git.sesse.net Git - stockfish/blob - src/book.cpp

   1 /*
   2   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   3   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   4   Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
   5
   6   Stockfish is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   Stockfish is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /*
  21   The code in this file is based on the opening book code in PolyGlot
  22   by Fabien Letouzey. PolyGlot is available under the GNU General
  23   Public License, and can be downloaded from http://wbec-ridderkerk.nl
  24 */
  25
  26 #include <algorithm>
  27 #include <cassert>
  28 #include <iostream>
  29
  30 #include "book.h"
  31 #include "misc.h"
  32 #include "movegen.h"
  33
  34 using namespace std;
  35
  36 namespace {
  37
  38   // A Polyglot book is a series of "entries" of 16 bytes. All integers are
  39   // stored in big-endian format, with highest byte first (regardless of size).
  40   // The entries are ordered according to the key in ascending order.
  41   struct Entry {
  42     uint64_t key;
  43     uint16_t move;
  44     uint16_t count;
  45     uint32_t learn;
  46   };
  47
  48   // Random numbers from PolyGlot, used to compute book hash keys
  49   const union {
  50     Key PolyGlotRandoms[781];
  51     struct {
  52       Key psq[12][64];  // [piece][square]
  53       Key castle[4];    // [castle right]
  54       Key enpassant[8]; // [file]
  55       Key turn;
  56     } Zobrist;
  57   } PG = {{
  58     0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL,
  59     0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL,
  60     0x0FBBAD1F61042279ULL, 0xE83A908FF2FB60CAULL, 0x0D7E765D58755C10ULL,
  61     0x1A083822CEAFE02DULL, 0x9605D5F0E25EC3B0ULL, 0xD021FF5CD13A2ED5ULL,
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 202     0x604D51B25FBF70E2ULL, 0x73AA8A564FB7AC9EULL, 0x1A8C1E992B941148ULL,
 203     0xAAC40A2703D9BEA0ULL, 0x764DBEAE7FA4F3A6ULL, 0x1E99B96E70A9BE8BULL,
 204     0x2C5E9DEB57EF4743ULL, 0x3A938FEE32D29981ULL, 0x26E6DB8FFDF5ADFEULL,
 205     0x469356C504EC9F9DULL, 0xC8763C5B08D1908CULL, 0x3F6C6AF859D80055ULL,
 206     0x7F7CC39420A3A545ULL, 0x9BFB227EBDF4C5CEULL, 0x89039D79D6FC5C5CULL,
 207     0x8FE88B57305E2AB6ULL, 0xA09E8C8C35AB96DEULL, 0xFA7E393983325753ULL,
 208     0xD6B6D0ECC617C699ULL, 0xDFEA21EA9E7557E3ULL, 0xB67C1FA481680AF8ULL,
