playout/moggy.c

   1 /* Playout policy by stochastically applying a fixed set of decision
   2  * rules in given order - modelled after the intelligent playouts
   3  * in the Mogo engine. */
   4
   5 #include <assert.h>
   6 #include <math.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9
  10 #define DEBUG
  11 #include "board.h"
  12 #include "debug.h"
  13 #include "mq.h"
  14 #include "pattern3.h"
  15 #include "playout.h"
  16 #include "playout/moggy.h"
  17 #include "random.h"
  18 #include "tactics.h"
  19 #include "uct/prior.h"
  20
  21 #define PLDEBUGL(n) DEBUGL_(p->debug_level, n)
  22
  23 /* Whether to avoid capturing/atariing doomed groups (this is big
  24  * performance hit and may reduce playouts balance; it does increase
  25  * the strength, but not quite proportionally to the performance). */
  26 //#define NO_DOOMED_GROUPS
  27
  28
  29 /* Note that the context can be shared by multiple threads! */
  30
  31 struct moggy_policy {
  32         bool ladders, ladderassess, borderladders, assess_local;
  33         int lcapturerate, atarirate, capturerate, patternrate, korate;
  34         int selfatarirate, alwaysccaprate;
  35         int fillboardtries;
  36         int koage;
  37         /* Whether to look for patterns around second-to-last move. */
  38         bool pattern2;
  39
  40         struct pattern3s patterns;
  41 };
  42
  43
  44 struct group_state {
  45         enum {
  46                 G_ATARI,
  47                 G_2LIB, /* Unused. */
  48                 G_SAFE /* Unused. */
  49         } status:2;
  50
  51         /* Below, we keep track of each trait for each |color_to_play */
  52         int capturable_ready:2; // is @capturable meaningful?
  53         int capturable:2;
  54
  55         int can_countercapture_ready:2;
  56         int can_countercapture:2;
  57 };
  58
  59 /* Cache of evaluation of various board features. */
  60 struct board_state {
  61         int bsize2;
  62         hash_t hash;
  63         struct group_state *groups; /* [board_size2()], indexed by group_t */
  64         unsigned char *groups_known; /* Bitmap of known groups. */
  65 };
  66
  67 /* Using board cache: this turns out to be actually a 10% slowdown,
  68  * since we reuse data in the cache only very little within single
  69  * move. */
  70 // #define CACHE_STATE
  71 /* Reusing board cache across moves if they are successive on the
  72  * board; only cache entries within cfg distance 2 of the last move
  73  * are cleared. */
  74 // #define PERSISTENT_STATE
  75
  76 #ifdef CACHE_STATE
  77 static __thread struct board_state *ss;
  78
  79 static bool
  80 board_state_reuse(struct board_state *s, struct board *b)
  81 {
  82         /* Decide how much of the board state we can reuse. */
  83         /* We do not cache ladder decisions, so we don't have
  84          * to worry about this. */
  85         coord_t c = b->last_move.coord;
  86
  87         if (unlikely(is_pass(c))) {
  88                 /* Passes don't change anything. */
  89                 return true;
  90         }
  91
  92         if (unlikely(board_at(b, c) == S_NONE)) {
  93                 /* Suicide is hopeless. */
  94                 return false;
  95         }
  96
  97         /* XXX: we can make some moves self-atari. */
  98
  99         if (neighbor_count_at(b, c, S_BLACK) + neighbor_count_at(b, c, S_WHITE) == 0) {
 100                 /* We are not taking off liberties of any other stones. */
 101                 return true;
 102         }
 103
 104         return false;
 105 }
 106
 107 static inline struct board_state *
 108 board_state_init(struct board *b)
 109 {
 110         if (ss) {
 111                 if (ss->bsize2 != board_size2(b)) {
 112                         free(ss->groups);
 113                         free(ss->groups_known);
 114                         free(ss); ss = NULL;
 115                 }
 116 #ifdef PERSISTENT_STATE
 117                 /* Only one stone added to the board, nothing removed. */
 118                 else if (ss->hash == (b->hash ^ hash_at(b, b->last_move.coord, b->last_move.color))) {
 119                         ss->hash = b->hash;
 120                         if (likely(board_state_reuse(ss, b)))
 121                                 return ss;
 122                 }
 123 #endif
 124         }
 125         if (!ss) {
 126                 ss = malloc2(sizeof(*ss));
 127                 ss->bsize2 = board_size2(b);
 128                 ss->groups = malloc2(board_size2(b) * sizeof(*ss->groups));
 129                 ss->groups_known = malloc2(board_size2(b) / 8 + 1);
 130         }
 131         ss->hash = b->hash;
 132         memset(ss->groups_known, 0, board_size2(b) / 8 + 1);
 133         return ss;
 134 }
 135
 136 #define group_is_known(s, g) (s->groups_known[g >> 3] & (1 << (g & 7)))
 137 #define group_set_known(s, g) (s->groups_known[g >> 3] |= (1 << (g & 7)))
 138 #define group_trait_ready(s, g, color, gstat, trait) do { \
 139         if (!group_is_known(s, g)) { \
 140                 memset(&s->groups[g], 0, sizeof(s->groups[g])); \
 141                 group_set_known(s, g); \
 142         } \
 143         s->groups[g].status = gstat; \
 144         s->groups[g].trait ## _ready |= color; \
 145 } while (0)
 146 #define group_trait_is_ready(s, g, color, trait) (s->groups[g].trait ## _ready & color)
 147 #define group_trait_set(s, g, color, trait, val) s->groups[g].trait = (s->groups[g].trait & ~color) | (!!val * color)
 148 #define group_trait_get(s, g, color, trait) (s->groups[g].trait & color)
 149
 150 #else
 151
 152 #define board_state_init(b) NULL
 153 #define group_is_known(s, g) false
 154 #define group_set_known(s, g)
 155 #define group_trait_ready(s, g, color, gstat, trait)
 156 #define group_trait_is_ready(s, g, color, trait) false
 157 #define group_trait_set(s, g, color, trait, val)
 158 #define group_trait_get(s, g, color, trait) false
 159 #endif
 160
 161
 162 static char moggy_patterns_src[][11] = {
 163         /* hane pattern - enclosing hane */
 164         "XOX"
 165         "..."
