X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbook.cpp;h=8c7cd52c5ca39c482101d87f245bafcca9ef944e;hp=a34d17b74ca7dc13c46c4ab0535b9d0d639356c3;hb=c9d7e99de682516c560009b550c41da9ae2008b8;hpb=f5e28ef5127ff29310f9c2e8e321eb24214f2439 diff --git a/src/book.cpp b/src/book.cpp index a34d17b7..8c7cd52c 100644 --- a/src/book.cpp +++ b/src/book.cpp @@ -20,41 +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 "movegen.h" using namespace std; -//// -//// Global variables -//// - -Book OpeningBook; - - -//// -//// Local definitions -//// - namespace { - /// Book entry size in bytes - const int EntrySize = 16; - - - /// 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, @@ -319,38 +299,62 @@ 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 + // book_key() builds up a PolyGlot hash key out of a position + uint64_t book_key(const Position& pos) { - const int RandomPiece = 0; - const int RandomCastle = 768; - const int RandomEnPassant = 772; - const int RandomTurn = 780; + // 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 }; + uint64_t result = 0; + Bitboard b = pos.occupied_squares(); - /// Prototypes + while (b) + { + Square s = pop_1st_bit(&b); + int p = PieceToPoly[int(pos.piece_on(s))]; + result ^= Random64[PieceIdx + 64 * p + int(s)]; + } - 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); -} + if (pos.can_castle_kingside(WHITE)) + result ^= Random64[CastleIdx + 0]; + + if (pos.can_castle_queenside(WHITE)) + result ^= Random64[CastleIdx + 1]; + + if (pos.can_castle_kingside(BLACK)) + result ^= Random64[CastleIdx + 2]; + + if (pos.can_castle_queenside(BLACK)) + result ^= Random64[CastleIdx + 3]; + if (pos.ep_square() != SQ_NONE) + result ^= Random64[EnPassantIdx + square_file(pos.ep_square())]; + + if (pos.side_to_move() == WHITE) + result ^= Random64[TurnIdx]; + + return result; + } + +} -//// -//// Functions -//// -// C'tor. Make random number generation less deterministic, for book moves +/// Book c'tor. Make random number generation less deterministic, for book moves Book::Book() { for (int i = abs(get_system_time() % 10000); i > 0; i--) - RKiss.rand32(); + RKiss.rand(); } -/// Destructor. Be sure file is closed before we leave. +/// Book destructor. Be sure file is closed before we leave. Book::~Book() { @@ -358,114 +362,121 @@ Book::~Book() { } +/// 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. + +void Book::close() { + + if (bookFile.is_open()) + bookFile.close(); + + bookName = ""; +} + + /// Book::open() opens a book file with a given file name -void Book::open(const string& fName) { +void Book::open(const string& fileName) { // Close old file before opening the new close(); - fileName = fName; - ifstream::open(fileName.c_str(), ifstream::in | ifstream::binary); - if (!is_open()) + bookFile.open(fileName.c_str(), ifstream::in | ifstream::binary); + + // Silently return when asked to open a non-exsistent file + if (!bookFile.is_open()) return; // Get the book size in number of entries - seekg(0, ios::end); - bookSize = long(tellg()) / EntrySize; - seekg(0, ios::beg); + bookFile.seekg(0, ios::end); + bookSize = long(bookFile.tellg()) / sizeof(BookEntry); - if (!good()) + if (!bookFile.good()) { cerr << "Failed to open book file " << fileName << endl; - Application::exit_with_failure(); + exit(EXIT_FAILURE); } -} - -/// 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. - -void Book::close() { - - if (is_open()) - ifstream::close(); -} - - -/// Book::file_name() returns the file name of the currently active book, -/// or the empty string if no book is open. - -const string Book::file_name() { // Not const to compile on HP-UX 11.X - - return is_open() ? fileName : ""; + // Set only if successful + bookName = fileName; } /// Book::get_move() gets a book move for a given position. Returns -/// MOVE_NONE if no book move is found. +/// MOVE_NONE if no book move is found. If findBestMove is true then +/// return always the highest rated book move. Move Book::get_move(const Position& pos, bool findBestMove) { - if (!is_open() || bookSize == 0) + if (!bookFile.is_open() || bookSize == 0) return MOVE_NONE; BookEntry entry; int bookMove = MOVE_NONE; - int scoresSum = 0, bestScore = 0; + unsigned score, scoresSum = 0, bestScore = 0; uint64_t