X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=2126741e717ae4fbb2cf1d14013d3d47f9d79c2f;hp=1350ddf97a5923e33c3f677bdef398df79154ea3;hb=c2048136ec73a1d4437d286d34539a05910d83d7;hpb=b1ac6c69a077c95c122a82d5b757adf9470fb308 diff --git a/src/position.cpp b/src/position.cpp index 1350ddf9..2126741e 100644 --- a/src/position.cpp +++ b/src/position.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) 2008-2009 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 @@ -25,7 +25,9 @@ #include #include #include +#include #include +#include #include "bitcount.h" #include "mersenne.h" @@ -38,18 +40,29 @@ #include "ucioption.h" using std::string; +using std::cout; +using std::endl; +struct PieceLetters : std::map { + + PieceLetters() { + + operator[]('K') = WK; operator[]('k') = BK; + operator[]('Q') = WQ; operator[]('q') = BQ; + operator[]('R') = WR; operator[]('r') = BR; + operator[]('B') = WB; operator[]('b') = BB; + operator[]('N') = WN; operator[]('n') = BN; + operator[]('P') = WP; operator[]('p') = BP; + } +}; //// //// Variables //// -int Position::castleRightsMask[64]; - Key Position::zobrist[2][8][64]; Key Position::zobEp[64]; Key Position::zobCastle[16]; -Key Position::zobMaterial[2][8][16]; Key Position::zobSideToMove; Key Position::zobExclusion; @@ -76,12 +89,36 @@ CheckInfo::CheckInfo(const Position& pos) { checkSq[KING] = EmptyBoardBB; } -Position::Position(const Position& pos) { - copy(pos); + +/// Position c'tors. Here we always create a copy of the original position +/// or the FEN string, we want the new born Position object do not depend +/// on any external data so we detach state pointer from the source one. + +Position::Position(int th) : threadID(th) {} + +Position::Position(const Position& pos, int th) { + + memcpy(this, &pos, sizeof(Position)); + detach(); // Always detach() in copy c'tor to avoid surprises + threadID = th; } -Position::Position(const string& fen) { +Position::Position(const string& fen, int th) { + from_fen(fen); + threadID = th; +} + + +/// Position::detach() copies the content of the current state and castling +/// masks inside the position itself. This is needed when the st pointee could +/// become stale, as example because the caller is about to going out of scope. + +void Position::detach() { + + startState = *st; + st = &startState; + st->previous = NULL; // as a safe guard } @@ -90,137 +127,101 @@ Position::Position(const string& fen) { /// correct (this is assumed to be the responsibility of the GUI). void Position::from_fen(const string& fen) { +/* + A FEN string defines a particular position using only the ASCII character set. - static const string pieceLetters = "KQRBNPkqrbnp"; - static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP }; + A FEN string contains six fields. The separator between fields is a space. The fields are: - clear(); + 1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending + with rank 1; within each rank, the contents of each square are described from file a through file h. + Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken + from the standard English names. White pieces are designated using upper-case letters ("PNBRQK") + while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number + of blank squares), and "/" separate ranks. - // Board + 2) Active color. "w" means white moves next, "b" means black. + + 3) Castling availability. If neither side can castle, this is "-". Otherwise, this has one or more + letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle + kingside), and/or "q" (Black can castle queenside). + + 4) En passant target square in algebraic notation. If there's no en passant target square, this is "-". + If a pawn has just made a 2-square move, this is the position "behind" the pawn. This is recorded + regardless of whether there is a pawn in position to make an en passant capture. + + 5) Halfmove clock: This is the number of halfmoves since the last pawn advance or capture. This is used + to determine if a draw can be claimed under the fifty-move rule. + + 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move. +*/ + + static PieceLetters pieceLetters; + + char token; + std::istringstream ss(fen); Rank rank = RANK_8; File file = FILE_A; - size_t i = 0; - for ( ; fen[i] != ' '; i++) + + clear(); + + // 1. Piece placement field + while (ss.get(token) && token != ' ') { - if (isdigit(fen[i])) + if (isdigit(token)) { - // Skip the given number of files - file += (fen[i] - '1' + 1); + file += token - '0'; // Skip the given number of files continue; } - else if (fen[i] == '/') + else if (token == '/') { file = FILE_A; rank--; continue; } - size_t idx = pieceLetters.find(fen[i]); - if (idx == string::npos) - { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - Square square = make_square(file, rank); - put_piece(pieces[idx], square); + + if (pieceLetters.find(token) == pieceLetters.end()) + goto incorrect_fen; + + put_piece(pieceLetters[token], make_square(file, rank)); file++; } - // Side to move - i++; - if (fen[i] != 'w' && fen[i] != 'b') - { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - sideToMove = (fen[i] == 'w' ? WHITE : BLACK); + // 2. Active color + if (!ss.get(token) || (token != 'w' && token != 'b')) + goto incorrect_fen; - // Castling rights - i++; - if (fen[i] != ' ') + sideToMove = (token == 'w' ? WHITE : BLACK); + + if (!ss.get(token) || token != ' ') + goto incorrect_fen; + + // 3. Castling availability + while (ss.get(token) && token != ' ') { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } + if (token == '-') + continue; - i++; - while (strchr("KQkqabcdefghABCDEFGH-", fen[i])) { - if (fen[i] == '-') - { - i++; - break; - } - else if (fen[i] == 'K') allow_oo(WHITE); - else if (fen[i] == 'Q') allow_ooo(WHITE); - else if (fen[i] == 'k') allow_oo(BLACK); - else if (fen[i] == 'q') allow_ooo(BLACK); - else if (fen[i] >= 'A' && fen[i] <= 'H') { - File rookFile, kingFile = FILE_NONE; - for (Square square = SQ_B1; square <= SQ_G1; square++) - if (piece_on(square) == WK) - kingFile = square_file(square); - if (kingFile == FILE_NONE) { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - initialKFile = kingFile; - rookFile = File(fen[i] - 'A') + FILE_A; - if (rookFile < initialKFile) { - allow_ooo(WHITE); - initialQRFile = rookFile; - } - else { - allow_oo(WHITE); - initialKRFile = rookFile; - } - } - else if (fen[i] >= 'a' && fen[i] <= 'h') { - File rookFile, kingFile = FILE_NONE; - for (Square square = SQ_B8; square <= SQ_G8; square++) - if (piece_on(square) == BK) - kingFile = square_file(square); - if (kingFile == FILE_NONE) { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - initialKFile = kingFile; - rookFile = File(fen[i] - 'a') + FILE_A; - if (rookFile < initialKFile) { - allow_ooo(BLACK); - initialQRFile = rookFile; - } - else { - allow_oo(BLACK); - initialKRFile = rookFile; - } - } - else { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - i++; + if (!set_castling_rights(token)) + goto incorrect_fen; } - // Skip blanks - while (fen[i] == ' ') - i++; - - // En passant square -- ignore if no capture is possible - if ( i <= fen.length() - 2 - && (fen[i] >= 'a' && fen[i] <= 'h') - && (fen[i+1] == '3' || fen[i+1] == '6')) + // 4. En passant square -- ignore if no capture is possible + char col, row; + if ( (ss.get(col) && (col >= 'a' && col <= 'h')) + && (ss.get(row) && (row == '3' || row == '6'))) { - Square fenEpSquare = square_from_string(fen.substr(i, 2)); + Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row)); Color them = opposite_color(sideToMove); - if (attacks_from(fenEpSquare, them) & this->pieces(PAWN, sideToMove)) - st->epSquare = square_from_string(fen.substr(i, 2)); + + if (attacks_from(fenEpSquare, them) & pieces(PAWN, sideToMove)) + st->epSquare = fenEpSquare; } - // Various initialisation - for (Square sq = SQ_A1; sq <= SQ_H8; sq++) - castleRightsMask[sq] = ALL_CASTLES; + // 5-6. Halfmove clock and fullmove number are not parsed - castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO|WHITE_OOO); - castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO|BLACK_OOO); + // Various initialisations + castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO; + castleRightsMask[make_square(initialKFile, RANK_8)] ^= BLACK_OO | BLACK_OOO; castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO; castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO; castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO; @@ -234,6 +235,67 @@ void Position::from_fen(const string& fen) { st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); + return; + +incorrect_fen: + cout << "Error in FEN string: " << fen << endl; +} + + +/// Position::set_castling_rights() sets castling parameters castling avaiability. +/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN +/// that uses the letters of the columns on which the rooks began the game instead +/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is +/// associated with the castling right, the traditional castling tag will be replaced +/// by the file letter of the involved rook as for the Shredder-FEN. + +bool Position::set_castling_rights(char token) { + + Color c = token >= 'a' ? BLACK : WHITE; + Square sqA = (c == WHITE ? SQ_A1 : SQ_A8); + Square sqH = (c == WHITE ? SQ_H1 : SQ_H8); + Piece rook = (c == WHITE ? WR : BR); + + initialKFile = square_file(king_square(c)); + token = char(toupper(token)); + + if (token == 'K') + { + for (Square sq = sqH; sq >= sqA; sq--) + if (piece_on(sq) == rook) + { + allow_oo(c); + initialKRFile = square_file(sq); + break; + } + } + else if (token == 'Q') + { + for (Square sq = sqA; sq <= sqH; sq++) + if (piece_on(sq) == rook) + { + allow_ooo(c); + initialQRFile = square_file(sq); + break; + } + } + else if (token >= 'A' && token <= 'H') + { + File rookFile = File(token - 'A') + FILE_A; + if (rookFile < initialKFile) + { + allow_ooo(c); + initialQRFile = rookFile; + } + else + { + allow_oo(c); + initialKRFile = rookFile; + } + } + else return false; + + return true; } @@ -316,15 +378,16 @@ void Position::print(Move m) const { RequestPending = true; - std::cout << std::endl; + cout << endl; if (m != MOVE_NONE) { + Position p(*this, thread()); string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); - std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl; + cout << "Move is: " << col << move_to_san(p, m) << endl; } for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; + cout << "+---+---+---+---+---+---+---+---+" << endl; for (File file = FILE_A; file <= FILE_H; file++) { Square sq = make_square(file, rank); @@ -333,27 +396,18 @@ void Position::print(Move m) const { piece = NO_PIECE; char col = (color_of_piece_on(sq) == BLACK ? '=' : ' '); - std::cout << '|' << col << pieceLetters[piece] << col; + cout << '|' << col << pieceLetters[piece] << col; } - std::cout << '|' << std::endl; + cout << '|' << endl; } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl - << "Fen is: " << to_fen() << std::endl - << "Key is: " << st->key << std::endl; + cout << "+---+---+---+---+---+---+---+---+" << endl + << "Fen is: " << to_fen() << endl + << "Key is: " << st->key << endl; RequestPending = false; } -/// Position::copy() creates a copy of the input position. - -void Position::copy(const Position& pos) { - - memcpy(this, &pos, sizeof(Position)); - saveState(); // detach and copy state info -} - - /// Position:hidden_checkers<>() returns a bitboard of all pinned (against the /// king) pieces for the given color and for the given pinner type. Or, when /// template parameter FindPinned is false, the pieces of the given color @@ -628,10 +682,10 @@ bool Position::move_is_check(Move m, const CheckInfo& ci) const { } } - // En passant capture with check? We have already handled the case + // En passant capture with check ? We have already handled the case // of direct checks and ordinary discovered check, the only case we - // need to handle is the unusual case of a discovered check through the - // captured pawn. + // need to handle is the unusual case of a discovered check through + // the captured pawn. if (move_is_ep(m)) { Square capsq = make_square(square_file(to), square_rank(from)); @@ -683,14 +737,14 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI assert(is_ok()); assert(move_is_ok(m)); - Bitboard key = st->key; + Key key = st->key; // Copy some fields of old state to our new StateInfo object except the // ones which are recalculated from scratch anyway, then switch our state // pointer to point to the new, ready to be updated, state. struct ReducedStateInfo { Key pawnKey, materialKey; - int castleRights, rule50, pliesFromNull; + int castleRights, rule50, gamePly, pliesFromNull; Square epSquare; Score value; Value npMaterial[2]; @@ -702,8 +756,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = key; - gamePly++; + history[st->gamePly++] = key; // Update side to move key ^= zobSideToMove; @@ -760,7 +813,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI } // Prefetch TT access as soon as we know key is updated - TT.prefetch(key); + prefetch((char*)TT.first_entry(key)); // Move the piece Bitboard move_bb = make_move_bb(from, to); @@ -795,6 +848,46 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI key ^= zobEp[st->epSquare]; } } + + if (pm) // promotion ? + { + PieceType promotion = move_promotion_piece(m); + + assert(promotion >= KNIGHT && promotion <= QUEEN); + + // Insert promoted piece instead of pawn + clear_bit(&(byTypeBB[PAWN]), to); + set_bit(&(byTypeBB[promotion]), to); + board[to] = piece_of_color_and_type(us, promotion); + + // Update piece counts + pieceCount[us][promotion]++; + pieceCount[us][PAWN]--; + + // Update material key + st->materialKey ^= zobrist[us][PAWN][pieceCount[us][PAWN]]; + st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]-1]; + + // Update piece lists, move the last pawn at index[to] position + // and shrink the list. Add a new promotion piece to the list. + Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]]; + index[lastPawnSquare] = index[to]; + pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare; + pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; + index[to] = pieceCount[us][promotion] - 1; + pieceList[us][promotion][index[to]] = to; + + // Partially revert hash keys update + key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; + st->pawnKey ^= zobrist[us][PAWN][to]; + + // Partially