 166         "???",
 167         /* hane pattern - non-cutting hane */
 168         "XO."
 169         "..."
 170         "?.?",
 171         /* hane pattern - magari */
 172         "XO?"
 173         "X.."
 174         "x.?",
 175         /* hane pattern - thin hane */
 176         "XOO"
 177         "..."
 178         "?.?" "X",
 179         /* generic pattern - katatsuke or diagonal attachment; similar to magari */
 180         ".O."
 181         "X.."
 182         "...",
 183         /* cut1 pattern (kiri) - unprotected cut */
 184         "XO?"
 185         "O.o"
 186         "?o?",
 187         /* cut1 pattern (kiri) - peeped cut */
 188         "XO?"
 189         "O.X"
 190         "???",
 191         /* cut2 pattern (de) */
 192         "?X?"
 193         "O.O"
 194         "ooo",
 195         /* cut keima (not in Mogo) */
 196         "OX?"
 197         "o.O"
 198         "???", /* o?? has some pathological tsumego cases */
 199         /* side pattern - chase */
 200         "X.?"
 201         "O.?"
 202         "##?",
 203         /* side pattern - weirdness (SUSPICIOUS) */
 204         "?X?"
 205         "X.O"
 206         "###",
 207         /* side pattern - sagari (SUSPICIOUS) */
 208         "?XO"
 209         "x.x" /* Mogo has "x.?" */
 210         "###" /* Mogo has "X" */,
 211         /* side pattern - throw-in (SUSPICIOUS) */
 212 #if 0
 213         "?OX"
 214         "o.O"
 215         "?##" "X",
 216 #endif
 217         /* side pattern - cut (SUSPICIOUS) */
 218         "?OX"
 219         "X.O"
 220         "###" /* Mogo has "X" */,
 221 };
 222 #define moggy_patterns_src_n sizeof(moggy_patterns_src) / sizeof(moggy_patterns_src[0])
 223
 224 static inline bool
 225 test_pattern3_here(struct playout_policy *p, struct board *b, struct move *m)
 226 {
 227         struct moggy_policy *pp = p->data;
 228         /* Check if 3x3 pattern is matched by given move... */
 229         if (!pattern3_move_here(&pp->patterns, b, m))
 230                 return false;
 231         /* ...and the move is not obviously stupid. */
 232         if (is_bad_selfatari(b, m->color, m->coord))
 233                 return false;
 234         /* Ladder moves are stupid. */
 235         group_t atari_neighbor = board_get_atari_neighbor(b, m->coord, m->color);
 236         if (atari_neighbor && is_ladder(b, m->coord, atari_neighbor, pp->borderladders, pp->ladders))
 237                 return false;
 238         return true;
 239 }
 240
 241 static void
 242 apply_pattern_here(struct playout_policy *p, struct board *b, coord_t c, enum stone color, struct move_queue *q)
 243 {
 244         struct move m2 = { .coord = c, .color = color };
 245         if (board_is_valid_move(b, &m2) && test_pattern3_here(p, b, &m2))
 246                 mq_add(q, c);
 247 }
 248
 249 /* Check if we match any pattern around given move (with the other color to play). */
 250 static coord_t
 251 apply_pattern(struct playout_policy *p, struct board *b, struct move *m, struct move *mm)
 252 {
 253         struct move_queue q;
 254         q.moves = 0;
 255
 256         /* Suicides do not make any patterns and confuse us. */
 257         if (board_at(b, m->coord) == S_NONE || board_at(b, m->coord) == S_OFFBOARD)
 258                 return pass;
 259
 260         foreach_8neighbor(b, m->coord) {
 261                 apply_pattern_here(p, b, c, stone_other(m->color), &q);
 262         } foreach_8neighbor_end;
 263
 264         if (mm) { /* Second move for pattern searching */
 265                 foreach_8neighbor(b, mm->coord) {
 266                         if (coord_is_8adjecent(m->coord, c, b))
 267                                 continue;
 268                         apply_pattern_here(p, b, c, stone_other(m->color), &q);
 269                 } foreach_8neighbor_end;
 270         }
 271
 272         if (PLDEBUGL(5))
 273                 mq_print(&q, b, "Pattern");
 274
 275         return mq_pick(&q);
 276 }
 277
 278
 279 static bool
 280 can_play_on_lib(struct playout_policy *p, struct board_state *s,
 281                 struct board *b, group_t g, enum stone to_play)
 282 {
 283         if (group_is_known(s, g) && group_trait_is_ready(s, g, to_play, capturable)) {
 284                 /* We have already seen this group. */
 285                 assert(s->groups[g].status == G_ATARI);
 286                 if (group_trait_get(s, g, to_play, capturable))
 287                         return true;
 288                 else
 289                         return false;
 290         }
 291
 292         /* Cache miss. Set up cache entry, default at capturable = false. */
 293         group_trait_ready(s, g, to_play, G_ATARI, capturable);
 294
 295         coord_t capture = board_group_info(b, g).lib[0];
