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https://github.com/HChaZZY/Stockfish.git
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ecd07e51d0
1/ eval margin and gains removed: - gains removed by Value(128): search() and qsearch() now behave consistently! 2/ futility_margin() - testing showed that there is no added value in this weird (log(depth), movecount) formula, and a much simpler linear formula is just as good. In fact, it is most likely better, as it is not yet optimally tuned. - the new simplified formula also means we get rid of FutilityMargins[], its initialization code, and more importantly ss->futilityMoveCount, and the hacky code that updates it throughout the search(). - the current formula gives negative futility margins, and there is a hidden interaction between the move coutn pruning formula and the futility margin one: what happens is that MCP is supposed to be triggered before we use the non-sensical negative futility margins. 3/ unify pre & post futility pruning - pre futility pruning (what SF calls value based pruning) used depth < 7 plies, while post futility pruning (what SF calls static null move pruning) used depth < 4 plies. - also the condition depth < 7 in pre futility pruning was not obvious, and it seemd to be depth < 16 (futility_margin() returns an infinite value when depth >= 7). Tested with fixed number of games both at short TC: ELO: 0.82 +-2.1 (95%) LOS: 77.3% Total: 40000 W: 7939 L: 7845 D: 24216 And long TC ELO: 0.59 +-2.0 (95%) LOS: 71.9% Total: 40000 W: 6876 L: 6808 D: 26316 bench: 10206576
112 lines
3.3 KiB
C++
112 lines
3.3 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef SEARCH_H_INCLUDED
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#define SEARCH_H_INCLUDED
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#include <cstring>
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#include <memory>
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#include <stack>
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#include <vector>
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#include "misc.h"
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#include "position.h"
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#include "types.h"
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struct SplitPoint;
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namespace Search {
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/// The Stack struct keeps track of the information we need to remember from
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/// nodes shallower and deeper in the tree during the search. Each search thread
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/// has its own array of Stack objects, indexed by the current ply.
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struct Stack {
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SplitPoint* splitPoint;
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int ply;
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Move currentMove;
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Move excludedMove;
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Move killers[2];
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Depth reduction;
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Value staticEval;
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int skipNullMove;
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int futilityMoveCount;
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};
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/// RootMove struct is used for moves at the root of the tree. For each root
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/// move we store a score, a node count, and a PV (really a refutation in the
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/// case of moves which fail low). Score is normally set at -VALUE_INFINITE for
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/// all non-pv moves.
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struct RootMove {
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RootMove(Move m) : score(-VALUE_INFINITE), prevScore(-VALUE_INFINITE) {
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pv.push_back(m); pv.push_back(MOVE_NONE);
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}
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bool operator<(const RootMove& m) const { return score > m.score; } // Ascending sort
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bool operator==(const Move& m) const { return pv[0] == m; }
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void extract_pv_from_tt(Position& pos);
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void insert_pv_in_tt(Position& pos);
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Value score;
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Value prevScore;
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std::vector<Move> pv;
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};
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/// The LimitsType struct stores information sent by GUI about available time
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/// to search the current move, maximum depth/time, if we are in analysis mode
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/// or if we have to ponder while is our opponent's side to move.
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struct LimitsType {
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LimitsType() { std::memset(this, 0, sizeof(LimitsType)); }
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bool use_time_management() const { return !(mate | movetime | depth | nodes | infinite); }
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int time[COLOR_NB], inc[COLOR_NB], movestogo, depth, nodes, movetime, mate, infinite, ponder;
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};
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/// The SignalsType struct stores volatile flags updated during the search
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/// typically in an async fashion, for instance to stop the search by the GUI.
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struct SignalsType {
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bool stopOnPonderhit, firstRootMove, stop, failedLowAtRoot;
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};
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typedef std::auto_ptr<std::stack<StateInfo> > StateStackPtr;
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extern volatile SignalsType Signals;
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extern LimitsType Limits;
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extern std::vector<RootMove> RootMoves;
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extern Position RootPos;
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extern Color RootColor;
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extern Time::point SearchTime;
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extern StateStackPtr SetupStates;
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extern void init();
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extern size_t perft(Position& pos, Depth depth);
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extern void think();
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} // namespace Search
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#endif // #ifndef SEARCH_H_INCLUDED
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