X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbook.cpp;h=243583ff18276000a7c5050f0a54ffe330ff0bff;hp=7cb0863c11158b2f414a0c2868d0a8041b5b3cf9;hb=80dd90f9722ecedb48605a6cd59e2d59a1bb2495;hpb=bdfd656c2400ea66cfdbd7dae9ca6bfd505e91c7 diff --git a/src/book.cpp b/src/book.cpp index 7cb0863c..243583ff 100644 --- a/src/book.cpp +++ b/src/book.cpp @@ -20,33 +20,22 @@ /* 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; -//// -//// Local definitions -//// - namespace { - // Book entry size in bytes - const int EntrySize = 16; - // Random numbers from PolyGlot, used to compute book hash keys - const uint64_t Random64[781] = { + const Key PolyGlotRandoms[781] = { 0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL, 0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL, 0x0FBBAD1F61042279ULL, 0xE83A908FF2FB60CAULL, 0x0D7E765D58755C10ULL, @@ -310,34 +299,61 @@ namespace { 0xF8D626AAAF278509ULL }; - // Indices to the Random64[] array - const int PieceIdx = 0; - const int CastleIdx = 768; - const int EnPassantIdx = 772; - const int TurnIdx = 780; - - // Local functions - 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); -} + // Offsets to the PolyGlotRandoms[] array of zobrist keys + const Key* ZobPiece = PolyGlotRandoms + 0; + const Key* ZobCastle = PolyGlotRandoms + 768; + const Key* ZobEnPassant = PolyGlotRandoms + 772; + const Key* ZobTurn = PolyGlotRandoms + 780; + + // Piece offset is calculated as 64 * (PolyPiece ^ 1) where + // PolyPiece is: BP = 0, WP = 1, BN = 2, WN = 3 ... BK = 10, WK = 11 + const int PieceOfs[] = { 0, 64, 192, 320, 448, 576, 704, 0, + 0, 0, 128, 256, 384, 512, 640 }; + + // book_key() builds up a PolyGlot hash key out of a position + uint64_t book_key(const Position& pos) { + + uint64_t result = 0; + Bitboard b = pos.occupied_squares(); + while (b) + { + Square s = pop_1st_bit(&b); + result ^= ZobPiece[PieceOfs[pos.piece_on(s)] + s]; + } + + if (pos.can_castle(WHITE_OO)) + result ^= ZobCastle[0]; + + if (pos.can_castle(WHITE_OOO)) + result ^= ZobCastle[1]; -//// -//// Functions -//// + if (pos.can_castle(BLACK_OO)) + result ^= ZobCastle[2]; -// C'tor. Make random number generation less deterministic, for book moves -Book::Book() { + if (pos.can_castle(BLACK_OOO)) + result ^= ZobCastle[3]; + + if (pos.ep_square() != SQ_NONE) + result ^= ZobEnPassant[file_of(pos.ep_square())]; + + if (pos.side_to_move() == WHITE) + result ^= ZobTurn[0]; + + return result; + } +} + + +/// Book c'tor. Make random number generation less deterministic, for book moves +Book::Book() : bookSize(0) { for (int i = abs(get_system_time() % 10000); i > 0; i--) RKiss.rand(); } -/// Destructor. Be sure file is closed before we leave. +/// Book destructor. Be sure file is closed before we leave. Book::~Book() { @@ -345,115 +361,114 @@ 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. +/// Book::close() closes the file only if it is open, otherwise the call fails +/// and the failbit internal state flag is set. void Book::close() { - if (is_open()) - ifstream::close(); + if (bookFile.is_open()) + bookFile.close(); + + bookName = ""; + bookSize = 0; } -/// Book::open() opens a book file with a given file name +/// Book::open() opens a book file with a given 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); + bookFile.open(fileName.c_str(), ifstream::in | ifstream::binary |ios::ate); - if (is_open()) - { - // Get the book size in number of entries - seekg(0, ios::end); - bookSize = long(tellg()) / EntrySize; - seekg(0, ios::beg); + // Silently return when asked to open a non-exsistent file + if (!bookFile.is_open()) + return; - if (good()) - return; - } - cerr << "Failed to open book file " << fileName << endl; - Application::exit_with_failure(); -} - - -/// Book::file_name() returns the file name of the currently active book, -/// or the empty string if no book is open. + // Get the book size in number of entries, we are already at the file end + bookSize = long(bookFile.tellg()) / sizeof(BookEntry); -const string Book::file_name() { // Not const to compile on HP-UX 11.X + if (!bookFile.good()) + { + cerr << "Failed to open book file " << fileName << endl; + exit(EXIT_FAILURE); + } - 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. +/// Book::probe() gets a book move for a given position. Returns MOVE_NONE +/// if no book move is found. If findBest is true then returns always the +/// highest rated move otherwise chooses randomly based on the move score. -Move Book::get_move(const Position& pos, bool findBestMove) { +Move Book::probe(const Position& pos, bool