TimeManagement Time; // Our global time management object
-namespace {
-
- enum TimeType { OptimumTime, MaxTime };
-
- 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
-
-
- // 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.
-
- double move_importance(int ply) {
-
- constexpr double XScale = 6.85;
- constexpr double XShift = 64.5;
- constexpr double Skew = 0.171;
-
- return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
- }
-
- template<TimeType T>
- TimePoint remaining(TimePoint myTime, int movesToGo, int ply, TimePoint slowMover) {
-
- constexpr double TMaxRatio = (T == OptimumTime ? 1.0 : MaxRatio);
- constexpr double TStealRatio = (T == OptimumTime ? 0.0 : StealRatio);
-
- double moveImportance = (move_importance(ply) * slowMover) / 100.0;
- double otherMovesImportance = 0.0;
-
- for (int i = 1; i < movesToGo; ++i)
- otherMovesImportance += move_importance(ply + 2 * i);
-
- double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance);
- double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance);
-
- return TimePoint(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast
- }
-
-} // 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
+/// 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 = Options["Move Overhead"];
TimePoint slowMover = Options["Slow Mover"];
TimePoint npmsec = Options["nodestime"];
- TimePoint hypMyTime;
+
+ // 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.
}
startTime = limits.startTime;
- optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime);
- const int maxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
+ //Maximum move horizon of 50 moves
+ int mtg = limits.movestogo ? std::min(limits.movestogo, 50) : 50;
- // 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));
+ // Adjust moveOverhead if there are tiny increments
+ moveOverhead = std::max(10, std::min<int>(limits.inc[us] / 2, moveOverhead));
+
+ // 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));
- hypMyTime = std::max(hypMyTime, TimePoint(0));
+ // 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;
- TimePoint t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
- TimePoint t2 = minThinkingTime + remaining<MaxTime >(hypMyTime, hypMTG, ply, slowMover);
+ // 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(0.007 + std::pow(ply + 3.0, 0.5) / 250.0,
+ 0.2 * limits.time[us] / double(timeLeft));
+ max_scale = 4 + std::pow(ply + 3, 0.3);
+ }
- optimumTime = std::min(t1, optimumTime);
- maximumTime = std::min(t2, maximumTime);
+ // 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 = std::max<int>(minThinkingTime, opt_scale * timeLeft);
+ maximumTime = std::min(0.8 * limits.time[us] - moveOverhead, max_scale * optimumTime);
+
if (Options["Ponder"])
optimumTime += optimumTime / 4;
}
projects / stockfish / blobdiff