/*
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) 2004-2020 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
*/
#include <algorithm>
+#include <cfloat>
+#include <cmath>
#include "search.h"
#include "timeman.h"
TimeManagement Time; // Our global time management object
-namespace {
- enum TimeType { OptimumTime, MaxTime };
+/// TimeManagement::init() is 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)
- int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
- int ply, bool ponder, TimeType type) {
+void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
- if (myTime <= 0)
- return 0;
+ TimePoint moveOverhead = TimePoint(Options["Move Overhead"]);
+ TimePoint slowMover = TimePoint(Options["Slow Mover"]);
+ TimePoint npmsec = TimePoint(Options["nodestime"]);
- 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;
-
- // 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);
-
- 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;
- }
-
- ratio = std::min(1.0, ratio * (1 + inc / (myTime * sd)));
-
- assert(ratio <= 1);
-
- if (ponder && type == OptimumTime)
- ratio *= 1.25;
-
- int time = int(ratio * (myTime - moveOverhead));
-
- if (type == OptimumTime)
- time -= 10; // Keep always at least 10 millisecs on the clock
-
- return std::max(0, time);
- }
-
-} // namespace
-
-
-/// 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
-
-void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
-{
- int moveOverhead = Options["Move Overhead"];
- int npmsec = Options["nodestime"];
- bool ponder = Options["Ponder"];
+ // 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: 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);
+
+ // Maximum move horizon of 50 moves
+ int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
+
+ // 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));
+
+ // A user may scale time usage by setting UCI option "Slow Mover"
+ // Default is 100 and changing this value will probably lose elo.
+ timeLeft = slowMover * timeLeft / 100;
+
+ // x basetime (+ z increment)
+ // If there is a healthy increment, timeLeft can exceed actual available
+ // game time for the current move, so also cap to 20% of available game time.
+ if (limits.movestogo == 0)
+ {
+ optScale = std::min(0.0084 + std::pow(ply + 3.0, 0.5) * 0.0042,
+ 0.2 * limits.time[us] / double(timeLeft));
+ maxScale = std::min(7.0, 4.0 + ply / 12.0);
+ }
+
+ // x moves in y seconds (+ z increment)
+ else
+ {
+ optScale = std::min((0.8 + ply / 128.0) / mtg,
+ 0.8 * limits.time[us] / double(timeLeft));
+ maxScale = std::min(6.3, 1.5 + 0.11 * mtg);
+ }
+
+ // Never use more than 80% of the available time for this move
+ optimumTime = TimePoint(optScale * timeLeft);
+ maximumTime = TimePoint(std::min(0.8 * limits.time[us] - moveOverhead, maxScale * optimumTime));
+
+ if (Options["Ponder"])
+ optimumTime += optimumTime / 4;
}
projects / stockfish / blobdiff