/*
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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include "timeman.h"
+
#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <cstdint>
#include "search.h"
-#include "timeman.h"
-#include "uci.h"
+#include "ucioption.h"
-TimeManagement Time; // Our global time management object
+namespace Stockfish {
-namespace {
+TimePoint TimeManagement::optimum() const { return optimumTime; }
+TimePoint TimeManagement::maximum() const { return maximumTime; }
- enum TimeType { OptimumTime, MaxTime };
+void TimeManagement::clear() {
+ availableNodes = -1; // When in 'nodes as time' mode
+}
- int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
- int moveNum, bool ponder, TimeType type) {
+void TimeManagement::advance_nodes_time(std::int64_t nodes) {
+ assert(useNodesTime);
+ availableNodes = std::max(int64_t(0), availableNodes - nodes);
+}
- if (myTime <= 0)
- return 0;
+// Called at the beginning of the search and calculates
+// the bounds of time allowed for the current game ply. We currently support:
+// 1) x basetime (+ z increment)
+// 2) x moves in y seconds (+ z increment)
+void TimeManagement::init(Search::LimitsType& limits,
+ Color us,
+ int ply,
+ const OptionsMap& options,
+ double& originalTimeAdjust) {
+ TimePoint npmsec = TimePoint(options["nodestime"]);
+
+ // If we have no time, we don't need to fully initialize TM.
+ // startTime is used by movetime and useNodesTime is used in elapsed calls.
+ startTime = limits.startTime;
+ useNodesTime = npmsec != 0;
+
+ if (limits.time[us] == 0)
+ return;
+
+ TimePoint moveOverhead = TimePoint(options["Move Overhead"]);
+
+ // optScale is a percentage of available time to use for the current move.
+ // maxScale is a multiplier applied to optimumTime.
+ double optScale, maxScale;
+
+ // If we have to play in 'nodes as time' mode, then convert from time
+ // to nodes, and use resulting values in time management formulas.
+ // WARNING: to avoid time losses, the given npmsec (nodes per millisecond)
+ // must be much lower than the real engine speed.
+ if (useNodesTime)
+ {
+ if (availableNodes == -1) // Only once at game start
+ availableNodes = npmsec * limits.time[us]; // Time is in msec
+
+ // Convert from milliseconds to nodes
+ limits.time[us] = TimePoint(availableNodes);
+ limits.inc[us] *= npmsec;
+ limits.npmsec = npmsec;
+ moveOverhead *= npmsec;
+ }
- double ratio; // Which ratio of myTime we are going to use
+ // These numbers are used where multiplications, divisions or comparisons
+ // with constants are involved.
+ const int64_t scaleFactor = useNodesTime ? npmsec : 1;
+ const TimePoint scaledTime = limits.time[us] / scaleFactor;
+ const TimePoint scaledInc = limits.inc[us] / scaleFactor;
- // Usage of increment follows quadratic distribution with the maximum at move 25
- double inc = myInc * std::max(55.0, 120 - 0.12 * (moveNum - 25) * (moveNum - 25));
+ // Maximum move horizon of 50 moves
+ int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
- // In moves-to-go we distribute time according to a quadratic function with
- // the maximum around move 20 for 40 moves in y time case.
- if (movesToGo)
+ // If less than one second, gradually reduce mtg
+ if (scaledTime < 1000 && double(mtg) / scaledInc > 0.05)
{
- ratio = (type == OptimumTime ? 1.0 : 6.0) / std::min(50, movesToGo);
+ mtg = scaledTime * 0.05;
+ }
- if (moveNum <= 40)
- ratio *= 1.1 - 0.001 * (moveNum - 20) * (moveNum - 20);
- else
- ratio *= 1.5;
+ // Make sure timeLeft is > 0 since we may use it as a divisor
+ TimePoint timeLeft = std::max(TimePoint(1), limits.time[us] + limits.inc[us] * (mtg - 1)
+ - moveOverhead * (2 + mtg));
- ratio *= 1 + inc / (myTime * 8.5);
+ // x basetime (+ z increment)
+ // If there is a healthy increment, timeLeft can exceed the actual available
+ // game time for the current move, so also cap to a percentage of available game time.
+ if (limits.movestogo == 0)
+ {
+ // Extra time according to timeLeft
+ if (originalTimeAdjust < 0)
+ originalTimeAdjust = 0.3285 * std::log10(timeLeft) - 0.4830;
+
+ // Calculate time constants based on current time left.
+ double logTimeInSec = std::log10(scaledTime / 1000.0);
+ double optConstant = std::min(0.00308 + 0.000319 * logTimeInSec, 0.00506);
+ double maxConstant = std::max(3.39 + 3.01 * logTimeInSec, 2.93);
+
+ optScale = std::min(0.0122 + std::pow(ply + 2.95, 0.462) * optConstant,
+ 0.213 * limits.time[us] / timeLeft)
+ * originalTimeAdjust;
+
+ maxScale = std::min(6.64, maxConstant + ply / 12.0);
}
- // Otherwise we increase usage of remaining time as the game goes on
+
+ // x moves in y seconds (+ z increment)
else
{
- double k = 1 + 20 * moveNum / (500.0 + moveNum);
- ratio = (type == OptimumTime ? 0.017 : 0.07) * (k + inc / myTime);
+ optScale = std::min((0.88 + ply / 116.4) / mtg, 0.88 * limits.time[us] / timeLeft);
+ maxScale = std::min(6.3, 1.5 + 0.11 * mtg);
}
- int time = int(std::min(1.0, ratio) * std::max(0, myTime - moveOverhead));
-
- if (type == OptimumTime && ponder)
- time *= 1.25;
-
- if (type == MaxTime)
- time -= 10; // Keep always at least 10 millisecs on the clock
-
- return std::max(0, time);
- }
-
-} // namespace
-
-
-/// init() is called at the beginning of the search and calculates the allowed
-/// thinking time out of the time control and current game ply. We support four
-/// different kinds of time controls, passed in 'limits':
-///
-/// inc == 0 && movestogo == 0 means: x basetime [sudden death!]
-/// inc == 0 && movestogo != 0 means: x moves in y minutes
-/// inc > 0 && movestogo == 0 means: x basetime + z increment
-/// inc > 0 && movestogo != 0 means: x moves in y minutes + z increment
-
-void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
-{
- int moveOverhead = Options["Move Overhead"];
- int npmsec = Options["nodestime"];
- bool ponder = Options["Ponder"];
-
- // If we have to play in 'nodes as time' mode, then convert from time
- // to nodes, and use resulting values in time management formulas.
- // WARNING: Given npms (nodes per millisecond) must be much lower then
- // the real engine speed to avoid time losses.
- if (npmsec)
- {
- if (!availableNodes) // Only once at game start
- availableNodes = npmsec * limits.time[us]; // Time is in msec
-
- // Convert from millisecs to nodes
- limits.time[us] = (int)availableNodes;
- limits.inc[us] *= npmsec;
- limits.npmsec = npmsec;
- }
-
- int moveNum = (ply + 1) / 2;
-
- startTime = limits.startTime;
- optimumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
- limits.movestogo, moveNum, ponder, OptimumTime);
- maximumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
- limits.movestogo, moveNum, ponder, MaxTime);
+ // Limit the maximum possible time for this move
+ optimumTime = TimePoint(optScale * timeLeft);
+ maximumTime =
+ TimePoint(std::min(0.825 * limits.time[us] - moveOverhead, maxScale * optimumTime)) - 10;
+
+ if (options["Ponder"])
+ optimumTime += optimumTime / 4;
}
+
+} // namespace Stockfish
projects / stockfish / blobdiff