key = book_key(pos); // Choose a book move among the possible moves for the given position - for (int idx = find_key(key); idx < bookSize; idx++) + for (int idx = find_entry(key); idx < bookSize; idx++) { - read_entry(entry, idx); + entry = read_entry(idx); + if (entry.key != key) break; - int score = entry.count; - - assert(score > 0); + score = entry.count; - // If findBestMove is true choose highest rated book move - if (findBestMove) + if (!findBestMove) { - if (score > bestScore) - { - bestScore = score; + // 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; - } - continue; } - - // 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 (int(RKiss.rand32() % scoresSum) < score) + else if (score > bestScore) + { + bestScore = score; bookMove = entry.move; + } } - if (!bookMove) - return MOVE_NONE; - MoveStack mlist[MOVES_MAX]; - MoveStack* last = generate_moves(pos, mlist); + // 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[MAX_MOVES]; + MoveStack* last = generate(pos, mlist); for (MoveStack* cur = mlist; cur != last; cur++) - if ((int(cur->move) & 07777) == bookMove) + if ((int(cur->move) & ~(3 << 14)) == bookMove) // Mask out special flags return cur->move; return MOVE_NONE; } -/// Book::find_key() takes a book key as input, and does a binary search +/// 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_key(uint64_t key) { +int Book::find_entry(uint64_t key) { int left, right, mid; - BookEntry entry; // Binary search (finds the leftmost entry) left = 0; @@ -479,8 +490,7 @@ int Book::find_key(uint64_t key) { assert(mid >= left && mid < right); - read_entry(entry, mid); - if (key <= entry.key) + if (key <= read_entry(mid).key) right = mid; else left = mid + 1; @@ -488,114 +498,28 @@ int Book::find_key(uint64_t key) { assert(left == right); - read_entry(entry, left); - return (entry.key == key)? left : bookSize; + return read_entry(left).key == key ? left : bookSize; } -/// 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. +/// Book::read_entry() takes an integer index, and returns the BookEntry +/// at the given index in the book file. -void Book::read_entry(BookEntry& entry, int idx) { +BookEntry Book::read_entry(int idx) { assert(idx >= 0 && idx < bookSize); - assert(is_open()); - - seekg(idx * EntrySize, ios_base::beg); - *this >> entry; - if (!good()) - { - cerr << "Failed to read book entry at index " << idx << endl; - Application::exit_with_failure(); - } -} - - -/// Book::read_integer() reads size chars from the file stream -/// and converts them in an integer number. - -uint64_t Book::read_integer(int size) { - - char buf[8]; - read(buf, size); - - // Numbers are stored on disk as a binary byte stream - uint64_t n = 0; - for (int i = 0; i < size; i++) - n = (n << 8) + (unsigned char)buf[i]; - - return n; -} + assert(bookFile.is_open()); + BookEntry e; -//// -//// Local definitions -//// + bookFile.seekg(idx * sizeof(BookEntry), ios_base::beg); -namespace { - - uint64_t book_key(const Position& pos) { - - uint64_t result = 0; - - for (Color c = WHITE; c <= BLACK; c++) - { - Bitboard b = pos.pieces_of_color(c); - - while (b) - { - Square s = pop_1st_bit(&b); - Piece p = pos.piece_on(s); - - assert(piece_is_ok(p)); - assert(color_of_piece(p) == c); - - result ^= book_piece_key(p, s); - } - } - result ^= book_castle_key(pos); - result ^= book_ep_key(pos); - result ^= book_color_key(pos); - return result; - } + *this >> e.key >> e.move >> e.count >> e.learn; - - uint64_t book_piece_key(Piece p, Square s) { - - /// Convert pieces to the range 0..11 - static const int PieceTo12[] = { 0, 0, 2, 4, 6, 8, 10, 0, 0, 1, 3, 5, 7, 9, 11 }; - - return Random64[RandomPiece + (PieceTo12[int(p)]^1) * 64 + int(s)]; - } - - - uint64_t book_castle_key(const Position& pos) { - - uint64_t result = 0; - - 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; - } - - - uint64_t book_ep_key(const Position& pos) { - return pos.ep_square() == SQ_NONE ? 0 : Random64[RandomEnPassant + square_file(pos.ep_square())]; - } - - - uint64_t book_color_key(const Position& pos) { - return pos.side_to_move() == WHITE ? Random64[RandomTurn] : 0; + if (!bookFile.good()) + { + cerr << "Failed to read book entry at index " << idx << endl; + exit(EXIT_FAILURE); } + return e; }