 296         if (PLDEBUGL(6))
 297                 fprintf(stderr, "can capture group %d (%s)?\n",
 298                         g, coord2sstr(capture, b));
 299         /* Does playing on the liberty usefully capture the group? */
 300         if (board_is_valid_play(b, to_play, capture)
 301             && !is_bad_selfatari(b, to_play, capture)) {
 302                 group_trait_set(s, g, to_play, capturable, true);
 303                 return true;
 304         }
 305
 306         return false;
 307 }
 308
 309 /* For given position @c, decide if this is a group that is in danger from
 310  * @capturer and @to_play can do anything about it (play at the last
 311  * liberty to either capture or escape). */
 312 /* Note that @to_play is important; e.g. consider snapback, it's good
 313  * to play at the last liberty by attacker, but not defender. */
 314 static __attribute__((always_inline)) bool
 315 capturable_group(struct playout_policy *p, struct board_state *s,
 316                  struct board *b, enum stone capturer, coord_t c,
 317                  enum stone to_play)
 318 {
 319         group_t g = group_at(b, c);
 320         if (likely(board_at(b, c) != stone_other(capturer)
 321                    || board_group_info(b, g).libs > 1))
 322                 return false;
 323
 324         return can_play_on_lib(p, s, b, g, to_play);
 325 }
 326
 327 /* For given atari group @group owned by @owner, decide if @to_play
 328  * can save it / keep it in danger by dealing with one of the
 329  * neighboring groups. */
 330 static bool
 331 can_countercapture(struct playout_policy *p, struct board_state *s,
 332                    struct board *b, enum stone owner, group_t g,
 333                    enum stone to_play, struct move_queue *q)
 334 {
 335         if (b->clen < 2)
 336                 return false;
 337         if (group_is_known(s, g) && group_trait_is_ready(s, g, to_play, can_countercapture)) {
 338                 /* We have already seen this group. */
 339                 assert(s->groups[g].status == G_ATARI);
 340                 if (group_trait_get(s, g, to_play, can_countercapture)) {
 341                         if (q) { /* Scan for countercapture liberties. */
 342                                 goto scan;
 343                         }
 344                         return true;
 345                 } else {
 346                         return false;
 347                 }
 348         }
 349
 350         /* Cache miss. Set up cache entry, default at can_countercapture = true. */
 351         group_trait_ready(s, g, to_play, G_ATARI, can_countercapture);
 352         group_trait_set(s, g, to_play, can_countercapture, true);
 353
 354 scan:;
 355         int qmoves_prev = q ? q->moves : 0;
 356
 357         foreach_in_group(b, g) {
 358                 foreach_neighbor(b, c, {
 359                         if (!capturable_group(p, s, b, owner, c, to_play))
 360                                 continue;
 361
 362                         if (!q) {
 363                                 return true;
 364                         }
 365                         mq_add(q, board_group_info(b, group_at(b, c)).lib[0]);
 366                         mq_nodup(q);
 367                 });
 368         } foreach_in_group_end;
 369
 370         bool can = q ? q->moves > qmoves_prev : false;
 371         group_trait_set(s, g, to_play, can_countercapture, can);
 372         return can;
 373 }
 374
 375 #ifdef NO_DOOMED_GROUPS
 376 static bool
 377 can_be_rescued(struct playout_policy *p, struct board_state *s,
 378                struct board *b, group_t group, enum stone color)
 379 {
 380         /* Does playing on the liberty rescue the group? */
 381         if (can_play_on_lib(p, s, b, group, color))
 382                 return true;
 383
 384         /* Then, maybe we can capture one of our neighbors? */
 385         return can_countercapture(p, s, b, color, group, color, NULL);
 386 }
 387 #endif
 388
 389 /* ladder != NULL implies to always enqueue all relevant moves. */
 390 static void
 391 group_atari_check(struct playout_policy *p, struct board *b, group_t group, enum stone to_play,
 392                   struct move_queue *q, coord_t *ladder, struct board_state *s)
 393 {
 394         struct moggy_policy *pp = p->data;
 395         int qmoves_prev = q->moves;
 396
 397         /* We don't use @to_play almost anywhere since any moves here are good
 398          * for both defender and attacker. */
 399
 400         enum stone color = board_at(b, group_base(group));
 401         coord_t lib = board_group_info(b, group).lib[0];
 402
 403         assert(color != S_OFFBOARD && color != S_NONE);
 404         if (PLDEBUGL(5))
 405                 fprintf(stderr, "[%s] atariiiiiiiii %s of color %d\n",
