_size
, struct tree_node
*node
)
431 assert(tree
->nodes
&& !node
->parent
&& !node
->sibling
);
432 double start_time
= time_now();
434 struct tree
*temp_tree
= tree_init(tree
->board
, tree
->root_color
, max_size
, tree
->ltree_aging
);
435 temp_tree
->nodes_size
= 0; // We do not want the dummy pass node
436 struct tree_node
*temp_node
;
438 /* Find the maximum depth at which we can copy all nodes. */
440 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
442 unsigned long nodes_size
= max_nodes
* sizeof(*node
);
443 int max_depth
= node
->depth
;
444 while (nodes_size
< max_size
&& max_nodes
> 1) {
446 nodes_size
+= max_nodes
* nodes_size
;
450 /* Copy all nodes for small trees. For large trees, copy all nodes
451 * with depth <= max_depth, and all nodes with enough playouts.
452 * Avoiding going too deep (except for nodes with many playouts) is mostly
453 * to save time scanning the source tree. It can take over 20s to traverse
454 * completely a large source tree (20 GB) even without copying because
455 * the traversal is not friendly at all with the memory cache. */
456 int threshold
= (node
->u
.playouts
- LARGE_TREE_PLAYOUTS
) * DEEP_PLAYOUTS_THRESHOLD
/ LARGE_TREE_PLAYOUTS
;
457 if (threshold
< 0) threshold
= 0;
458 if (threshold
> DEEP_PLAYOUTS_THRESHOLD
) threshold
= DEEP_PLAYOUTS_THRESHOLD
;
459 temp_node
= tree_prune(temp_tree
, tree
, node
, threshold
, max_depth
);
462 /* Now copy back to original tree. */
463 tree
->nodes_size
= 0;
465 struct tree_node
*new_node
= tree_prune(tree
, temp_tree
, temp_node
, 0, temp_tree
->max_depth
);
468 double now
= time_now();
469 static double prev_time
;
470 if (!prev_time
) prev_time
= start_time
;
472 "tree pruned in %0.6g s, prev %0.3g s ago, dest depth %d wanted %d,"
473 " max_size %lu, pruned size %lu, playouts %d\n",
474 now
- start_time
, start_time
- prev_time
, temp_tree
->max_depth
, max_depth
,
475 max_size
, temp_tree
->nodes_size
, new_node
->u
.playouts
);
476 prev_time
= start_time
;
478 if (temp_tree
->nodes_size
>= temp_tree
->max_tree_size
) {
479 fprintf(stderr
, "temp tree overflow, increase max_tree_size %lu or MIN_FREE_MEM_PERCENT %llu\n",
480 tree
->max_tree_size
, MIN_FREE_MEM_PERCENT
);
482 assert(tree
->nodes_size
== temp_tree
->nodes_size
);
483 assert(tree
->max_depth
== temp_tree
->max_depth
);
485 tree_done(temp_tree
);
491 tree_node_merge(struct tree_node
*dest
, struct tree_node
*src
)
493 /* Do not merge nodes that weren't touched at all. */
494 assert(dest
->pamaf
.playouts
== src
->pamaf
.playouts
);
495 assert(dest
->pu
.playouts
== src
->pu
.playouts
);
496 if (src
->amaf
.playouts
- src
->pamaf
.playouts
== 0
497 && src
->u
.playouts
- src
->pu
.playouts
== 0) {
501 dest
->hints
|= src
->hints
;
503 /* Merge the children, both are coord-sorted lists. */
504 struct tree_node
*di
= dest
->children
, **dref
= &dest
->children
;
505 struct tree_node
*si
= src
->children
, **sref
= &src
->children
;
507 if (di
->coord
!= si
->coord
) {
508 /* src has some extra items or misses di */
509 struct tree_node
*si2
= si
->sibling
;
510 while (si2
&& di
->coord
!= si2
->coord
) {
514 goto next_di
; /* src misses di, move on */
515 /* chain the extra [si,si2) items before di */
517 while (si
->sibling
!= si2
) {
526 /* Matching nodes - recurse... */
527 tree_node_merge(di
, si
);
528 /* ...and move on. */
529 sref
= &si
->sibling
; si
= si
->sibling
;
531 dref
= &di
->sibling
; di
= di
->sibling
;
534 /* Some outstanding nodes are left on src side, rechain
544 /* Priors should be constant. */
545 assert(dest
->prior
.playouts
== src
->prior
.playouts
&& dest
->prior
.value
== src
->prior
.value
);
547 stats_merge(&dest
->amaf
, &src
->amaf
);
548 stats_merge(&dest
->u
, &src
->u
);
551 /* Merge two trees built upon the same board. Note that the operation is
552 * destructive on src. */
554 tree_merge(struct tree
*dest
, struct tree
*src
)
556 if (src
->max_depth
> dest
->max_depth
)
557 dest
->max_depth
= src
->max_depth
;
