/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, 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 <cfloat>
+#include <cassert>
#include <cmath>
+#include <cstdint>
#include "search.h"
-#include "timeman.h"
#include "ucioption.h"
-namespace {
-
- enum TimeType { OptimumTime, MaxTime };
-
- const int MoveHorizon = 50; // Plan time management at most this many moves ahead
- const double MaxRatio = 7.0; // When in trouble, we can step over reserved time with this ratio
- const double StealRatio = 0.33; // However we must not steal time from remaining moves over this ratio
-
- const double xscale = 9.3;
- const double xshift = 59.8;
- const double skewfactor = 0.172;
-
-
- // move_importance() is a skew-logistic function based on naive statistical
- // analysis of "how many games are still undecided after n half-moves". Game
- // is considered "undecided" as long as neither side has >275cp advantage.
- // Data was extracted from CCRL game database with some simple filtering criteria.
-
- double move_importance(int ply) {
-
- return pow((1 + exp((ply - xshift) / xscale)), -skewfactor) + DBL_MIN; // Ensure non-zero
- }
-
- template<TimeType T>
- int remaining(int myTime, int movesToGo, int currentPly, int slowMover)
- {
- const double TMaxRatio = (T == OptimumTime ? 1 : MaxRatio);
- const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
-
- double thisMoveImportance = (move_importance(currentPly) * slowMover) / 100;
- double otherMovesImportance = 0;
-
- for (int i = 1; i < movesToGo; ++i)
- otherMovesImportance += move_importance(currentPly + 2 * i);
-
- double ratio1 = (TMaxRatio * thisMoveImportance) / (TMaxRatio * thisMoveImportance + otherMovesImportance);
- double ratio2 = (thisMoveImportance + TStealRatio * otherMovesImportance) / (thisMoveImportance + otherMovesImportance);
-
- return int(floor(myTime * std::min(ratio1, ratio2)));
- }
+namespace Stockfish {
-} // namespace
+TimePoint TimeManagement::optimum() const { return optimumTime; }
+TimePoint TimeManagement::maximum() const { return maximumTime; }
+void TimeManagement::clear() {
+ availableNodes = -1; // When in 'nodes as time' mode
+}
-void TimeManager::init(const Search::LimitsType& limits, int currentPly, Color us)
-{
- /* We support four different kinds of time controls:
-
- increment == 0 && movesToGo == 0 means: x basetime [sudden death!]
- increment == 0 && movesToGo != 0 means: x moves in y minutes
- increment > 0 && movesToGo == 0 means: x basetime + z increment
- increment > 0 && movesToGo != 0 means: x moves in y minutes + z increment
-
- Time management is adjusted by following UCI parameters:
-
- emergencyMoveHorizon: Be prepared to always play at least this many moves
- emergencyBaseTime : Always attempt to keep at least this much time (in ms) at clock
- emergencyMoveTime : Plus attempt to keep at least this much time for each remaining emergency move
- minThinkingTime : No matter what, use at least this much thinking before doing the move
- */
-
- int hypMTG, hypMyTime, t1, t2;
-
- // Read uci parameters
- int emergencyMoveHorizon = Options["Emergency Move Horizon"];
- int emergencyBaseTime = Options["Emergency Base Time"];
- int emergencyMoveTime = Options["Emergency Move Time"];
- int minThinkingTime = Options["Minimum Thinking Time"];
- int slowMover = Options["Slow Mover"];
-
- // Initialize unstablePvFactor to 1 and search times to maximum values
- unstablePvFactor = 1;
- optimumSearchTime = maximumSearchTime = std::max(limits.time[us], minThinkingTime);
-
- // We calculate optimum time usage for different hypothetical "moves to go"-values and choose the
- // minimum of calculated search time values. Usually the greatest hypMTG gives the minimum values.
- for (hypMTG = 1; hypMTG <= (limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon); ++hypMTG)
- {
- // Calculate thinking time for hypothetical "moves to go"-value
- hypMyTime = limits.time[us]
- + limits.inc[us] * (hypMTG - 1)
- - emergencyBaseTime
- - emergencyMoveTime * std::min(hypMTG, emergencyMoveHorizon);
-
- hypMyTime = std::max(hypMyTime, 0);
-
- t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, currentPly, slowMover);
- t2 = minThinkingTime + remaining<MaxTime>(hypMyTime, hypMTG, currentPly, slowMover);
-
- optimumSearchTime = std::min(optimumSearchTime, t1);
- maximumSearchTime = std::min(maximumSearchTime, t2);
- }
-
- if (Options["Ponder"])
- optimumSearchTime += optimumSearchTime / 4;
+void TimeManagement::advance_nodes_time(std::int64_t nodes) {
+ assert(useNodesTime);
+ availableNodes = std::max(int64_t(0), availableNodes - nodes);
+}
- // Make sure that maxSearchTime is not over absoluteMaxSearchTime
- optimumSearchTime = std::min(optimumSearchTime, maximumSearchTime);
+// 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;
+ }
+
+ // 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;
+
+ // Maximum move horizon of 50 moves
+ int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
+
+ // If less than one second, gradually reduce mtg
+ if (scaledTime < 1000 && double(mtg) / scaledInc > 0.05)
+ {
+ mtg = scaledTime * 0.05;
+ }
+
+ // 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));
+
+ // 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);
+ }
+
+ // x moves in y seconds (+ z increment)
+ else
+ {
+ 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);
+ }
+
+ // 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