 406                         coord2sstr(group, b), coord2sstr(lib, b), color);
 407         assert(board_at(b, lib) == S_NONE);
 408
 409         /* Do not bother with kos. */
 410         if (group_is_onestone(b, group)
 411             && neighbor_count_at(b, lib, color) + neighbor_count_at(b, lib, S_OFFBOARD) == 4)
 412                 return;
 413
 414         /* Can we capture some neighbor? */
 415         bool ccap = can_countercapture(p, s, b, color, group, to_play, q);
 416         if (ccap && !ladder && pp->alwaysccaprate > fast_random(100))
 417                 return;
 418
 419         /* Do not suicide... */
 420         if (!can_play_on_lib(p, s, b, group, to_play))
 421                 return;
 422 #ifdef NO_DOOMED_GROUPS
 423         /* Do not remove group that cannot be saved by the opponent. */
 424         if (to_play != color && !can_be_rescued(p, s, b, group, color))
 425                 return;
 426 #endif
 427         if (PLDEBUGL(6))
 428                 fprintf(stderr, "...escape route valid\n");
 429
 430         /* ...or play out ladders. */
 431         if (is_ladder(b, lib, group, pp->borderladders, pp->ladders)) {
 432                 /* Sometimes we want to keep the ladder move in the
 433                  * queue in order to discourage it. */
 434                 if (!ladder)
 435                         return;
 436                 else
 437                         *ladder = lib;
 438         }
 439         if (PLDEBUGL(6))
 440                 fprintf(stderr, "...no ladder\n");
 441
 442         if (to_play != color) {
 443                 /* We are the attacker! In that case, throw away the moves
 444                  * that defend our groups, since we can capture the culprit. */
 445                 q->moves = qmoves_prev;
 446         }
 447
 448         mq_add(q, lib);
 449         mq_nodup(q);
 450 }
 451
 452 static coord_t
 453 global_atari_check(struct playout_policy *p, struct board *b, enum stone to_play, struct board_state *s)
 454 {
 455         struct move_queue q;
 456         q.moves = 0;
 457
 458         if (b->clen == 0)
 459                 return pass;
 460
 461         int g_base = fast_random(b->clen);
 462         for (int g = g_base; g < b->clen; g++) {
 463                 group_atari_check(p, b, group_at(b, group_base(b->c[g])), to_play, &q, NULL, s);
 464                 if (q.moves > 0)
 465                         return mq_pick(&q);
 466         }
 467         for (int g = 0; g < g_base; g++) {
 468                 group_atari_check(p, b, group_at(b, group_base(b->c[g])), to_play, &q, NULL, s);
 469                 if (q.moves > 0)
 470                         return mq_pick(&q);
 471         }
 472         return pass;
 473 }
 474
 475 static coord_t
 476 local_atari_check(struct playout_policy *p, struct board *b, struct move *m, struct board_state *s)
 477 {
 478         struct move_queue q;
 479         q.moves = 0;
 480
 481         /* Did the opponent play a self-atari? */
 482         if (board_group_info(b, group_at(b, m->coord)).libs == 1) {
 483                 group_atari_check(p, b, group_at(b, m->coord), stone_other(m->color), &q, NULL, s);
 484         }
 485
 486         foreach_neighbor(b, m->coord, {
 487                 group_t g = group_at(b, c);
 488                 if (!g || board_group_info(b, g).libs != 1)
 489                         continue;
 490                 group_atari_check(p, b, g, stone_other(m->color), &q, NULL, s);
 491         });
 492
 493         if (PLDEBUGL(5))
 494                 mq_print(&q, b, "Local atari");
 495
 496         return mq_pick(&q);
 497 }
 498
 499 static bool
 500 miai_2lib(struct board *b, group_t group, enum stone color)
 501 {
 502         bool can_connect = false, can_pull_out = false;
 503         /* We have miai if we can either connect on both libs,
 504          * or connect on one lib and escape on another. (Just
 505          * having two escape routes can be risky.) We must make
 506          * sure that we don't consider following as miai:
 507          * X X X O
 508          * X . . O
 509          * O O X O - left dot would be pull-out, right dot connect */
 510         foreach_neighbor(b, board_group_info(b, group).lib[0], {
 511                 enum stone cc = board_at(b, c);
 512                 if (cc == S_NONE && cc != board_group_info(b, group).lib[1]) {
 513                         can_pull_out = true;
 514                 } else if (cc != color) {
 515                         continue;
 516                 }
 517
 518                 group_t cg = group_at(b, c);
 519                 if (cg && cg != group && board_group_info(b, cg).libs > 1)
 520                         can_connect = true;
 521         });
