X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbook.cpp;h=a918d043b619e6915a483400398445c1eeb96d88;hp=bae224ba586482e7aa805281dd2bb76ba0b9f232;hb=932ae761c6e3fd3e9b202283379e487a5c187989;hpb=c97104e8540b72ee2c6c9c13d3773d2c0f9ec32f diff --git a/src/book.cpp b/src/book.cpp index bae224ba..a918d043 100644 --- a/src/book.cpp +++ b/src/book.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008 Marco Costalba + Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -20,37 +20,21 @@ /* The code in this file is based on the opening book code in PolyGlot - by Fabien Letouzey. PolyGlot is available under the GNU General + by Fabien Letouzey. PolyGlot is available under the GNU General Public License, and can be downloaded from http://wbec-ridderkerk.nl */ - -//// -//// Includes -//// - #include +#include #include "book.h" -#include "mersenne.h" #include "movegen.h" - -//// -//// Global variables -//// - -Book OpeningBook; - - -//// -//// Local definitions -//// +using namespace std; namespace { - /// Random numbers from PolyGlot, used to compute book hash keys. - + // Random numbers from PolyGlot, used to compute book hash keys const uint64_t Random64[781] = { 0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL, 0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL, @@ -315,278 +299,227 @@ namespace { 0xF8D626AAAF278509ULL }; + // Indices to the Random64[] array + const int PieceIdx = 0; + const int CastleIdx = 768; + const int EnPassantIdx = 772; + const int TurnIdx = 780; - /// Indices to the Random64[] array - - const int RandomPiece = 0; - const int RandomCastle = 768; - const int RandomEnPassant = 772; - const int RandomTurn = 780; - - - /// Convert pieces to the range 0..1 - - const int PieceTo12[] = { - 0, 0, 2, 4, 6, 8, 10, 0, 0, 1, 3, 5, 7, 9, 11 - }; - - - /// Prototypes - - uint64_t book_key(const Position &pos); - uint64_t book_piece_key(Piece p, Square s); - uint64_t book_castle_key(const Position &pos); - uint64_t book_ep_key(const Position &pos); - uint64_t book_color_key(const Position &pos); - - uint16_t read_integer16(std::ifstream& file); - uint64_t read_integer64(std::ifstream& file); - uint64_t read_integer(std::ifstream& file, int size); -} + // book_key() builds up a PolyGlot hash key out of a position + uint64_t book_key(const Position& pos) { + // Piece offset is calculated as (64 * PolyPieceType + square), where + // PolyPieceType is: BP = 0, WP = 1, BN = 2, WN = 3 .... BK = 10, WK = 11 + static const int PieceToPoly[] = { 0, 1, 3, 5, 7, 9, 11, 0, 0, 0, 2, 4, 6, 8, 10 }; -//// -//// Functions -//// + uint64_t result = 0; + Bitboard b = pos.occupied_squares(); + while (b) + { + Square s = pop_1st_bit(&b); + int p = PieceToPoly[int(pos.piece_on(s))]; + result ^= Random64[PieceIdx + 64 * p + int(s)]; + } -/// Constructor + if (pos.can_castle_kingside(WHITE)) + result ^= Random64[CastleIdx + 0]; -Book::Book() : bookSize(0) {} + if (pos.can_castle_queenside(WHITE)) + result ^= Random64[CastleIdx + 1]; + if (pos.can_castle_kingside(BLACK)) + result ^= Random64[CastleIdx + 2]; -/// Book::open() opens a book file with a given file name. + if (pos.can_castle_queenside(BLACK)) + result ^= Random64[CastleIdx + 3]; -void Book::open(const std::string &fName) { + if (pos.ep_square() != SQ_NONE) + result ^= Random64[EnPassantIdx + square_file(pos.ep_square())]; - fileName = fName; - bookFile.open(fileName.c_str(), std::ifstream::in | std::ifstream::binary); - if (!bookFile.is_open()) - return; + if (pos.side_to_move() == WHITE) + result ^= Random64[TurnIdx]; - bookFile.seekg(0, std::ios::end); - bookSize = bookFile.tellg() / 16; - bookFile.seekg(0, std::ios::beg); - - if (!bookFile.good()) - { - std::cerr << "Failed to open book file " << fileName << std::endl; - exit(EXIT_FAILURE); + return result; } -} - -/// Book::close() closes the currently open book file. - -void Book::close() { - - if (bookFile.is_open()) - bookFile.close(); } -/// Book::is_open() tests whether a book file has been opened. - -bool Book::is_open() const { +/// Book c'tor. Make random number generation less deterministic, for book moves +Book::Book() { - return bookFile.is_open() && bookSize != 0; + for (int i = abs(get_system_time() % 10000); i > 