findBest) { - if (!is_open() || bookSize == 0) + if (!bookSize || !bookFile.is_open()) return MOVE_NONE; BookEntry entry; - int bookMove = MOVE_NONE; - unsigned scoresSum = 0, bestScore = 0; + unsigned scoresSum = 0, bestScore = 0, bookMove = 0; uint64_t key = book_key(pos); + int idx = first_entry(key) - 1; // Choose a book move among the possible moves for the given position - for (int idx = find_key(key); idx < bookSize; idx++) + while (++idx < bookSize && (entry = read_entry(idx), entry.key == key)) { - read_entry(entry, idx); - if (entry.key != key) - break; - - unsigned score = entry.count; - - // If findBestMove is true choose highest rated book move - if (findBestMove) - { - if (score > bestScore) - { - bestScore = score; - bookMove = entry.move; - } - continue; - } + scoresSum += entry.count; // 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) + // high score it has higher probability to be choosen than a move + // with lower score. Note that first entry is always chosen. + if ( RKiss.rand() % scoresSum < entry.count + || (findBest && entry.count > bestScore)) bookMove = entry.move; + + if (entry.count > bestScore) + bestScore = entry.count; } + if (!bookMove) return MOVE_NONE; + // 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 promotion = (bookMove >> 12) & 7; + + if (promotion) + bookMove = make_promotion_move(move_from(Move(bookMove)), + move_to(Move(bookMove)), + PieceType(promotion + 1)); // Verify the book move is legal - MoveStack mlist[MOVES_MAX]; - MoveStack* last = generate_moves(pos, mlist); - for (MoveStack* cur = mlist; cur != last; cur++) - if ((int(cur->move) & 07777) == bookMove) - return cur->move; + for (MoveList ml(pos); !ml.end(); ++ml) + if (unsigned(ml.move() & ~(3 << 14)) == bookMove) // Mask out special flags + return ml.move(); return MOVE_NONE; } -/// 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 +/// Book::first_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 (leftmost) +/// 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::first_entry(uint64_t key) { int left, right, mid; - BookEntry entry; - // Binary search (finds the leftmost entry) + // Binary search (finds the leftmost entry with given key) left = 0; right = bookSize - 1; @@ -465,9 +480,7 @@ 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; @@ -475,111 +488,42 @@ int Book::find_key(uint64_t key) { assert(left == right); - read_entry(entry, left); - return entry.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. - -void Book::read_entry(BookEntry& 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(); - } + return read_entry(left).key == key ? left : bookSize; } -/// Book::read_integer() reads size chars from the file stream -/// and converts them in an integer number. +/// Book::operator>>() reads sizeof(T) chars from the file's binary byte +/// stream and converts them in a number of type T. +template +Book& Book::operator>>(T& n) { -uint64_t Book::read_integer(int size) { + n = 0; - char buf[8]; - uint64_t n = 0; + for (size_t i = 0; i < sizeof(T); i++) + n = T((n << 8) + bookFile.get()); - read(buf, size); - - // Numbers are stored on disk as a binary byte stream - for (int i = 0; i < size; i++) - n = (n << 8) + (unsigned char)buf[i]; - - return n; + return *this; } -//// -//// Local definitions -//// - -namespace { - - uint64_t book_key(const Position& pos) { - - uint64_t result = 0; - Bitboard b = pos.occupied_squares(); +/// Book::read_entry() takes an integer index, and returns the BookEntry +/// at the given index in the book file. - while (b) - { - Square s = pop_1st_bit(&b); - result ^= book_piece_key(pos.piece_on(s), s); - } - - result ^= book_castle_key(pos); - result ^= book_ep_key(pos); - result ^= book_color_key(pos); - return result; - } +BookEntry Book::read_entry(int idx) { + assert(idx >= 0 && idx < bookSize); + assert(bookFile.is_open()); - 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[PieceIdx + (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[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]; - - return result; - } - - - uint64_t book_ep_key(const Position& pos) { - - return pos.ep_square() == SQ_NONE ? 0 : Random64[EnPassantIdx + square_file(pos.ep_square())]; - } + BookEntry e; + bookFile.seekg(idx * sizeof(BookEntry), ios_base::beg); - uint64_t book_color_key(const Position& pos) { + *this >> e.key >> e.move >> e.count >> e.learn; - return pos.side_to_move() == WHITE ? Random64[TurnIdx] : 0; + if (!bookFile.good()) + { + cerr << "Failed to read book entry at index " << idx << endl; + exit(EXIT_FAILURE); } + return e; }