558 tree_node_merge(dest
->root
, src
->root
);
563 tree_node_normalize(struct tree_node
*node
, int factor
)
565 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
566 tree_node_normalize(ni
, factor
);
568 #define normalize(s1, s2, t) node->s2.t = node->s1.t + (node->s2.t - node->s1.t) / factor;
569 normalize(pamaf
, amaf
, playouts
);
570 memcpy(&node
->pamaf
, &node
->amaf
, sizeof(node
->amaf
));
572 normalize(pu
, u
, playouts
);
573 memcpy(&node
->pu
, &node
->u
, sizeof(node
->u
));
577 /* Normalize a tree, dividing the amaf and u values by given
578 * factor; otherwise, simulations run in independent threads
579 * two trees built upon the same board. To correctly handle
580 * results taken from previous simulation run, they are backed
583 tree_normalize(struct tree
*tree
, int factor
)
585 tree_node_normalize(tree
->root
, factor
);
589 /* Get a node of given coordinate from within parent, possibly creating it
590 * if necessary - in a very raw form (no .d, priors, ...). */
591 /* FIXME: Adjust for board symmetry. */
593 tree_get_node(struct tree
*t
, struct tree_node
*parent
, coord_t c
, bool create
)
595 if (!parent
->children
|| parent
->children
->coord
>= c
) {
596 /* Special case: Insertion at the beginning. */
597 if (parent
->children
&& parent
->children
->coord
== c
)
598 return parent
->children
;
602 struct tree_node
*nn
= tree_init_node(t
, c
, parent
->depth
+ 1, false);
603 nn
->parent
= parent
; nn
->sibling
= parent
->children
;
604 parent
->children
= nn
;
608 /* No candidate at the beginning, look through all the children. */
610 struct tree_node
*ni
;
611 for (ni
= parent
->children
; ni
->sibling
; ni
= ni
->sibling
)
612 if (ni
->sibling
->coord
>= c
)
615 if (ni
->sibling
&& ni
->sibling
->coord
== c
)
617 assert(ni
->coord
< c
);
621 struct tree_node
*nn
= tree_init_node(t
, c
, parent
->depth
+ 1, false);
622 nn
->parent
= parent
; nn
->sibling
= ni
->sibling
; ni
->sibling
= nn
;
626 /* Get local tree node corresponding to given node, given local node child
627 * iterator @lni (which points either at the corresponding node, or at the
628 * nearest local tree node after @ni). */
630 tree_lnode_for_node(struct tree
*tree
, struct tree_node
*ni
, struct tree_node
*lni
, int tenuki_d
)
632 /* Now set up lnode, which is the actual local node
633 * corresponding to ni - either lni if it is an
634 * exact match and ni is not tenuki, <pass> local
635 * node if ni is tenuki, or NULL if there is no
636 * corresponding node available. */
638 if (is_pass(ni
->coord
)) {
639 /* Also, for sanity reasons we never use local
640 * tree for passes. (Maybe we could, but it's
641 * too hard to think about.) */
645 if (lni
->coord
== ni
->coord
) {
646 /* We don't consider tenuki a sequence play
647 * that we have in local tree even though
648 * ni->d is too high; this can happen if this
649 * occured in different board topology. */
653 if (ni
->d
>= tenuki_d
) {
654 /* Tenuki, pick a pass lsibling if available. */
655 assert(lni
->parent
&& lni
->parent
->children
);
656 if (is_pass(lni
->parent
->children
->coord
)) {
657 return lni
->parent
->children
;
663 /* No corresponding local node, lnode stays NULL. */
668 /* Tree symmetry: When possible, we will localize the tree to a single part
669 * of the board in tree_expand_node() and possibly flip along symmetry axes
670 * to another part of the board in tree_promote_at(). We follow b->symmetry
671 * guidelines here. */
674 /* This function must be thread safe, given that board b is only modified by the calling thread. */
676 tree_expand_node(struct tree
*t
, struct tree_node
*node
, struct board
*b
, enum stone color
, struct uct
*u
, int parity
)
678 /* Get a Common Fate Graph distance map from parent node. */
679 int distances
[board_size2(b
)];
680 if (!is_pass(b
->last_move
.coord
) && !is_resign(b
->last_move
.coord
)) {
681 cfg_distances(b
, node
->coord
, distances
, TREE_NODE_D_MAX
);
683 // Pass or resign - everything is too far.