 522         foreach_neighbor(b, board_group_info(b, group).lib[1], {
 523                 enum stone cc = board_at(b, c);
 524                 if (c == board_group_info(b, group).lib[0])
 525                         continue;
 526                 if (cc == S_NONE && can_connect) {
 527                         return true;
 528                 } else if (cc != color) {
 529                         continue;
 530                 }
 531
 532                 group_t cg = group_at(b, c);
 533                 if (cg && cg != group && board_group_info(b, cg).libs > 1)
 534                         return (can_connect || can_pull_out);
 535         });
 536         return false;
 537 }
 538
 539 static void
 540 check_group_atari(struct board *b, group_t group, enum stone owner,
 541                   enum stone to_play, struct move_queue *q)
 542 {
 543         for (int i = 0; i < 2; i++) {
 544                 coord_t lib = board_group_info(b, group).lib[i];
 545                 assert(board_at(b, lib) == S_NONE);
 546                 if (!board_is_valid_play(b, to_play, lib))
 547                         continue;
 548
 549                 /* Don't play at the spot if it is extremely short
 550                  * of liberties... */
 551                 /* XXX: This looks harmful, could significantly
 552                  * prefer atari to throwin:
 553                  *
 554                  * XXXOOOOOXX
 555                  * .OO.....OX
 556                  * XXXOOOOOOX */
 557 #if 0
 558                 if (neighbor_count_at(b, lib, stone_other(owner)) + immediate_liberty_count(b, lib) < 2)
 559                         continue;
 560 #endif
 561
 562 #ifdef NO_DOOMED_GROUPS
 563                 /* If the owner can't play at the spot, we don't want
 564                  * to bother either. */
 565                 if (is_bad_selfatari(b, owner, lib))
 566                         continue;
 567 #endif
 568
 569                 /* Of course we don't want to play bad selfatari
 570                  * ourselves, if we are the attacker... */
 571                 if (
 572 #ifdef NO_DOOMED_GROUPS
 573                     to_play != owner &&
 574 #endif
 575                     is_bad_selfatari(b, to_play, lib))
 576                         continue;
 577
 578                 /* Tasty! Crispy! Good! */
 579                 mq_add(q, lib);
 580                 mq_nodup(q);
 581         }
 582 }
 583
 584 static void
 585 group_2lib_check(struct playout_policy *p, struct board *b, group_t group, enum stone to_play,
 586                  struct move_queue *q, struct board_state *s)
 587 {
 588         enum stone color = board_at(b, group_base(group));
 589         assert(color != S_OFFBOARD && color != S_NONE);
 590
 591         if (PLDEBUGL(5))
 592                 fprintf(stderr, "[%s] 2lib check of color %d\n",
 593                         coord2sstr(group, b), color);
 594
 595         /* Do not try to atari groups that cannot be harmed. */
 596         if (miai_2lib(b, group, color))
 597                 return;
 598
 599         check_group_atari(b, group, color, to_play, q);
 600
 601         /* Can we counter-atari another group, if we are the defender? */
 602         if (to_play != color)
 603                 return;
 604         foreach_in_group(b, group) {
 605                 foreach_neighbor(b, c, {
 606                         if (board_at(b, c) != stone_other(color))
 607                                 continue;
 608                         group_t g2 = group_at(b, c);
 609                         if (board_group_info(b, g2).libs != 2)
 610                                 continue;
 611                         check_group_atari(b, g2, color, to_play, q);
 612                 });
 613         } foreach_in_group_end;
 614 }
 615
 616 static coord_t
 617 local_2lib_check(struct playout_policy *p, struct board *b, struct move *m, struct board_state *s)
 618 {
 619         struct move_queue q;
 620         q.moves = 0;
 621
 622         /* Does the opponent have just two liberties? */
 623         if (board_group_info(b, group_at(b, m->coord)).libs == 2) {
 624                 group_2lib_check(p, b, group_at(b, m->coord), stone_other(m->color), &q, s);
 625 #if 0
 626                 /* We always prefer to take off an enemy chain liberty
 627                  * before pulling out ourselves. */
 628                 /* XXX: We aren't guaranteed to return to that group
 629                  * later. */
 630                 if (q.moves)
 631                         return q.move[fast_random(q.moves)];
 632 #endif
 633         }
 634
 635         /* Then he took a third liberty from neighboring chain? */
 636         foreach_neighbor(b, m->coord, {
 637                 group_t g = group_at(b, c);