revert and update incremental scores + st->value -= pst(us, PAWN, to); + st->value += pst(us, promotion, to); + + // Update material + st->npMaterial[us] += piece_value_midgame(promotion); + } } // Update incremental scores @@ -803,46 +896,6 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Set capture piece st->capture = capture; - if (pm) // promotion ? - { - PieceType promotion = move_promotion_piece(m); - - assert(promotion >= KNIGHT && promotion <= QUEEN); - - // Insert promoted piece instead of pawn - clear_bit(&(byTypeBB[PAWN]), to); - set_bit(&(byTypeBB[promotion]), to); - board[to] = piece_of_color_and_type(us, promotion); - - // Update material key - st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; - st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; - - // Update piece counts - pieceCount[us][PAWN]--; - pieceCount[us][promotion]++; - - // Update piece lists, move the last pawn at index[to] position - // and shrink the list. Add a new promotion piece to the list. - Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]]; - index[lastPawnSquare] = index[to]; - pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare; - pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; - index[to] = pieceCount[us][promotion] - 1; - pieceList[us][promotion][index[to]] = to; - - // Partially revert hash keys update - key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; - st->pawnKey ^= zobrist[us][PAWN][to]; - - // Partially revert and update incremental scores - st->value -= pst(us, PAWN, to); - st->value += pst(us, promotion, to); - - // Update material - st->npMaterial[us] += piece_value_midgame(promotion); - } - // Update the key with the final value st->key = key; @@ -882,23 +935,31 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI /// Position::do_capture_move() is a private method used to update captured /// piece info. It is called from the main Position::do_move function. -void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Square to, bool ep) { +void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) { assert(capture != KING); Square capsq = to; - if (ep) // en passant ? + // If the captured piece was a pawn, update pawn hash key, + // otherwise update non-pawn material. + if (capture == PAWN) { - capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S); + if (ep) // en passant ? + { + capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S); - assert(to == st->epSquare); - assert(relative_rank(opposite_color(them), to) == RANK_6); - assert(piece_on(to) == EMPTY); - assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); + assert(to == st->epSquare); + assert(relative_rank(opposite_color(them), to) == RANK_6); + assert(piece_on(to) == EMPTY); + assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); - board[capsq] = EMPTY; + board[capsq] = EMPTY; + } + st->pawnKey ^= zobrist[them][PAWN][capsq]; } + else + st->npMaterial[them] -= piece_value_midgame(capture); // Remove captured piece clear_bit(&(byColorBB[them]), capsq); @@ -911,19 +972,12 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ // Update incremental scores st->value -= pst(them, capture, capsq); - // If the captured piece was a pawn, update pawn hash key, - // otherwise update non-pawn material. - if (capture == PAWN) - st->pawnKey ^= zobrist[them][PAWN][capsq]; - else - st->npMaterial[them] -= piece_value_midgame(capture); - - // Update material hash key - st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]]; - // Update piece count pieceCount[them][capture]--; + // Update material hash key + st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + // Update piece list, move the last piece at index[capsq] position // // WARNING: This is a not perfectly revresible operation. When we @@ -1047,7 +1101,6 @@ void Position::undo_move(Move m) { assert(is_ok()); assert(move_is_ok(m)); - gamePly--; sideToMove = opposite_color(sideToMove); if (move_is_castle(m)) @@ -1097,7 +1150,6 @@ void Position::undo_move(Move m) { pieceList[us][PAWN][index[to]] = to; } - // Put the piece back at the source square Bitboard move_bb = make_move_bb(to, from); do_move_bb(&(byColorBB[us]), move_bb); @@ -1232,21 +1284,20 @@ void Position::do_null_move(StateInfo& backupSt) { // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = st->key; + history[st->gamePly++] = st->key; // Update the necessary information if (st->epSquare != SQ_NONE) st->key ^= zobEp[st->epSquare]; st->key ^= zobSideToMove; - TT.prefetch(st->key); + prefetch((char*)TT.first_entry(st->key)); sideToMove = opposite_color(sideToMove); st->epSquare = SQ_NONE; st->rule50++; st->pliesFromNull = 0; st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; - gamePly++; } @@ -1268,7 +1319,7 @@ void Position::undo_null_move() { // Update the necessary information