684 foreach_point(b
) { distances
[c
] = TREE_NODE_D_MAX
+ 1; } foreach_point_end
;
687 /* Get a map of prior values to initialize the new nodes with. */
688 struct prior_map map
= {
691 .parity
= tree_parity(t
, parity
),
692 .distances
= distances
,
694 // Include pass in the prior map.
695 struct move_stats map_prior
[board_size2(b
) + 1]; map
.prior
= &map_prior
[1];
696 bool map_consider
[board_size2(b
) + 1]; map
.consider
= &map_consider
[1];
697 memset(map_prior
, 0, sizeof(map_prior
));
698 memset(map_consider
, 0, sizeof(map_consider
));
699 map
.consider
[pass
] = true;
701 if (board_at(b
, c
) != S_NONE
)
703 if (!board_is_valid_play(b
, color
, c
))
705 map
.consider
[c
] = true;
707 uct_prior(u
, node
, &map
);
709 /* Now, create the nodes. */
710 struct tree_node
*ni
= tree_init_node(t
, pass
, node
->depth
+ 1, t
->nodes
);
711 /* In fast_alloc mode we might temporarily run out of nodes but
712 * this should be rare if MIN_FREE_MEM_PERCENT is set correctly. */
714 node
->is_expanded
= false;
717 struct tree_node
*first_child
= ni
;
719 ni
->prior
= map
.prior
[pass
]; ni
->d
= TREE_NODE_D_MAX
+ 1;
721 /* The loop considers only the symmetry playground. */
723 fprintf(stderr
, "expanding %s within [%d,%d],[%d,%d] %d-%d\n",
724 coord2sstr(node
->coord
, b
),
725 b
->symmetry
.x1
, b
->symmetry
.y1
,
726 b
->symmetry
.x2
, b
->symmetry
.y2
,
727 b
->symmetry
.type
, b
->symmetry
.d
);
729 for (int j
= b
->symmetry
.y1
; j
<= b
->symmetry
.y2
; j
++) {
730 for (int i
= b
->symmetry
.x1
; i
<= b
->symmetry
.x2
; i
++) {
732 int x
= b
->symmetry
.type
== SYM_DIAG_DOWN
? board_size(b
) - 1 - i
: i
;
735 fprintf(stderr
, "drop %d,%d\n", i
, j
);
740 coord_t c
= coord_xy(t
->board
, i
, j
);
741 if (!map
.consider
[c
]) // Filter out invalid moves
743 assert(c
!= node
->coord
); // I have spotted "C3 C3" in some sequence...
745 struct tree_node
*nj
= tree_init_node(t
, c
, node
->depth
+ 1, t
->nodes
);
747 node
->is_expanded
= false;
750 nj
->parent
= node
; ni
->sibling
= nj
; ni
= nj
;
752 ni
->prior
= map
.prior
[c
];
753 ni
->d
= distances
[c
];
756 node
->children
= first_child
; // must be done at the end to avoid race
761 flip_coord(struct board
*b
, coord_t c
,
762 bool flip_horiz
, bool flip_vert
, int flip_diag
)
764 int x
= coord_x(c
, b
), y
= coord_y(c
, b
);
766 int z
= x
; x
= y
; y
= z
;
769 x
= board_size(b
) - 1 - x
;
772 y
= board_size(b
) - 1 - y
;
774 return coord_xy(b
, x
, y
);
778 tree_fix_node_symmetry(struct board
*b
, struct tree_node
*node
,
779 bool flip_horiz
, bool flip_vert
, int flip_diag
)
781 if (!is_pass(node
->coord
))
782 node
->coord
= flip_coord(b
, node
->coord
, flip_horiz
, flip_vert
, flip_diag
);
784 for (struct tree_node
*ni
= node
->children
; ni
; ni
= ni
->sibling
)
785 tree_fix_node_symmetry(b
, ni
, flip_horiz
, flip_vert
, flip_diag
);
789 tree_fix_symmetry(struct tree
*tree
, struct board
*b
, coord_t c
)
794 struct board_symmetry
*s
= &tree
->root_symmetry
;
795 int cx
= coord_x(c
, b
), cy
= coord_y(c
, b
);
797 /* playground X->h->v->d normalization
803 bool flip_horiz
= cx
< s
->x1
|| cx
> s
->x2
;
804 bool flip_vert
= cy
< s
->y1
|| cy
> s
->y2
;
808 bool dir
= (s
->type
== SYM_DIAG_DOWN
);
809 int x
= dir
^ flip_horiz
^ flip_vert
? board_size(b
) - 1 - cx
: cx
;