0; i--) + RKiss.rand(); } -/// Book::file_name() returns the file name of the currently active book, -/// or the empty string if no book is open. +/// Book destructor. Be sure file is closed before we leave. -const std::string Book::file_name() const { +Book::~Book() { - return bookFile.is_open() ? fileName : ""; + close(); } -/// Book::get_move() gets a book move for a given position. Returns -/// MOVE_NONE if no book move is found. +/// Book::close() closes the file only if it is open, otherwise +/// we can end up in a little mess due to how std::ifstream works. -Move Book::get_move(const Position &pos) const { - if(this->is_open()) { - int bestMove = 0, bestScore = 0, move, score; - uint64_t key = book_key(pos); - BookEntry entry; +void Book::close() { - for(int i = this->find_key(key); i < bookSize; i++) { - this->read_entry(entry, i); - if(entry.key != key) - break; - move = entry.move; - score = entry.count; - assert(score > 0); + if (is_open()) + ifstream::close(); - bestScore += score; - if(int(genrand_int32() % bestScore) < score) - bestMove = move; - } - - if(bestMove != 0) { - MoveStack moves[256]; - int n, j; - n = generate_legal_moves(pos, moves); - for(j = 0; j < n; j++) - if((int(moves[j].move) & 07777) == bestMove) - return moves[j].move; - } - } - return MOVE_NONE; + bookName = ""; } -/// Book::find_key() takes a book key as input, and does a binary search -/// through the book file for the given key. The index to the first book -/// entry with the same key as the input is returned. When the key is not -/// found in the book file, bookSize is returned. +/// Book::open() opens a book file with a given file name -int Book::find_key(uint64_t key) const { - int left, right, mid; - BookEntry entry; +void Book::open(const string& fileName) { - // Binary search (finds the leftmost entry) - left = 0; - right = bookSize - 1; + // Close old file before opening the new + close(); - assert(left <= right); + ifstream::open(fileName.c_str(), ifstream::in | ifstream::binary); - while(left < right) { - mid = (left + right) / 2; - assert(mid >= left && mid < right); + // Silently return when asked to open a non-exsistent file + if (!is_open()) + return; - this->read_entry(entry, mid); + // Get the book size in number of entries + seekg(0, ios::end); + bookSize = long(tellg()) / sizeof(BookEntry); - if(key <= entry.key) - right = mid; - else - left = mid + 1; + if (!good()) + { + cerr << "Failed to open book file " << fileName << endl; + exit(EXIT_FAILURE); } - assert(left == right); - - this->read_entry(entry, left); - - return (entry.key == key)? left : bookSize; + // Set only if successful + bookName = fileName; } -/// Book::read_entry() takes a BookEntry reference and an integer index as -/// input, and looks up the opening book entry at the given index in the book -/// file. The book entry is copied to the first input parameter. - -void Book::read_entry(BookEntry& entry, int n) const { - - assert(n >= 0 && n < bookSize); - assert(bookFile.is_open()); +/// Book::get_move() gets a book move for a given position. Returns +/// MOVE_NONE if no book move is found. If findBestMove is true then +/// return always the highest rated book move. - bookFile.seekg(n*16, std::ios_base::beg); - if (!bookFile.good()) - { - std::cerr << "Failed to read book entry at index " << n << std::endl; - exit(EXIT_FAILURE); - } - entry.key = read_integer64(bookFile); - entry.move = read_integer16(bookFile); - entry.count = read_integer16(bookFile); - entry.n = read_integer16(bookFile); - entry.sum = read_integer16(bookFile); -} +Move Book::get_move(const Position& pos, bool findBestMove) { + if (!is_open() || bookSize == 0) + return MOVE_NONE; -//// -//// Local definitions -//// + BookEntry entry; + int bookMove = MOVE_NONE; + unsigned score, scoresSum = 0, bestScore = 0; + uint64_t key = book_key(pos); -namespace { + // Choose a book move among the possible moves for the given position + for (int idx = find_entry(key); idx < bookSize; idx++) + { + entry = read_entry(idx); - uint64_t book_key(const Position &pos) { - uint64_t result = 0ULL; + if (entry.key != key) + break; - for(Color c = WHITE; c <= BLACK; c++) { - Bitboard b = pos.pieces_of_color(c); - Square s; - Piece