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113 lines
3.9 KiB
C++
113 lines
3.9 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) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
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Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, 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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#include <algorithm>
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#include "search.h"
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#include "timeman.h"
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#include "uci.h"
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TimeManagement Time; // Our global time management object
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namespace {
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enum TimeType { OptimumTime, MaxTime };
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int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
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int moveNum, bool ponder, TimeType type) {
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if (myTime <= 0)
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return 0;
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double ratio; // Which ratio of myTime we are going to use
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// Usage of increment follows quadratic distribution with the maximum at move 25
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double inc = myInc * std::max(55.0, 120 - 0.12 * (moveNum - 25) * (moveNum - 25));
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// In moves-to-go we distribute time according to a quadratic function with
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// the maximum around move 20 for 40 moves in y time case.
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if (movesToGo)
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{
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ratio = (type == OptimumTime ? 1.0 : 6.0) / std::min(50, movesToGo);
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if (moveNum <= 40)
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ratio *= 1.1 - 0.001 * (moveNum - 20) * (moveNum - 20);
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else
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ratio *= 1.5;
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ratio *= 1 + inc / (myTime * 8.5);
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}
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// Otherwise we increase usage of remaining time as the game goes on
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else
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{
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double k = 1 + 20 * moveNum / (500.0 + moveNum);
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ratio = (type == OptimumTime ? 0.017 : 0.07) * (k + inc / myTime);
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}
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int time = int(std::min(1.0, ratio) * std::max(0, myTime - moveOverhead));
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if (type == OptimumTime && ponder)
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time = 5 * time / 4;
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return time;
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}
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} // namespace
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/// init() is called at the beginning of the search and calculates the allowed
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/// thinking time out of the time control and current game ply. We support four
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/// different kinds of time controls, passed in 'limits':
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///
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/// inc == 0 && movestogo == 0 means: x basetime [sudden death!]
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/// inc == 0 && movestogo != 0 means: x moves in y minutes
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/// inc > 0 && movestogo == 0 means: x basetime + z increment
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/// inc > 0 && movestogo != 0 means: x moves in y minutes + z increment
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void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
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{
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int moveOverhead = Options["Move Overhead"];
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int npmsec = Options["nodestime"];
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bool ponder = Options["Ponder"];
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// If we have to play in 'nodes as time' mode, then convert from time
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// to nodes, and use resulting values in time management formulas.
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// WARNING: Given npms (nodes per millisecond) must be much lower then
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// the real engine speed to avoid time losses.
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if (npmsec)
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{
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if (!availableNodes) // Only once at game start
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availableNodes = npmsec * limits.time[us]; // Time is in msec
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// Convert from millisecs to nodes
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limits.time[us] = (int)availableNodes;
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limits.inc[us] *= npmsec;
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limits.npmsec = npmsec;
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}
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int moveNum = (ply + 1) / 2;
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startTime = limits.startTime;
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optimumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
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limits.movestogo, moveNum, ponder, OptimumTime);
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maximumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
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limits.movestogo, moveNum, ponder, MaxTime);
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}
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