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109 lines
2.6 KiB
C++
109 lines
2.6 KiB
C++
/*
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Texel - A UCI chess engine.
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Copyright (C) 2014 Peter Österlund, peterosterlund2@gmail.com
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This program 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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This program 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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/*
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* tbprobe.cpp
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*
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* Created on: Jun 2, 2014
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* Author: petero
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*/
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#include "tbprobe.hpp"
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#include "rtb-probe.hpp"
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#include "bitBoard.hpp"
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#include "position.hpp"
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#include "moveGen.hpp"
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#include <unordered_map>
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#include <cassert>
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static std::string currentRtbPath;
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void
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TBProbe::initialize(const std::string& rtbPath) {
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if (rtbPath != currentRtbPath) {
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Syzygy::init(rtbPath);
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currentRtbPath = rtbPath;
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}
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}
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bool
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TBProbe::rtbProbeDTZ(Position& pos, int& score) {
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const int nPieces = BitBoard::bitCount(pos.occupiedBB());
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if (nPieces > Syzygy::TBLargest)
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return false;
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if (pos.getCastleMask())
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return false;
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if (MoveGen::canTakeKing(pos))
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return false;
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int success;
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const int dtz = Syzygy::probe_dtz(pos, &success);
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if (!success)
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return false;
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if (dtz == 0) {
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score = 0;
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return true;
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}
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const int maxHalfMoveClock = std::abs(dtz) + pos.getHalfMoveClock();
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if (abs(dtz) <= 2) {
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if (maxHalfMoveClock > 101) {
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score = 0;
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return true;
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} else if (maxHalfMoveClock == 101)
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return false; // DTZ can be wrong when mate-in-1
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} else {
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if (maxHalfMoveClock > 100) {
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score = 0;
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return true;
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}
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}
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score = dtz;
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return true;
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}
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bool
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TBProbe::rtbProbeWDL(Position& pos, int& score) {
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if (BitBoard::bitCount(pos.occupiedBB()) > Syzygy::TBLargest)
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return false;
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if (pos.getCastleMask())
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return false;
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if (MoveGen::canTakeKing(pos))
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return false;
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int success;
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int wdl = Syzygy::probe_wdl(pos, &success);
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if (!success)
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return false;
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switch (wdl) {
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case 0: case 1: case -1:
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score = 0;
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break;
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case 2:
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score = 1;
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break;
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case -2:
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score = -1;
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break;
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default:
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return false;
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}
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return true;
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}
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