 638                 if (!g || board_group_info(b, g).libs != 2)
 639                         continue;
 640                 group_2lib_check(p, b, g, stone_other(m->color), &q, s);
 641         });
 642
 643         if (PLDEBUGL(5))
 644                 mq_print(&q, b, "Local 2lib");
 645
 646         return mq_pick(&q);
 647 }
 648
 649 coord_t
 650 playout_moggy_choose(struct playout_policy *p, struct board *b, enum stone to_play)
 651 {
 652         struct moggy_policy *pp = p->data;
 653         coord_t c;
 654
 655         struct board_state *s = board_state_init(b);
 656
 657         if (PLDEBUGL(5))
 658                 board_print(b, stderr);
 659
 660         /* Ko fight check */
 661         if (!is_pass(b->last_ko.coord) && is_pass(b->ko.coord)
 662             && b->moves - b->last_ko_age < pp->koage
 663             && pp->korate > fast_random(100)) {
 664                 if (board_is_valid_play(b, to_play, b->last_ko.coord)
 665                     && !is_bad_selfatari(b, to_play, b->last_ko.coord))
 666                         return b->last_ko.coord;
 667         }
 668
 669         /* Local checks */
 670         if (!is_pass(b->last_move.coord)) {
 671                 /* Local group in atari? */
 672                 if (pp->lcapturerate > fast_random(100)) {
 673                         c = local_atari_check(p, b, &b->last_move, s);
 674                         if (!is_pass(c))
 675                                 return c;
 676                 }
 677
 678                 /* Local group can be PUT in atari? */
 679                 if (pp->atarirate > fast_random(100)) {
 680                         c = local_2lib_check(p, b, &b->last_move, s);
 681                         if (!is_pass(c))
 682                                 return c;
 683                 }
 684
 685                 /* Check for patterns we know */
 686                 if (pp->patternrate > fast_random(100)) {
 687                         c = apply_pattern(p, b, &b->last_move,
 688                                           pp->pattern2 && b->last_move2.coord >= 0 ? &b->last_move2 : NULL);
 689                         if (!is_pass(c))
 690                                 return c;
 691                 }
 692         }
 693
 694         /* Global checks */
 695
 696         /* Any groups in atari? */
 697         if (pp->capturerate > fast_random(100)) {
 698                 c = global_atari_check(p, b, to_play, s);
 699                 if (!is_pass(c))
 700                         return c;
 701         }
 702
 703         /* Fill board */
 704         int fbtries = b->flen / 8;
 705         for (int i = 0; i < (fbtries < pp->fillboardtries ? fbtries : pp->fillboardtries); i++) {
 706                 coord_t coord = b->f[fast_random(b->flen)];
 707                 if (is_pass(coord) || immediate_liberty_count(b, coord) != 4)
 708                         continue;
 709                 foreach_diag_neighbor(b, coord) {
 710                         if (board_at(b, c) != S_NONE)
 711                                 goto next_try;
 712                 } foreach_diag_neighbor_end;
 713                 return coord;
 714 next_try:;
 715         }
 716
 717         return pass;
 718 }
 719
 720
 721 static int
 722 assess_local_bonus(struct playout_policy *p, struct board *board, coord_t a, coord_t b, int games)
 723 {
 724         struct moggy_policy *pp = p->data;
 725         if (!pp->assess_local)
 726                 return games;
 727
 728         int dx = abs(coord_x(a, board) - coord_x(b, board));
 729         int dy = abs(coord_y(a, board) - coord_y(b, board));
 730         /* adjecent move, directly or diagonally? */
 731         if (dx + dy <= 1 + (dx && dy))
 732                 return games;
 733         else
 734                 return games / 2;
 735 }
 736
 737 void
 738 playout_moggy_assess_group(struct playout_policy *p, struct prior_map *map, group_t g, int games,
 739                            struct board_state *s)
 740 {
 741         struct moggy_policy *pp = p->data;
 742         struct board *b = map->b;
 743         struct move_queue q; q.moves = 0;
 744
 745         if (board_group_info(b, g).libs > 2)
 746                 return;
 747
 748         if (PLDEBUGL(5)) {
 749                 fprintf(stderr, "ASSESS of group %s:\n", coord2sstr(g, b));
 750                 board_print(b, stderr);
 751         }
 752
 753         if (board_group_info(b, g).libs == 2) {
 754                 if (!pp->atarirate)
 755                         return;
 756                 group_2lib_check(p, b, g, map->to_play, &q, s);
 757                 while (q.moves--) {
 758                         coord_t coord = q.move[q.moves];
 759                         if (PLDEBUGL(5))