 209     0xCA1E3785A9E724E5ULL, 0x1CFC8BED0D681639ULL, 0xD18D8549D140CAEAULL,
 210     0x4ED0FE7E9DC91335ULL, 0xE4DBF0634473F5D2ULL, 0x1761F93A44D5AEFEULL,
 211     0x53898E4C3910DA55ULL, 0x734DE8181F6EC39AULL, 0x2680B122BAA28D97ULL,
 212     0x298AF231C85BAFABULL, 0x7983EED3740847D5ULL, 0x66C1A2A1A60CD889ULL,
 213     0x9E17E49642A3E4C1ULL, 0xEDB454E7BADC0805ULL, 0x50B704CAB602C329ULL,
 214     0x4CC317FB9CDDD023ULL, 0x66B4835D9EAFEA22ULL, 0x219B97E26FFC81BDULL,
 215     0x261E4E4C0A333A9DULL, 0x1FE2CCA76517DB90ULL, 0xD7504DFA8816EDBBULL,
 216     0xB9571FA04DC089C8ULL, 0x1DDC0325259B27DEULL, 0xCF3F4688801EB9AAULL,
 217     0xF4F5D05C10CAB243ULL, 0x38B6525C21A42B0EULL, 0x36F60E2BA4FA6800ULL,
 218     0xEB3593803173E0CEULL, 0x9C4CD6257C5A3603ULL, 0xAF0C317D32ADAA8AULL,
 219     0x258E5A80C7204C4BULL, 0x8B889D624D44885DULL, 0xF4D14597E660F855ULL,
 220     0xD4347F66EC8941C3ULL, 0xE699ED85B0DFB40DULL, 0x2472F6207C2D0484ULL,
 221     0xC2A1E7B5B459AEB5ULL, 0xAB4F6451CC1D45ECULL, 0x63767572AE3D6174ULL,
 222     0xA59E0BD101731A28ULL, 0x116D0016CB948F09ULL, 0x2CF9C8CA052F6E9FULL,
 223     0x0B090A7560A968E3ULL, 0xABEEDDB2DDE06FF1ULL, 0x58EFC10B06A2068DULL,
 224     0xC6E57A78FBD986E0ULL, 0x2EAB8CA63CE802D7ULL, 0x14A195640116F336ULL,
 225     0x7C0828DD624EC390ULL, 0xD74BBE77E6116AC7ULL, 0x804456AF10F5FB53ULL,
 226     0xEBE9EA2ADF4321C7ULL, 0x03219A39EE587A30ULL, 0x49787FEF17AF9924ULL,
 227     0xA1E9300CD8520548ULL, 0x5B45E522E4B1B4EFULL, 0xB49C3B3995091A36ULL,
 228     0xD4490AD526F14431ULL, 0x12A8F216AF9418C2ULL, 0x001F837CC7350524ULL,
 229     0x1877B51E57A764D5ULL, 0xA2853B80F17F58EEULL, 0x993E1DE72D36D310ULL,
 230     0xB3598080CE64A656ULL, 0x252F59CF0D9F04BBULL, 0xD23C8E176D113600ULL,
 231     0x1BDA0492E7E4586EULL, 0x21E0BD5026C619BFULL, 0x3B097ADAF088F94EULL,
 232     0x8D14DEDB30BE846EULL, 0xF95CFFA23AF5F6F4ULL, 0x3871700761B3F743ULL,
 233     0xCA672B91E9E4FA16ULL, 0x64C8E531BFF53B55ULL, 0x241260ED4AD1E87DULL,
 234     0x106C09B972D2E822ULL, 0x7FBA195410E5CA30ULL, 0x7884D9BC6CB569D8ULL,
 235     0x0647DFEDCD894A29ULL, 0x63573FF03E224774ULL, 0x4FC8E9560F91B123ULL,
 236     0x1DB956E450275779ULL, 0xB8D91274B9E9D4FBULL, 0xA2EBEE47E2FBFCE1ULL,
 237     0xD9F1F30CCD97FB09ULL, 0xEFED53D75FD64E6BULL, 0x2E6D02C36017F67FULL,
 238     0xA9AA4D20DB084E9BULL, 0xB64BE8D8B25396C1ULL, 0x70CB6AF7C2D5BCF0ULL,
 239     0x98F076A4F7A2322EULL, 0xBF84470805E69B5FULL, 0x94C3251F06F90CF3ULL,
