/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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 <cmath>
#include "search.h"
#include "timeman.h"
-#include "ucioption.h"
+#include "uci.h"
-namespace {
-
- /// Constants
-
- 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) {
+TimeManagement Time; // Our global time management object
- return 1 / pow((1 + exp((ply - xshift) / xscale)), skewfactor) + 1e-3; // Ensure non-zero
- }
-
-
- /// Function Prototypes
+namespace {
enum TimeType { OptimumTime, MaxTime };
- template<TimeType>
- int remaining(int myTime, int movesToGo, int fullMoveNumber, int slowMover);
-}
+ int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
+ int ply, bool ponder, TimeType type) {
+ if (myTime <= 0)
+ return 0;
-void TimeManager::pv_instability(double bestMoveChanges) {
+ 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;
- unstablePVExtraTime = int(bestMoveChanges * optimumSearchTime / 1.4);
-}
+ // 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));
+ // 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);
-void TimeManager::init(const Search::LimitsType& limits, int currentPly, Color us)
-{
- /* We support four different kind of time controls:
+ 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;
+ }
- 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
+ ratio = std::min(1.0, ratio * (1 + inc / (myTime * sd)));
- Time management is adjusted by following UCI parameters:
+ assert(ratio <= 1);
- 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
- */
+ if (ponder && type == OptimumTime)
+ ratio *= 1.25;
- int hypMTG, hypMyTime, t1, t2;
+ int time = int(ratio * (myTime - moveOverhead));
- // 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"];
+ if (type == OptimumTime)
+ time -= 10; // Keep always at least 10 millisecs on the clock
- // Initialize all to maximum values but unstablePVExtraTime that is reset
- unstablePVExtraTime = 0;
- optimumSearchTime = maximumSearchTime = limits.time[us];
-
- // 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);
+ return std::max(0, time);
}
- if (Options["Ponder"])
- optimumSearchTime += optimumSearchTime / 4;
+} // namespace
- // Make sure that maxSearchTime is not over absoluteMaxSearchTime
- optimumSearchTime = std::min(optimumSearchTime, maximumSearchTime);
-}
+/// 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
-namespace {
-
- template<TimeType T>
- int remaining(int myTime, int movesToGo, int currentPly, int slowMover)
+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)
{
- const double TMaxRatio = (T == OptimumTime ? 1 : MaxRatio);
- const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
-
- double thisMoveImportance = (move_importance(currentPly) * slowMover) / 100;
- double otherMovesImportance = 0;
+ if (!availableNodes) // Only once at game start
+ availableNodes = npmsec * limits.time[us]; // Time is in msec
- 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)));
+ // Convert from millisecs to nodes
+ limits.time[us] = (int)availableNodes;
+ limits.inc[us] *= npmsec;
+ limits.npmsec = npmsec;
}
+
+ startTime = limits.startTime;
+ 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