 760                                 fprintf(stderr, "1.0: 2lib %s\n", coord2sstr(coord, b));
 761                         int assess = assess_local_bonus(p, b, b->last_move.coord, coord, games) / 2;
 762                         add_prior_value(map, coord, 1, assess);
 763                 }
 764                 return;
 765         }
 766
 767         /* This group, sir, is in atari! */
 768
 769         if (!pp->capturerate && !pp->lcapturerate && !pp->ladderassess)
 770                 return;
 771
 772         coord_t ladder = pass;
 773         group_atari_check(p, b, g, map->to_play, &q, &ladder, s);
 774         while (q.moves--) {
 775                 coord_t coord = q.move[q.moves];
 776
 777                 /* _Never_ play here if this move plays out
 778                  * a caught ladder. */
 779                 if (coord == ladder && !board_playing_ko_threat(b)) {
 780                         /* Note that the opposite is not guarded against;
 781                          * we do not advise against capturing a laddered
 782                          * group (but we don't encourage it either). Such
 783                          * a move can simplify tactical situations if we
 784                          * can afford it. */
 785                         if (!pp->ladderassess || map->to_play != board_at(b, g))
 786                                 continue;
 787                         /* FIXME: We give the malus even if this move
 788                          * captures another group. */
 789                         if (PLDEBUGL(5))
 790                                 fprintf(stderr, "0.0: ladder %s\n", coord2sstr(coord, b));
 791                         add_prior_value(map, coord, 0, games);
 792                         continue;
 793                 }
 794
 795                 if (!pp->capturerate && !pp->lcapturerate)
 796                         continue;
 797
 798                 if (PLDEBUGL(5))
 799                         fprintf(stderr, "1.0: atari %s\n", coord2sstr(coord, b));
 800                 int assess = assess_local_bonus(p, b, b->last_move.coord, coord, games) * 2;
 801                 add_prior_value(map, coord, 1, assess);
 802         }
 803 }
 804
 805 void
 806 playout_moggy_assess_one(struct playout_policy *p, struct prior_map *map, coord_t coord, int games)
 807 {
 808         struct moggy_policy *pp = p->data;
 809         struct board *b = map->b;
 810
 811         if (PLDEBUGL(5)) {
 812                 fprintf(stderr, "ASSESS of move %s:\n", coord2sstr(coord, b));
 813                 board_print(b, stderr);
 814         }
 815
 816         /* Is this move a self-atari? */
 817         if (pp->selfatarirate) {
 818                 if (!board_playing_ko_threat(b) && is_bad_selfatari(b, map->to_play, coord)) {
 819                         if (PLDEBUGL(5))
 820                                 fprintf(stderr, "0.0: self-atari\n");
 821                         add_prior_value(map, coord, 0, games);
 822                         return;
 823                 }
 824         }
 825
 826         /* Pattern check */
 827         if (pp->patternrate) {
 828                 struct move m = { .color = map->to_play, .coord = coord };
 829                 if (test_pattern3_here(p, b, &m)) {
 830                         if (PLDEBUGL(5))
 831                                 fprintf(stderr, "1.0: pattern\n");
 832                         int assess = assess_local_bonus(p, b, b->last_move.coord, coord, games);
 833                         add_prior_value(map, coord, 1, assess);
 834                 }
 835         }
 836
 837         return;
 838 }
 839
 840 void
 841 playout_moggy_assess(struct playout_policy *p, struct prior_map *map, int games)
 842 {
 843         struct moggy_policy *pp = p->data;
 844
 845         struct board_state *s = board_state_init(map->b);
 846
 847         /* First, go through all endangered groups. */
 848         if (pp->lcapturerate || pp->capturerate || pp->atarirate || pp->ladderassess)
 849                 for (group_t g = 1; g < board_size2(map->b); g++)
 850                         if (group_at(map->b, g) == g)
 851                                 playout_moggy_assess_group(p, map, g, games, s);
 852
 853         /* Then, assess individual moves. */
 854         if (!pp->patternrate && !pp->selfatarirate)
 855                 return;
 856         foreach_point(map->b) {
 857                 if (map->consider[c])
 858                         playout_moggy_assess_one(p, map, c, games);
 859         } foreach_point_end;
 860 }
 861
 862 bool
 863 playout_moggy_permit(struct playout_policy *p, struct board *b, struct move *m)
 864 {
 865         struct moggy_policy *pp = p->data;
 866
 867         /* The idea is simple for now - never allow self-atari moves.
