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https://github.com/sockspls/badfish
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107 lines
4 KiB
C++
107 lines
4 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
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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 "timeman.h"
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#include <algorithm>
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#include <cmath>
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#include "search.h"
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#include "uci.h"
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namespace Stockfish {
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TimeManagement Time; // Our global time management object
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// Called at the beginning of the search and calculates
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// the bounds of time allowed for the current game ply. We currently support:
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// 1) x basetime (+ z increment)
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// 2) x moves in y seconds (+ z increment)
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void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
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// If we have no time, no need to initialize TM, except for the start time,
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// which is used by movetime.
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startTime = limits.startTime;
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if (limits.time[us] == 0)
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return;
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TimePoint moveOverhead = TimePoint(Options["Move Overhead"]);
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TimePoint npmsec = TimePoint(Options["nodestime"]);
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// optScale is a percentage of available time to use for the current move.
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// maxScale is a multiplier applied to optimumTime.
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double optScale, maxScale;
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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: to avoid time losses, the given npmsec (nodes per millisecond)
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// must be much lower than the real engine speed.
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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 milliseconds to nodes
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limits.time[us] = TimePoint(availableNodes);
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limits.inc[us] *= npmsec;
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limits.npmsec = npmsec;
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}
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// Maximum move horizon of 50 moves
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int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
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// Make sure timeLeft is > 0 since we may use it as a divisor
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TimePoint timeLeft = std::max(TimePoint(1), limits.time[us] + limits.inc[us] * (mtg - 1)
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- moveOverhead * (2 + mtg));
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// Use extra time with larger increments
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double optExtra = std::clamp(1.0 + 12.5 * limits.inc[us] / limits.time[us], 1.0, 1.11);
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// Calculate time constants based on current time left.
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double optConstant = std::min(0.00334 + 0.0003 * std::log10(limits.time[us] / 1000.0), 0.0049);
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double maxConstant = std::max(3.4 + 3.0 * std::log10(limits.time[us] / 1000.0), 2.76);
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// x basetime (+ z increment)
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// If there is a healthy increment, timeLeft can exceed actual available
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// game time for the current move, so also cap to 20% of available game time.
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if (limits.movestogo == 0)
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{
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optScale = std::min(0.0120 + std::pow(ply + 3.1, 0.44) * optConstant,
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0.21 * limits.time[us] / double(timeLeft))
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* optExtra;
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maxScale = std::min(6.9, maxConstant + ply / 12.2);
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}
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// x moves in y seconds (+ z increment)
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else
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{
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optScale = std::min((0.88 + ply / 116.4) / mtg, 0.88 * limits.time[us] / double(timeLeft));
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maxScale = std::min(6.3, 1.5 + 0.11 * mtg);
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}
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// Limit the maximum possible time for this move
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optimumTime = TimePoint(optScale * timeLeft);
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maximumTime =
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TimePoint(std::min(0.84 * limits.time[us] - moveOverhead, maxScale * optimumTime)) - 10;
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if (Options["Ponder"])
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optimumTime += optimumTime / 4;
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}
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} // namespace Stockfish
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