X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftimeman.cpp;h=484aaa65998684cf6e6718d5c06d8d3b3a4052fd;hp=b5d1a66c30b05faf1d26da029ebd42ab7bbdfe8a;hb=cff9a8672c1da7d36bc54d168d10ea2b1ce5c728;hpb=daf0fe1f57337d33f9e0af5a8aa8ef0868b20417 diff --git a/src/timeman.cpp b/src/timeman.cpp index b5d1a66c..484aaa65 100644 --- a/src/timeman.cpp +++ b/src/timeman.cpp @@ -2,7 +2,7 @@ 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) 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 @@ -19,6 +19,8 @@ */ #include +#include +#include #include "search.h" #include "timeman.h" @@ -30,50 +32,41 @@ namespace { enum TimeType { OptimumTime, MaxTime }; - int remaining(int myTime, int myInc, int moveOverhead, int movesToGo, - int ply, bool ponder, TimeType type) { + 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 - if (myTime <= 0) - return 0; - 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; + // 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 the CCRL game database with some simple filtering criteria. - // 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)); + double move_importance(int ply) { - // 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); + constexpr double XScale = 6.85; + constexpr double XShift = 64.5; + constexpr double Skew = 0.171; - 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; - } + return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero + } - ratio = std::min(1.0, ratio * (1 + inc / (myTime * sd))); + template + TimePoint remaining(TimePoint myTime, int movesToGo, int ply, TimePoint slowMover) { - assert(ratio <= 1); + constexpr double TMaxRatio = (T == OptimumTime ? 1.0 : MaxRatio); + constexpr double TStealRatio = (T == OptimumTime ? 0.0 : StealRatio); - if (ponder && type == OptimumTime) - ratio *= 1.25; + double moveImportance = (move_importance(ply) * slowMover) / 100.0; + double otherMovesImportance = 0.0; - int time = int(ratio * (myTime - moveOverhead)); + for (int i = 1; i < movesToGo; ++i) + otherMovesImportance += move_importance(ply + 2 * i); - if (type == OptimumTime) - time -= 10; // Keep always at least 10 millisecs on the clock + double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance); + double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance); - return std::max(0, time); + return TimePoint(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast } } // namespace @@ -88,30 +81,53 @@ 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 moveOverhead = Options["Move Overhead"]; - int npmsec = Options["nodestime"]; - bool ponder = Options["Ponder"]; +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 - // the 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; - 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); + 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 + hypMyTime = limits.time[us] + + limits.inc[us] * (hypMTG - 1) + - moveOverhead * (2 + std::min(hypMTG, 40)); + + hypMyTime = std::max(hypMyTime, TimePoint(0)); + + TimePoint t1 = minThinkingTime + remaining(hypMyTime, hypMTG, ply, slowMover); + TimePoint t2 = minThinkingTime + remaining(hypMyTime, hypMTG, ply, slowMover); + + optimumTime = std::min(t1, optimumTime); + maximumTime = std::min(t2, maximumTime); + } + + if (Options["Ponder"]) + optimumTime += optimumTime / 4; }