/*
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) 2015-2020 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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#include
#include
#include
#include "search.h"
#include "timeman.h"
#include "uci.h"
TimeManagement Time; // Our global time management object
/// 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)
void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
TimePoint moveOverhead = TimePoint(Options["Move Overhead"]);
TimePoint slowMover = TimePoint(Options["Slow Mover"]);
TimePoint npmsec = TimePoint(Options["nodestime"]);
// opt_scale is a percentage of available time to use for the current move.
// max_scale is a multiplier applied to optimumTime.
double opt_scale, max_scale;
// 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: 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 milliseconds to nodes
limits.time[us] = TimePoint(availableNodes);
limits.inc[us] *= npmsec;
limits.npmsec = npmsec;
}
startTime = limits.startTime;
// 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)
{
opt_scale = std::min(0.008 + std::pow(ply + 3.0, 0.5) / 250.0,
0.2 * limits.time[us] / double(timeLeft));
max_scale = std::min(7.0, 4.0 + ply / 12.0);
}
// x moves in y seconds (+ z increment)
else
{
opt_scale = std::min((0.8 + ply / 128.0) / mtg,
0.8 * limits.time[us] / double(timeLeft));
max_scale = std::min(6.3, 1.5 + 0.11 * mtg);
}
// Never use more than 80% of the available time for this move
optimumTime = TimePoint(opt_scale * timeLeft);
maximumTime = TimePoint(std::min(0.8 * limits.time[us] - moveOverhead, max_scale * optimumTime));
if (Options["Ponder"])
optimumTime += optimumTime / 4;
}