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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2017 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
*/
#include <algorithm>
-#include <cfloat>
-#include <cmath>
#include "search.h"
#include "timeman.h"
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
+ int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
+ int ply, bool ponder, TimeType type) {
+ if (myTime <= 0)
+ return 0;
- // 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.
+ int moveNumber = (ply + 1) / 2;
+ double ratio; // Which ratio of myTime we are going to use. It's <= 1 if not ponder
+ double sd = 8.5;
- double move_importance(int ply) {
+ // Usage of increment follows quadratic distribution with the maximum at move 25
+ double inc = myInc * std::max(55.0, 120.0 - 0.12 * (moveNumber - 25) * (moveNumber - 25));
- const double XScale = 8.27;
- const double XShift = 59.;
- const double Skew = 0.179;
+ // 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)
+ {
+ ratio = (type == OptimumTime ? 1.0 : 6.0) / std::min(50, movesToGo);
- return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
- }
+ if (moveNumber <= 40)
+ ratio *= 1.1 - 0.001 * (moveNumber - 20) * (moveNumber - 20);
+ else
+ ratio *= 1.5;
+ }
+ // Otherwise we increase usage of remaining time as the game goes on
+ else
+ {
+ sd = 1 + 20 * moveNumber / (500.0 + moveNumber);
+ ratio = (type == OptimumTime ? 0.017 : 0.07) * sd;
+ }
- 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);
+ ratio = std::min(1.0, ratio * (1 + inc / (myTime * sd)));
+
+ assert(ratio <= 1);
- double moveImportance = (move_importance(ply) * slowMover) / 100;
- double otherMovesImportance = 0;
+ if (ponder && type == OptimumTime)
+ ratio *= 1.25;
- for (int i = 1; i < movesToGo; ++i)
- otherMovesImportance += move_importance(ply + 2 * i);
+ int time = int(ratio * (myTime - moveOverhead));
- double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance);
- double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance);
+ if (type == OptimumTime)
+ time -= 10; // Keep always at least 10 millisecs on the clock
- return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks an explicit cast
+ return std::max(0, time);
}
} // namespace
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"];
+ 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
- // real engine speed to avoid time losses.
+ // the real engine speed to avoid time losses.
if (npmsec)
{
if (!availableNodes) // Only once at game start
}
startTime = limits.startTime;
- unstablePvFactor = 1;
- optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime);
-
- const int MaxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
-
- // 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)
- {
- // 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 = std::max(hypMyTime, 0);
-
- int t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
- int t2 = minThinkingTime + remaining<MaxTime >(hypMyTime, hypMTG, ply, slowMover);
-
- optimumTime = std::min(t1, optimumTime);
- maximumTime = std::min(t2, maximumTime);
- }
-
- if (Options["Ponder"])
- optimumTime += optimumTime / 4;
+ optimumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
+ limits.movestogo, ply, ponder, OptimumTime);
+ maximumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
+ limits.movestogo, ply, ponder, MaxTime);
}
projects / stockfish / blobdiff