sideToMove = opposite_color(sideToMove); st->rule50--; - gamePly--; + st->gamePly--; } @@ -1297,11 +1348,11 @@ int Position::see_sign(Move m) const { Square from = move_from(m); Square to = move_to(m); - // Early return if SEE cannot be negative because capturing piece value - // is not bigger then captured one. - if ( midgame_value_of_piece_on(from) <= midgame_value_of_piece_on(to) - && type_of_piece_on(from) != KING) - return 1; + // Early return if SEE cannot be negative because captured piece value + // is not less then capturing one. Note that king moves always return + // here because king midgame value is set to 0. + if (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from)) + return 1; return see(from, to); } @@ -1443,19 +1494,6 @@ int Position::see(Square from, Square to) const { } -/// Position::saveState() copies the content of the current state -/// inside startState and makes st point to it. This is needed -/// when the st pointee could become stale, as example because -/// the caller is about to going out of scope. - -void Position::saveState() { - - startState = *st; - st = &startState; - st->previous = NULL; // as a safe guard -} - - /// Position::clear() erases the position object to a pristine state, with an /// empty board, white to move, and no castling rights. @@ -1477,8 +1515,10 @@ void Position::clear() { for (int j = 0; j < 16; j++) pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; + for (Square sq = SQ_A1; sq <= SQ_H8; sq++) + castleRightsMask[sq] = ALL_CASTLES; + sideToMove = WHITE; - gamePly = 0; initialKFile = FILE_E; initialKRFile = FILE_H; initialQRFile = FILE_A; @@ -1493,7 +1533,7 @@ void Position::clear() { void Position::reset_game_ply() { - gamePly = 0; + st->gamePly = 0; } @@ -1597,8 +1637,8 @@ Key Position::compute_material_key() const { for (PieceType pt = PAWN; pt <= QUEEN; pt++) { int count = piece_count(c, pt); - for (int i = 0; i <= count; i++) - result ^= zobMaterial[c][pt][i]; + for (int i = 0; i < count; i++) + result ^= zobrist[c][pt][i]; } return result; } @@ -1657,6 +1697,7 @@ Value Position::compute_non_pawn_material(Color c) const { /// Position::is_draw() tests whether the position is drawn by material, /// repetition, or the 50 moves rule. It does not detect stalemates, this /// must be done by the search. +// FIXME: Currently we are not handling 50 move rule correctly when in check bool Position::is_draw() const { @@ -1670,8 +1711,8 @@ bool Position::is_draw() const { return true; // Draw by repetition? - for (int i = 2; i < Min(Min(gamePly, st->rule50), st->pliesFromNull); i += 2) - if (history[gamePly - i] == st->key) + for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2) + if (history[st->gamePly - i] == st->key) return true; return false; @@ -1750,35 +1791,22 @@ void Position::init_zobrist() { zobCastle[i] = genrand_int64(); zobSideToMove = genrand_int64(); - - for (int i = 0; i < 2; i++) - for (int j = 0; j < 8; j++) - for (int k = 0; k < 16; k++) - zobMaterial[i][j][k] = (k > 0)? Key(genrand_int64()) : Key(0LL); - - for (int i = 0; i < 16; i++) - zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL); - zobExclusion = genrand_int64(); } /// Position::init_piece_square_tables() initializes the piece square tables. -/// This is a two-step operation: First, the white halves of the tables are -/// copied from the MgPST[][] and EgPST[][] arrays, with a small random number -/// added to each entry if the "Randomness" UCI parameter is non-zero. +/// This is a two-step operation: +/// First, the white halves of the tables are +/// copied from the MgPST[][] and EgPST[][] arrays. /// Second, the black halves of the tables are initialized by mirroring /// and changing the sign of the corresponding white scores. void Position::init_piece_square_tables() { - int r = get_option_value_int("Randomness"), i; for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = WP; p <= WK; p++) - { - i = (r == 0)? 0 : (genrand_int32() % (r*2) - r); - PieceSquareTable[p][s] = make_score(MgPST[p][s] + i, EgPST[p][s] + i); - } + PieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]); for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = BP; p <= BK; p++) @@ -1795,6 +1823,7 @@ void Position::flipped_copy(const Position& pos) { assert(pos.is_ok()); clear(); + threadID = pos.thread(); // Board for (Square s = SQ_A1; s <= SQ_H8; s++) @@ -1814,9 +1843,6 @@ void Position::flipped_copy(const Position& pos) { initialKRFile = pos.initialKRFile; initialQRFile = pos.initialQRFile; - for (Square sq = SQ_A1; sq <= SQ_H8; sq++) - castleRightsMask[sq] = ALL_CASTLES; - castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO | WHITE_OOO); castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO | BLACK_OOO); castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;