 868          * They suck in general, but this also permits us to actually
 869          * handle seki in the playout stage. */
 870
 871         if (fast_random(100) >= pp->selfatarirate) {
 872                 if (PLDEBUGL(5))
 873                         fprintf(stderr, "skipping sar test\n");
 874                 return true;
 875         }
 876         bool selfatari = is_bad_selfatari(b, m->color, m->coord);
 877         if (PLDEBUGL(5) && selfatari)
 878                 fprintf(stderr, "__ Prohibiting self-atari %s %s\n",
 879                         stone2str(m->color), coord2sstr(m->coord, b));
 880         return !selfatari;
 881 }
 882
 883
 884 struct playout_policy *
 885 playout_moggy_init(char *arg, struct board *b)
 886 {
 887         struct playout_policy *p = calloc2(1, sizeof(*p));
 888         struct moggy_policy *pp = calloc2(1, sizeof(*pp));
 889         p->data = pp;
 890         p->choose = playout_moggy_choose;
 891         p->assess = playout_moggy_assess;
 892         p->permit = playout_moggy_permit;
 893
 894         int rate = 90;
 895
 896         pp->lcapturerate = pp->atarirate = pp->capturerate = pp->patternrate = pp->selfatarirate
 897                         = -1;
 898         pp->korate = 0; pp->koage = 4;
 899         pp->alwaysccaprate = 0;
 900         pp->ladders = pp->borderladders = true;
 901         pp->ladderassess = true;
 902
 903         if (arg) {
 904                 char *optspec, *next = arg;
 905                 while (*next) {
 906                         optspec = next;
 907                         next += strcspn(next, ":");
 908                         if (*next) { *next++ = 0; } else { *next = 0; }
 909
 910                         char *optname = optspec;
 911                         char *optval = strchr(optspec, '=');
 912                         if (optval) *optval++ = 0;
 913
 914                         if (!strcasecmp(optname, "lcapturerate") && optval) {
 915                                 pp->lcapturerate = atoi(optval);
 916                         } else if (!strcasecmp(optname, "atarirate") && optval) {
 917                                 pp->atarirate = atoi(optval);
 918                         } else if (!strcasecmp(optname, "capturerate") && optval) {
 919                                 pp->capturerate = atoi(optval);
 920                         } else if (!strcasecmp(optname, "patternrate") && optval) {
 921                                 pp->patternrate = atoi(optval);
 922                         } else if (!strcasecmp(optname, "selfatarirate") && optval) {
 923                                 pp->selfatarirate = atoi(optval);
 924                         } else if (!strcasecmp(optname, "korate") && optval) {
 925                                 pp->korate = atoi(optval);
 926                         } else if (!strcasecmp(optname, "alwaysccaprate") && optval) {
 927                                 pp->alwaysccaprate = atoi(optval);
 928                         } else if (!strcasecmp(optname, "rate") && optval) {
 929                                 rate = atoi(optval);
 930                         } else if (!strcasecmp(optname, "fillboardtries")) {
 931                                 pp->fillboardtries = atoi(optval);
 932                         } else if (!strcasecmp(optname, "koage") && optval) {
 933                                 pp->koage = atoi(optval);
 934                         } else if (!strcasecmp(optname, "ladders")) {
 935                                 pp->ladders = optval && *optval == '0' ? false : true;
 936                         } else if (!strcasecmp(optname, "borderladders")) {
 937                                 pp->borderladders = optval && *optval == '0' ? false : true;
 938                         } else if (!strcasecmp(optname, "ladderassess")) {
 939                                 pp->ladderassess = optval && *optval == '0' ? false : true;
 940                         } else if (!strcasecmp(optname, "assess_local")) {
 941                                 pp->assess_local = optval && *optval == '0' ? false : true;
 942                         } else if (!strcasecmp(optname, "pattern2")) {
 943                                 pp->pattern2 = optval && *optval == '0' ? false : true;
 944                         } else {
 945                                 fprintf(stderr, "playout-moggy: Invalid policy argument %s or missing value\n", optname);
 946                                 exit(1);
 947                         }
 948                 }
 949         }
 950         if (pp->lcapturerate == -1) pp->lcapturerate = rate;
 951         if (pp->atarirate == -1) pp->atarirate = rate;
 952         if (pp->capturerate == -1) pp->capturerate = rate;
 953         if (pp->patternrate == -1) pp->patternrate = rate;
 954         if (pp->selfatarirate == -1) pp->selfatarirate = rate;
 955         if (pp->korate == -1) pp->korate = rate;
 956         if (pp->alwaysccaprate == -1) pp->alwaysccaprate = rate;
 957
 958         pattern3s_init(&pp->patterns, moggy_patterns_src, moggy_patterns_src_n);
 959
 960         return p;
 961 }