 240     0x3E003E616A6591E9ULL, 0xB925A6CD0421AFF3ULL, 0x61BDD1307C66E300ULL,
 241     0xBF8D5108E27E0D48ULL, 0x240AB57A8B888B20ULL, 0xFC87614BAF287E07ULL,
 242     0xEF02CDD06FFDB432ULL, 0xA1082C0466DF6C0AULL, 0x8215E577001332C8ULL,
 243     0xD39BB9C3A48DB6CFULL, 0x2738259634305C14ULL, 0x61CF4F94C97DF93DULL,
 244     0x1B6BACA2AE4E125BULL, 0x758F450C88572E0BULL, 0x959F587D507A8359ULL,
 245     0xB063E962E045F54DULL, 0x60E8ED72C0DFF5D1ULL, 0x7B64978555326F9FULL,
 246     0xFD080D236DA814BAULL, 0x8C90FD9B083F4558ULL, 0x106F72FE81E2C590ULL,
 247     0x7976033A39F7D952ULL, 0xA4EC0132764CA04BULL, 0x733EA705FAE4FA77ULL,
 248     0xB4D8F77BC3E56167ULL, 0x9E21F4F903B33FD9ULL, 0x9D765E419FB69F6DULL,
 249     0xD30C088BA61EA5EFULL, 0x5D94337FBFAF7F5BULL, 0x1A4E4822EB4D7A59ULL,
 250     0x6FFE73E81B637FB3ULL, 0xDDF957BC36D8B9CAULL, 0x64D0E29EEA8838B3ULL,
 251     0x08DD9BDFD96B9F63ULL, 0x087E79E5A57D1D13ULL, 0xE328E230E3E2B3FBULL,
 252     0x1C2559E30F0946BEULL, 0x720BF5F26F4D2EAAULL, 0xB0774D261CC609DBULL,
 253     0x443F64EC5A371195ULL, 0x4112CF68649A260EULL, 0xD813F2FAB7F5C5CAULL,
 254     0x660D3257380841EEULL, 0x59AC2C7873F910A3ULL, 0xE846963877671A17ULL,
 255     0x93B633ABFA3469F8ULL, 0xC0C0F5A60EF4CDCFULL, 0xCAF21ECD4377B28CULL,
 256     0x57277707199B8175ULL, 0x506C11B9D90E8B1DULL, 0xD83CC2687A19255FULL,
 257     0x4A29C6465A314CD1ULL, 0xED2DF21216235097ULL, 0xB5635C95FF7296E2ULL,
 258     0x22AF003AB672E811ULL, 0x52E762596BF68235ULL, 0x9AEBA33AC6ECC6B0ULL,
 259     0x944F6DE09134DFB6ULL, 0x6C47BEC883A7DE39ULL, 0x6AD047C430A12104ULL,
 260     0xA5B1CFDBA0AB4067ULL, 0x7C45D833AFF07862ULL, 0x5092EF950A16DA0BULL,
 261     0x9338E69C052B8E7BULL, 0x455A4B4CFE30E3F5ULL, 0x6B02E63195AD0CF8ULL,
 262     0x6B17B224BAD6BF27ULL, 0xD1E0CCD25BB9C169ULL, 0xDE0C89A556B9AE70ULL,
 263     0x50065E535A213CF6ULL, 0x9C1169FA2777B874ULL, 0x78EDEFD694AF1EEDULL,
 264     0x6DC93D9526A50E68ULL, 0xEE97F453F06791EDULL, 0x32AB0EDB696703D3ULL,
 265     0x3A6853C7E70757A7ULL, 0x31865CED6120F37DULL, 0x67FEF95D92607890ULL,
 266     0x1F2B1D1F15F6DC9CULL, 0xB69E38A8965C6B65ULL, 0xAA9119FF184CCCF4ULL,
 267     0xF43C732873F24C13ULL, 0xFB4A3D794A9A80D2ULL, 0x3550C2321FD6109CULL,
 268     0x371F77E76BB8417EULL, 0x6BFA9AAE5EC05779ULL, 0xCD04F3FF001A4778ULL,
 269     0xE3273522064480CAULL, 0x9F91508BFFCFC14AULL, 0x049A7F41061A9E60ULL,
 270     0xFCB6BE43A9F2FE9BULL, 0x08DE8A1C7797DA9BULL, 0x8F9887E6078735A1ULL,
 271     0xB5B4071DBFC73A66ULL, 0x230E343DFBA08D33ULL, 0x43ED7F5A0FAE657DULL,