p; - while(b != EmptyBoardBB) { - s = pop_1st_bit(&b); - p = pos.piece_on(s); - assert(piece_is_ok(p)); - assert(color_of_piece(p) == c); + score = entry.count; - result ^= book_piece_key(p, s); + if (!findBestMove) + { + // Choose book move according to its score. If a move has a very + // high score it has more probability to be choosen then a one with + // lower score. Note that first entry is always chosen. + scoresSum += score; + if (RKiss.rand() % scoresSum < score) + bookMove = entry.move; } - } + else if (score > bestScore) + { + bestScore = score; + bookMove = entry.move; + } + } - result ^= book_castle_key(pos); - result ^= book_ep_key(pos); - result ^= book_color_key(pos); + // A PolyGlot book move is encoded as follows: + // + // bit 0- 5: destination square (from 0 to 63) + // bit 6-11: origin square (from 0 to 63) + // bit 12-13-14: promotion piece (from KNIGHT == 1 to QUEEN == 4) + // + // Castling moves follow "king captures rook" representation. So in case + // book move is a promotion we have to convert to our representation, in + // all other cases we can directly compare with a Move after having + // masked out special Move's flags that are not supported by PolyGlot. + int p = (bookMove >> 12) & 7; + + if (p) + bookMove = int(make_promotion_move(move_from(Move(bookMove)), + move_to(Move(bookMove)), PieceType(p + 1))); + + // Verify the book move (if any) is legal + MoveStack mlist[MOVES_MAX]; + MoveStack* last = generate(pos, mlist); + for (MoveStack* cur = mlist; cur != last; cur++) + if ((int(cur->move) & ~(3 << 14)) == bookMove) // Mask out special flags + return cur->move; - return result; - } + return MOVE_NONE; +} - uint64_t book_piece_key(Piece p, Square s) { - return Random64[RandomPiece + (PieceTo12[int(p)]^1)*64 + int(s)]; - } +/// Book::find_entry() takes a book key as input, and does a binary search +/// through the book file for the given key. The index to the first book +/// entry with the same key as the input is returned. When the key is not +/// found in the book file, bookSize is returned. +int Book::find_entry(uint64_t key) { - uint64_t book_castle_key(const Position &pos) { - uint64_t result = 0ULL; + int left, right, mid; - if(pos.can_castle_kingside(WHITE)) - result ^= Random64[RandomCastle+0]; - if(pos.can_castle_queenside(WHITE)) - result ^= Random64[RandomCastle+1]; - if(pos.can_castle_kingside(BLACK)) - result ^= Random64[RandomCastle+2]; - if(pos.can_castle_queenside(BLACK)) - result ^= Random64[RandomCastle+3]; - return result; - } + // Binary search (finds the leftmost entry) + left = 0; + right = bookSize - 1; + assert(left <= right); - uint64_t book_ep_key(const Position &pos) { - return (pos.ep_square() == SQ_NONE)? - 0ULL : Random64[RandomEnPassant + square_file(pos.ep_square())]; - } + while (left < right) + { + mid = (left + right) / 2; + assert(mid >= left && mid < right); - uint64_t book_color_key(const Position &pos) { - return (pos.side_to_move() == WHITE)? Random64[RandomTurn] : 0ULL; + if (key <= read_entry(mid).key) + right = mid; + else + left = mid + 1; } + assert(left == right); - uint16_t read_integer16(std::ifstream& file) { - - uint64_t n = read_integer(file, 2); - assert(n == (uint16_t)n); - return (uint16_t)n; - } + return read_entry(left).key == key ? left : bookSize; +} - uint64_t read_integer64(std::ifstream& file) { +/// Book::read_entry() takes an integer index, and returns the BookEntry +/// at the given index in the book file. - return read_integer(file, 8); - } +BookEntry Book::read_entry(int idx) { + assert(idx >= 0 && idx < bookSize); + assert(is_open()); - uint64_t read_integer(std::ifstream& file, int size) { + BookEntry e; - char buf[8]; - file.read(buf, size); + seekg(idx * sizeof(BookEntry), ios_base::beg); - if (!file.good()) - { - std::cerr << "Failed to read " << size << " bytes from book file" - << std::endl; - exit(EXIT_FAILURE); - } - // Numbers are stored in little endian format - uint64_t n = 0ULL; - for (int i = 0; i < size; i++) - n = (n << 8) + (unsigned char)buf[i]; + *this >> e.key >> e.move >> e.count >> e.learn; - return n; + if (!good()) + { + cerr << "Failed to read book entry at index " << idx << endl; + exit(EXIT_FAILURE); } + return e; }