Subversion Repositories Games.Chess Giants

/*

  Stockfish, a UCI chess playing engine derived from Glaurung 2.1

  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)

  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad

  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License

  along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef SEARCH_H_INCLUDED

#define SEARCH_H_INCLUDED

#include <vector>

#include "misc.h"

#include "movepick.h"

#include "types.h"

class Position;

namespace Search {

/// Threshold used for countermoves based pruning

const int CounterMovePruneThreshold = 0;

/// Stack struct keeps track of the information we need to remember from nodes

/// shallower and deeper in the tree during the search. Each search thread has

/// its own array of Stack objects, indexed by the current ply.

struct Stack {

  Move* pv;

  PieceToHistory* contHistory;

  int ply;

  Move currentMove;

  Move excludedMove;

  Move killers[2];

  Value staticEval;

  int statScore;

  int moveCount;

};

/// RootMove struct is used for moves at the root of the tree. For each root move

/// we store a score and a PV (really a refutation in the case of moves which

/// fail low). Score is normally set at -VALUE_INFINITE for all non-pv moves.

struct RootMove {

  explicit RootMove(Move m) : pv(1, m) {}

  bool extract_ponder_from_tt(Position& pos);

  bool operator==(const Move& m) const { return pv[0] == m; }

  bool operator<(const RootMove& m) const { // Sort in descending order

    return m.score != score ? m.score < score

                            : m.previousScore < previousScore;

  }

  Value score = -VALUE_INFINITE;

  Value previousScore = -VALUE_INFINITE;

  int selDepth = 0;

  std::vector<Move> pv;

};

typedef std::vector<RootMove> RootMoves;

/// LimitsType struct stores information sent by GUI about available time to

/// search the current move, maximum depth/time, or if we are in analysis mode.

struct LimitsType {

  LimitsType() { // Init explicitly due to broken value-initialization of non POD in MSVC

    nodes = time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] =

    npmsec = movestogo = depth = movetime = mate = perft = infinite = 0;

  }

  bool use_time_management() const {

    return !(mate | movetime | depth | nodes | perft | infinite);

  }

  std::vector<Move> searchmoves;

  int time[COLOR_NB], inc[COLOR_NB], npmsec, movestogo, depth,

      movetime, mate, perft, infinite;

  int64_t nodes;

  TimePoint startTime;

};

extern LimitsType Limits;

void init();

void clear();

} // namespace Search

#endif // #ifndef SEARCH_H_INCLUDED