 272     0x3A88A0FBBCB05C63ULL, 0x21874B8B4D2DBC4FULL, 0x1BDEA12E35F6A8C9ULL,
 273     0x53C065C6C8E63528ULL, 0xE34A1D250E7A8D6BULL, 0xD6B04D3B7651DD7EULL,
 274     0x5E90277E7CB39E2DULL, 0x2C046F22062DC67DULL, 0xB10BB459132D0A26ULL,
 275     0x3FA9DDFB67E2F199ULL, 0x0E09B88E1914F7AFULL, 0x10E8B35AF3EEAB37ULL,
 276     0x9EEDECA8E272B933ULL, 0xD4C718BC4AE8AE5FULL, 0x81536D601170FC20ULL,
 277     0x91B534F885818A06ULL, 0xEC8177F83F900978ULL, 0x190E714FADA5156EULL,
 278     0xB592BF39B0364963ULL, 0x89C350C893AE7DC1ULL, 0xAC042E70F8B383F2ULL,
 279     0xB49B52E587A1EE60ULL, 0xFB152FE3FF26DA89ULL, 0x3E666E6F69AE2C15ULL,
 280     0x3B544EBE544C19F9ULL, 0xE805A1E290CF2456ULL, 0x24B33C9D7ED25117ULL,
 281     0xE74733427B72F0C1ULL, 0x0A804D18B7097475ULL, 0x57E3306D881EDB4FULL,
 282     0x4AE7D6A36EB5DBCBULL, 0x2D8D5432157064C8ULL, 0xD1E649DE1E7F268BULL,
 283     0x8A328A1CEDFE552CULL, 0x07A3AEC79624C7DAULL, 0x84547DDC3E203C94ULL,
 284     0x990A98FD5071D263ULL, 0x1A4FF12616EEFC89ULL, 0xF6F7FD1431714200ULL,
 285     0x30C05B1BA332F41CULL, 0x8D2636B81555A786ULL, 0x46C9FEB55D120902ULL,
 286     0xCCEC0A73B49C9921ULL, 0x4E9D2827355FC492ULL, 0x19EBB029435DCB0FULL,
 287     0x4659D2B743848A2CULL, 0x963EF2C96B33BE31ULL, 0x74F85198B05A2E7DULL,
 288     0x5A0F544DD2B1FB18ULL, 0x03727073C2E134B1ULL, 0xC7F6AA2DE59AEA61ULL,
 289     0x352787BAA0D7C22FULL, 0x9853EAB63B5E0B35ULL, 0xABBDCDD7ED5C0860ULL,
 290     0xCF05DAF5AC8D77B0ULL, 0x49CAD48CEBF4A71EULL, 0x7A4C10EC2158C4A6ULL,
 291     0xD9E92AA246BF719EULL, 0x13AE978D09FE5557ULL, 0x730499AF921549FFULL,
 292     0x4E4B705B92903BA4ULL, 0xFF577222C14F0A3AULL, 0x55B6344CF97AAFAEULL,
 293     0xB862225B055B6960ULL, 0xCAC09AFBDDD2CDB4ULL, 0xDAF8E9829FE96B5FULL,
 294     0xB5FDFC5D3132C498ULL, 0x310CB380DB6F7503ULL, 0xE87FBB46217A360EULL,
 295     0x2102AE466EBB1148ULL, 0xF8549E1A3AA5E00DULL, 0x07A69AFDCC42261AULL,
 296     0xC4C118BFE78FEAAEULL, 0xF9F4892ED96BD438ULL, 0x1AF3DBE25D8F45DAULL,
 297     0xF5B4B0B0D2DEEEB4ULL, 0x962ACEEFA82E1C84ULL, 0x046E3ECAAF453CE9ULL,
 298     0xF05D129681949A4CULL, 0x964781CE734B3C84ULL, 0x9C2ED44081CE5FBDULL,
 299     0x522E23F3925E319EULL, 0x177E00F9FC32F791ULL, 0x2BC60A63A6F3B3F2ULL,
 300     0x222BBFAE61725606ULL, 0x486289DDCC3D6780ULL, 0x7DC7785B8EFDFC80ULL,
 301     0x8AF38731C02BA980ULL, 0x1FAB64EA29A2DDF7ULL, 0xE4D9429322CD065AULL,
 302     0x9DA058C67844F20CULL, 0x24C0E332B70019B0ULL, 0x233003B5A6CFE6ADULL,
