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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
enum TimeType { OptimumTime, MaxTime };
- const int MoveHorizon = 50; // Plan time management at most this many moves ahead
- const double MaxRatio = 6.93; // When in trouble, we can step over reserved time with this ratio
- const double StealRatio = 0.36; // However we must not steal time from remaining moves over this ratio
+ constexpr int MoveHorizon = 50; // Plan time management at most this many moves ahead
+ constexpr double MaxRatio = 7.3; // When in trouble, we can step over reserved time with this ratio
+ constexpr double StealRatio = 0.34; // However we must not steal time from remaining moves over this ratio
// 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.
+ // Data was extracted from the CCRL game database with some simple filtering criteria.
double move_importance(int ply) {
- const double XScale = 8.27;
- const double XShift = 59.;
- const double Skew = 0.179;
+ constexpr double XScale = 6.85;
+ constexpr double XShift = 64.5;
+ constexpr double Skew = 0.171;
return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
}
template<TimeType T>
- int remaining(int myTime, int movesToGo, int ply, int slowMover)
- {
- const double TMaxRatio = (T == OptimumTime ? 1 : MaxRatio);
- const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
+ TimePoint remaining(TimePoint myTime, int movesToGo, int ply, TimePoint slowMover) {
+
+ constexpr double TMaxRatio = (T == OptimumTime ? 1.0 : MaxRatio);
+ constexpr double TStealRatio = (T == OptimumTime ? 0.0 : StealRatio);
- double moveImportance = (move_importance(ply) * slowMover) / 100;
- double otherMovesImportance = 0;
+ double moveImportance = (move_importance(ply) * slowMover) / 100.0;
+ double otherMovesImportance = 0.0;
for (int i = 1; i < movesToGo; ++i)
otherMovesImportance += move_importance(ply + 2 * i);
double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance);
double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance);
- return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks an explicit cast
+ return TimePoint(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast
}
} // namespace
/// 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 minThinkingTime = Options["Minimum Thinking Time"];
- int moveOverhead = Options["Move Overhead"];
- int slowMover = Options["Slow Mover"];
- int npmsec = Options["nodestime"];
+void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
+
+ TimePoint minThinkingTime = Options["Minimum Thinking Time"];
+ TimePoint moveOverhead = Options["Move Overhead"];
+ TimePoint slowMover = Options["Slow Mover"];
+ TimePoint npmsec = Options["nodestime"];
+ TimePoint hypMyTime;
// 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
- // real engine speed to avoid time losses.
+ // WARNING: to avoid time losses, the given npmsec (nodes per millisecond)
+ // must be much lower than the real engine speed.
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;
+ // Convert from milliseconds to nodes
+ limits.time[us] = TimePoint(availableNodes);
limits.inc[us] *= npmsec;
limits.npmsec = npmsec;
}
startTime = limits.startTime;
- unstablePvFactor = 1;
optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime);
- const int MaxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
+ const int maxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
- // We calculate optimum time usage for different hypothetical "moves to go"-values
+ // 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 (int hypMTG = 1; hypMTG <= MaxMTG; ++hypMTG)
+ for (int hypMTG = 1; hypMTG <= maxMTG; ++hypMTG)
{
// Calculate thinking time for hypothetical "moves to go"-value
- int hypMyTime = limits.time[us]
- + limits.inc[us] * (hypMTG - 1)
- - moveOverhead * (2 + std::min(hypMTG, 40));
+ hypMyTime = limits.time[us]
+ + limits.inc[us] * (hypMTG - 1)
+ - moveOverhead * (2 + std::min(hypMTG, 40));
- hypMyTime = std::max(hypMyTime, 0);
+ hypMyTime = std::max(hypMyTime, TimePoint(0));
- int t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
- int t2 = minThinkingTime + remaining<MaxTime >(hypMyTime, hypMTG, ply, slowMover);
+ TimePoint t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
+ TimePoint t2 = minThinkingTime + remaining<MaxTime >(hypMyTime, hypMTG, ply, slowMover);
optimumTime = std::min(t1, optimumTime);
maximumTime = std::min(t2, maximumTime);
projects / stockfish / blobdiff