From: Leonid Pechenik <lp@home>
Date: Mon, 22 Feb 2016 17:03:33 +0000 (-0500)
Subject: Revert "Remove slowMover"
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=d5ba8e827d840995e79435986a8a7a2a45626eca;ds=sidebyside

Revert "Remove slowMover"

This reverts commit 77fa960f8923ca83ba0391835d50f4230ac6a345.

Resolves #590
---

diff --git a/src/timeman.cpp b/src/timeman.cpp
index e9f1ffe5..bc9c2e5b 100644
--- a/src/timeman.cpp
+++ b/src/timeman.cpp
@@ -37,25 +37,27 @@ namespace {
   const double StealRatio = 0.35; // However we must not steal time from remaining moves over this ratio
 
 
-  // move_importance() is an exponential function based on naive observation
-  // that a game is closer to be decided after each half-move. This function
-  // should be decreasing and with "nice" convexity properties.
+  // 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) {
 
-    const double PlyScale = 109.3265;
-    const double PlyGrowth = 4.0;
+    const double XScale = 7.64;
+    const double XShift = 58.4;
+    const double Skew   = 0.183;
 
-    return exp(-pow(ply / PlyScale, PlyGrowth)) + DBL_MIN; // Ensure non-zero
+    return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
   }
 
   template<TimeType T>
-  int remaining(int myTime, int movesToGo, int ply)
+  int remaining(int myTime, int movesToGo, int ply, int slowMover)
   {
     const double TMaxRatio   = (T == OptimumTime ? 1 : MaxRatio);
     const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
 
-    double moveImportance = move_importance(ply);
+    double moveImportance = (move_importance(ply) * slowMover) / 100;
     double otherMovesImportance = 0;
 
     for (int i = 1; i < movesToGo; ++i)
@@ -83,6 +85,7 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
 {
   int minThinkingTime = Options["Minimum Thinking Time"];
   int moveOverhead    = Options["Move Overhead"];
+  int slowMover       = Options["Slow Mover"];
   int npmsec          = Options["nodestime"];
 
   // If we have to play in 'nodes as time' mode, then convert from time
@@ -117,8 +120,8 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
 
       hypMyTime = std::max(hypMyTime, 0);
 
-      int t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply);
-      int t2 = minThinkingTime + remaining<MaxTime    >(hypMyTime, hypMTG, ply);
+      int t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
+      int t2 = minThinkingTime + remaining<MaxTime    >(hypMyTime, hypMTG, ply, slowMover);
 
       optimumTime = std::min(t1, optimumTime);
       maximumTime = std::min(t2, maximumTime);
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 35ff6559..243f11e3 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -67,6 +67,7 @@ void init(OptionsMap& o) {
   o["Skill Level"]           << Option(20, 0, 20);
   o["Move Overhead"]         << Option(30, 0, 5000);
   o["Minimum Thinking Time"] << Option(20, 0, 5000);
+  o["Slow Mover"]            << Option(89, 10, 1000);
   o["nodestime"]             << Option(0, 0, 10000);
   o["UCI_Chess960"]          << Option(false);
   o["SyzygyPath"]            << Option("<empty>", on_tb_path);