 303     0xD586BD01C5C217F6ULL, 0x5E5637885F29BC2BULL, 0x7EBA726D8C94094BULL,
 304     0x0A56A5F0BFE39272ULL, 0xD79476A84EE20D06ULL, 0x9E4C1269BAA4BF37ULL,
 305     0x17EFEE45B0DEE640ULL, 0x1D95B0A5FCF90BC6ULL, 0x93CBE0B699C2585DULL,
 306     0x65FA4F227A2B6D79ULL, 0xD5F9E858292504D5ULL, 0xC2B5A03F71471A6FULL,
 307     0x59300222B4561E00ULL, 0xCE2F8642CA0712DCULL, 0x7CA9723FBB2E8988ULL,
 308     0x2785338347F2BA08ULL, 0xC61BB3A141E50E8CULL, 0x150F361DAB9DEC26ULL,
 309     0x9F6A419D382595F4ULL, 0x64A53DC924FE7AC9ULL, 0x142DE49FFF7A7C3DULL,
 310     0x0C335248857FA9E7ULL, 0x0A9C32D5EAE45305ULL, 0xE6C42178C4BBB92EULL,
 311     0x71F1CE2490D20B07ULL, 0xF1BCC3D275AFE51AULL, 0xE728E8C83C334074ULL,
 312     0x96FBF83A12884624ULL, 0x81A1549FD6573DA5ULL, 0x5FA7867CAF35E149ULL,
 313     0x56986E2EF3ED091BULL, 0x917F1DD5F8886C61ULL, 0xD20D8C88C8FFE65FULL,
 314     0x31D71DCE64B2C310ULL, 0xF165B587DF898190ULL, 0xA57E6339DD2CF3A0ULL,
 315     0x1EF6E6DBB1961EC9ULL, 0x70CC73D90BC26E24ULL, 0xE21A6B35DF0C3AD7ULL,
 316     0x003A93D8B2806962ULL, 0x1C99DED33CB890A1ULL, 0xCF3145DE0ADD4289ULL,
 317     0xD0E4427A5514FB72ULL, 0x77C621CC9FB3A483ULL, 0x67A34DAC4356550BULL,
 318     0xF8D626AAAF278509ULL
 319   }};
 320
 321   // polyglot_key() returns the PolyGlot hash key of the given position
 322   Key polyglot_key(const Position& pos) {
 323
 324     Key key = 0;
 325     Bitboard b = pos.pieces();
 326
 327     while (b)
 328     {
 329         Square s = pop_lsb(&b);
 330         Piece p = pos.piece_on(s);
 331
 332         // PolyGlot pieces are: BP = 0, WP = 1, BN = 2, ... BK = 10, WK = 11
 333         key ^= PG.Zobrist.psq[2 * (type_of(p) - 1) + (color_of(p) == WHITE)][s];
 334     }
 335
 336     b = pos.can_castle(ALL_CASTLES);
 337
 338     while (b)
 339         key ^= PG.Zobrist.castle[pop_lsb(&b)];
 340
 341     if (pos.ep_square() != SQ_NONE)
 342         key ^= PG.Zobrist.enpassant[file_of(pos.ep_square())];
 343
 344     if (pos.side_to_move() == WHITE)
 345         key ^= PG.Zobrist.turn;
 346
 347     return key;
 348   }
 349
 350 } // namespace
 351
 352 PolyglotBook::PolyglotBook() : rkiss(Time::now() % 10000) {}
 353
 354 PolyglotBook::~PolyglotBook() { if (is_open()) close(); }
 355
 356
 357 /// operator>>() reads sizeof(T) chars from the file's binary byte stream and
 358 /// converts them in a number of type T. A Polyglot book stores numbers in
 359 /// big-endian format.