810 if (flip_vert
? x
< cy
: x
> cy
) {
816 fprintf(stderr
, "%s [%d,%d -> %d,%d;%d,%d] will flip %d %d %d -> %s, sym %d (%d) -> %d (%d)\n",
818 cx
, cy
, s
->x1
, s
->y1
, s
->x2
, s
->y2
,
819 flip_horiz
, flip_vert
, flip_diag
,
820 coord2sstr(flip_coord(b
, c
, flip_horiz
, flip_vert
, flip_diag
), b
),
821 s
->type
, s
->d
, b
->symmetry
.type
, b
->symmetry
.d
);
823 if (flip_horiz
|| flip_vert
|| flip_diag
)
824 tree_fix_node_symmetry(b
, tree
->root
, flip_horiz
, flip_vert
, flip_diag
);
829 tree_unlink_node(struct tree_node
*node
)
831 struct tree_node
*ni
= node
->parent
;
832 if (ni
->children
== node
) {
833 ni
->children
= node
->sibling
;
836 while (ni
->sibling
!= node
)
838 ni
->sibling
= node
->sibling
;
840 node
->sibling
= NULL
;
844 /* Reduce weight of statistics on promotion. Remove nodes that
845 * get reduced to zero playouts; returns next node to consider
846 * in the children list (@node may get deleted). */
847 static struct tree_node
*
848 tree_age_node(struct tree
*tree
, struct tree_node
*node
)
850 node
->u
.playouts
/= tree
->ltree_aging
;
851 if (node
->parent
&& !node
->u
.playouts
) {
852 struct tree_node
*sibling
= node
->sibling
;
853 /* Delete node, no playouts. */
854 tree_unlink_node(node
);
855 tree_done_node(tree
, node
);
859 struct tree_node
*ni
= node
->children
;
860 while (ni
) ni
= tree_age_node(tree
, ni
);
861 return node
->sibling
;
864 /* Promotes the given node as the root of the tree. In the fast_alloc
865 * mode, the node may be moved and some of its subtree may be pruned. */
867 tree_promote_node(struct tree
*tree
, struct tree_node
**node
)
869 assert((*node
)->parent
== tree
->root
);
870 tree_unlink_node(*node
);
872 /* Freeing the rest of the tree can take several seconds on large
873 * trees, so we must do it asynchronously: */
874 tree_done_node_detached(tree
, tree
->root
);
876 /* Garbage collect if we run out of memory, or it is cheap to do so now: */
877 unsigned long min_free_size
= (MIN_FREE_MEM_PERCENT
* tree
->max_tree_size
) / 100;
878 if (tree
->nodes_size
>= tree
->max_tree_size
- min_free_size
879 || (tree
->nodes_size
>= min_free_size
&& (*node
)->u
.playouts
< SMALL_TREE_PLAYOUTS
))
880 *node
= tree_garbage_collect(tree
, min_free_size
, *node
);
883 tree
->root_color
= stone_other(tree
->root_color
);
885 board_symmetry_update(tree
->board
, &tree
->root_symmetry
, (*node
)->coord
);
886 /* See tree.score description for explanation on why don't we zero
887 * score on node promotion. */
888 // tree->score.playouts = 0;
890 /* If the tree deepest node was under node, or if we called tree_garbage_collect,
891 * tree->max_depth is correct. Otherwise we could traverse the tree
892 * to recompute max_depth but it's not worth it: it's just for debugging
893 * and soon the tree will grow and max_depth will become correct again. */
895 if (tree
->ltree_aging
!= 1.0f
) { // XXX: != should work here even with the float
896 tree_age_node(tree
, tree
->ltree_black
);
897 tree_age_node(tree
, tree
->ltree_white
);
902 tree_promote_at(struct tree
*tree
, struct board
*b
, coord_t c
)
904 tree_fix_symmetry(tree
, b
, c
);
906 for (struct tree_node
*ni
= tree
->root
->children
; ni
; ni
= ni
->sibling
) {
907 if (ni
->coord
== c
) {
908 tree_promote_node(tree
, &ni
);