2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
5 Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
7 Stockfish is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Stockfish is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
27 TimeManagement Time; // Our global time management object
31 enum TimeType { OptimumTime, MaxTime };
33 int remaining(int myTime, int myInc, int moveOverhead, int movesToGo,
34 int moveNum, bool ponder, TimeType type) {
39 double ratio; // Which ratio of myTime we are going to use
41 // Usage of increment follows quadratic distribution with the maximum at move 25
42 double inc = myInc * std::max(55.0, 120 - 0.12 * (moveNum - 25) * (moveNum - 25));
44 // In moves-to-go we distribute time according to a quadratic function with
45 // the maximum around move 20 for 40 moves in y time case.
48 ratio = (type == OptimumTime ? 1.0 : 6.0) / std::min(50, movesToGo);
51 ratio *= 1.1 - 0.001 * (moveNum - 20) * (moveNum - 20);
55 ratio *= 1 + inc / (myTime * 8.5);
57 // Otherwise we increase usage of remaining time as the game goes on
60 double k = 1 + 20 * moveNum / (500.0 + moveNum);
61 ratio = (type == OptimumTime ? 0.017 : 0.07) * (k + inc / myTime);
64 int time = int(std::min(1.0, ratio) * std::max(0, myTime - moveOverhead));
66 if (type == OptimumTime && ponder)
75 /// init() is called at the beginning of the search and calculates the allowed
76 /// thinking time out of the time control and current game ply. We support four
77 /// different kinds of time controls, passed in 'limits':
79 /// inc == 0 && movestogo == 0 means: x basetime [sudden death!]
80 /// inc == 0 && movestogo != 0 means: x moves in y minutes
81 /// inc > 0 && movestogo == 0 means: x basetime + z increment
82 /// inc > 0 && movestogo != 0 means: x moves in y minutes + z increment
84 void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
86 int moveOverhead = Options["Move Overhead"];
87 int npmsec = Options["nodestime"];
88 bool ponder = Options["Ponder"];
90 // If we have to play in 'nodes as time' mode, then convert from time
91 // to nodes, and use resulting values in time management formulas.
92 // WARNING: Given npms (nodes per millisecond) must be much lower then
93 // the real engine speed to avoid time losses.
96 if (!availableNodes) // Only once at game start
97 availableNodes = npmsec * limits.time[us]; // Time is in msec
99 // Convert from millisecs to nodes
100 limits.time[us] = (int)availableNodes;
101 limits.inc[us] *= npmsec;
102 limits.npmsec = npmsec;
105 int moveNum = (ply + 1) / 2;
107 startTime = limits.startTime;
108 optimumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
109 limits.movestogo, moveNum, ponder, OptimumTime);
110 maximumTime = remaining(limits.time[us], limits.inc[us], moveOverhead,
111 limits.movestogo, moveNum, ponder, MaxTime);