 360
 361 template<typename T> PolyglotBook& PolyglotBook::operator>>(T& n) {
 362
 363   n = 0;
 364   for (size_t i = 0; i < sizeof(T); ++i)
 365       n = T((n << 8) + ifstream::get());
 366
 367   return *this;
 368 }
 369
 370 template<> PolyglotBook& PolyglotBook::operator>>(Entry& e) {
 371   return *this >> e.key >> e.move >> e.count >> e.learn;
 372 }
 373
 374
 375 /// open() tries to open a book file with the given name after closing any
 376 /// exsisting one.
 377
 378 bool PolyglotBook::open(const char* fName) {
 379
 380   if (is_open()) // Cannot close an already closed file
 381       close();
 382
 383   ifstream::open(fName, ifstream::in | ifstream::binary);
 384
 385   fileName = is_open() ? fName : "";
 386   ifstream::clear(); // Reset any error flag to allow retry ifstream::open()
 387   return !fileName.empty();
 388 }
 389
 390
 391 /// probe() tries to find a book move for the given position. If no move is
 392 /// found returns MOVE_NONE. If pickBest is true returns always the highest
 393 /// rated move, otherwise randomly chooses one, based on the move score.
 394
 395 Move PolyglotBook::probe(const Position& pos, const string& fName, bool pickBest) {
 396
 397   if (fileName != fName && !open(fName.c_str()))
 398       return MOVE_NONE;
 399
 400   Entry e;
 401   uint16_t best = 0;
 402   unsigned sum = 0;
 403   Move move = MOVE_NONE;
 404   Key key = polyglot_key(pos);
 405
 406   seekg(find_first(key) * sizeof(Entry), ios_base::beg);
 407
 408   while (*this >> e, e.key == key && good())
 409   {
 410       best = max(best, e.count);
 411       sum += e.count;
 412
 413       // Choose book move according to its score. If a move has a very
 414       // high score it has higher probability to be choosen than a move
 415       // with lower score. Note that first entry is always chosen.
 416       if (   (!pickBest && sum && rkiss.rand<unsigned>() % sum < e.count)
 417           || (pickBest && e.count == best))
 418           move = Move(e.move);
 419   }
 420
 421   if (!move)
 422       return MOVE_NONE;
 423
 424   // A PolyGlot book move is encoded as follows:
 425   //
 426   // bit  0- 5: destination square (from 0 to 63)
 427   // bit  6-11: origin square (from 0 to 63)
 428   // bit 12-14: promotion piece (from KNIGHT == 1 to QUEEN == 4)
 429   //
 430   // Castling moves follow "king captures rook" representation. So in case book
 431   // move is a promotion we have to convert to our representation, in all the
 432   // other cases we can directly compare with a Move after having masked out
 433   // the special Move's flags (bit 14-15) that are not supported by PolyGlot.
 434   int pt = (move >> 12) & 7;
 435   if (pt)
 436       move = make<PROMOTION>(from_sq(move), to_sq(move), PieceType(pt + 1));
 437
 438   // Add 'special move' flags and verify it is legal
 439   for (MoveList<LEGAL> it(pos); *it; ++it)
 440       if (move == (*it ^ type_of(*it)))
 441           return *it;
 442
 443   return MOVE_NONE;
 444 }
 445
 446
 447 /// find_first() takes a book key as input, and does a binary search through
 448 /// the book file for the given key. Returns the index of the leftmost book
 449 /// entry with the same key as the input.
 450
 451 size_t PolyglotBook::find_first(Key key) {
 452
 453   seekg(0, ios::end); // Move pointer to end, so tellg() gets file's size
 454
 455   size_t low = 0, mid, high = (size_t)tellg() / sizeof(Entry) - 1;
 456   Entry e;
 457
 458   assert(low <= high);
 459
 460   while (low < high && good())
 461   {
 462       mid = (low + high) / 2;
 463
 464       assert(mid >= low && mid < high);
 465
 466       seekg(mid * sizeof(Entry), ios_base::beg);
 467       *this >> e;
 468
 469       if (key <= e.key)
 470           high = mid;
 471       else
 472           low = mid + 1;
 473   }
 474
 475   assert(low == high);
 476
 477   return low;
 478 }