Simplify time management and fix 'ponder on' bug

Simplify time management code by removing hard stops for unchanging first root moves.
Search is now stopped earlier at the end iteration if it did not have fail-lows at root.

This simplification also fixes pondering bug. Ponder flag was true by default
and cutechess-cli doesn't change it to false even though no pondering is possible.
Fix the issue by setting the default value of 'Ponder' flag to false.

10+0.1:
ELO: 3.51 +-3.0 (95%) LOS: 99.0%
Total: 20000 W: 3898 L: 3696 D: 12406

40+0.4:
ELO: 1.39 +-2.7 (95%) LOS: 84.7%
Total: 20000 W: 3104 L: 3024 D: 13872

60+0.06:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37231 W: 5333 L: 5236 D: 26662

Stopped run at 100+1:
LLR: 1.09 (-2.94,2.94) [-3.00,1.00]
Total: 37253 W: 4862 L: 4856 D: 27535

Resolves #523
Fixes #510

diff --git a/src/search.cpp b/src/search.cpp
index 3c34f185c35eda640b5022851eccdf65631a588a..e5c485fce59d368dc5fb227dd3851084baa0da37 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -127,6 +127,7 @@ namespace {
   };
 
   EasyMoveManager EasyMove;
   };
 
   EasyMoveManager EasyMove;

+  bool easyPlayed, failedLow;

   double BestMoveChanges;
   Value DrawValue[COLOR_NB];
   CounterMovesHistoryStats CounterMovesHistory;
   double BestMoveChanges;
   Value DrawValue[COLOR_NB];
   CounterMovesHistoryStats CounterMovesHistory;


@@ -368,6 +369,7 @@ void Thread::search() {
   {
       easyMove = EasyMove.get(rootPos.key());
       EasyMove.clear();
   {
       easyMove = EasyMove.get(rootPos.key());
       EasyMove.clear();

+      easyPlayed = false;

       BestMoveChanges = 0;
       TT.new_search();
   }
       BestMoveChanges = 0;
       TT.new_search();
   }


@@ -391,7 +393,7 @@ void Thread::search() {
 
       // Age out PV variability metric
       if (isMainThread)
 
       // Age out PV variability metric
       if (isMainThread)

-          BestMoveChanges *= 0.5;
+          BestMoveChanges *= 0.505, failedLow = false;

 
       // Save the last iteration's scores before first PV line is searched and
       // all the move scores except the (new) PV are set to -VALUE_INFINITE.
 
       // Save the last iteration's scores before first PV line is searched and
       // all the move scores except the (new) PV are set to -VALUE_INFINITE.


@@ -452,7 +454,7 @@ void Thread::search() {
 
                   if (isMainThread)
                   {
 
                   if (isMainThread)
                   {

-                      Signals.failedLowAtRoot = true;
+                      failedLow = true;

                       Signals.stopOnPonderhit = false;
                   }
               }
                       Signals.stopOnPonderhit = false;
                   }
               }


@@ -512,10 +514,10 @@ void Thread::search() {
               // of the available time has been used or we matched an easyMove
               // from the previous search and just did a fast verification.
               if (   rootMoves.size() == 1
               // of the available time has been used or we matched an easyMove
               // from the previous search and just did a fast verification.
               if (   rootMoves.size() == 1

-                  || Time.elapsed() > Time.available()
-                  || (   rootMoves[0].pv[0] == easyMove
+                  || Time.elapsed() > Time.available() * (failedLow? 641 : 315)/640
+                 || ( easyPlayed = (   rootMoves[0].pv[0] == easyMove

                       && BestMoveChanges < 0.03
                       && BestMoveChanges < 0.03

-                      && Time.elapsed() > Time.available() / 10))
+                      && Time.elapsed() > Time.available() / 8)))

               {
                   // If we are allowed to ponder do not stop the search now but
                   // keep pondering until the GUI sends "ponderhit" or "stop".
               {
                   // If we are allowed to ponder do not stop the search now but
                   // keep pondering until the GUI sends "ponderhit" or "stop".


@@ -538,7 +540,7 @@ void Thread::search() {
 
   // Clear any candidate easy move that wasn't stable for the last search
   // iterations; the second condition prevents consecutive fast moves.
 
   // Clear any candidate easy move that wasn't stable for the last search
   // iterations; the second condition prevents consecutive fast moves.

-  if (EasyMove.stableCnt < 6 || Time.elapsed() < Time.available())
+  if (EasyMove.stableCnt < 6 || easyPlayed)

       EasyMove.clear();
 
   // If skill level is enabled, swap best PV line with the sub-optimal one
       EasyMove.clear();
 
   // If skill level is enabled, swap best PV line with the sub-optimal one


@@ -859,15 +861,10 @@ moves_loop: // When in check search starts from here
 
       ss->moveCount = ++moveCount;
 
 
       ss->moveCount = ++moveCount;
 

-      if (RootNode && thisThread == Threads.main())
-      {
-          Signals.firstRootMove = (moveCount == 1);
-
-          if (Time.elapsed() > 3000)
-              sync_cout << "info depth " << depth / ONE_PLY
-                        << " currmove " << UCI::move(move, pos.is_chess960())
-                        << " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl;
-      }
+      if (RootNode && thisThread == Threads.main() && Time.elapsed() > 3000)
+          sync_cout << "info depth " << depth / ONE_PLY
+                    << " currmove " << UCI::move(move, pos.is_chess960())
+                    << " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl;

 
       if (PvNode)
           (ss+1)->pv = nullptr;
 
       if (PvNode)
           (ss+1)->pv = nullptr;


@@ -1486,19 +1483,9 @@ moves_loop: // When in check search starts from here
     if (Limits.ponder)
         return;
 
     if (Limits.ponder)
         return;
 

-    if (Limits.use_time_management())
-    {
-        bool stillAtFirstMove =    Signals.firstRootMove.load(std::memory_order_relaxed)
-                               && !Signals.failedLowAtRoot.load(std::memory_order_relaxed)
-                               &&  elapsed > Time.available() * 3 / 4;
-
-        if (stillAtFirstMove || elapsed > Time.maximum() - 10)
-            Signals.stop = true;
-    }
-    else if (Limits.movetime && elapsed >= Limits.movetime)
-        Signals.stop = true;
-
-    else if (Limits.nodes && Threads.nodes_searched() >= Limits.nodes)
+    if (   (Limits.use_time_management() && elapsed > Time.maximum() - 10)
+        || (Limits.movetime && elapsed >= Limits.movetime)
+        || (Limits.nodes && Threads.nodes_searched() >= Limits.nodes))

             Signals.stop = true;
   }
 
             Signals.stop = true;
   }
 

diff --git a/src/search.h b/src/search.h
index d755f1c2e873cf907d4c13d7af6812065f9c7714..2a9a37370af7b713bc730ece27ed47ae1de066c7 100644 (file)
--- a/src/search.h
+++ b/src/search.h
@@ -93,7 +93,7 @@ struct LimitsType {
 /// typically in an async fashion e.g. to stop the search by the GUI.
 
 struct SignalsType {
 /// typically in an async fashion e.g. to stop the search by the GUI.
 
 struct SignalsType {

-  std::atomic_bool stop, stopOnPonderhit, firstRootMove, failedLowAtRoot;
+  std::atomic_bool stop, stopOnPonderhit;

 };
 
 typedef std::unique_ptr<std::stack<StateInfo>> StateStackPtr;
 };
 
 typedef std::unique_ptr<std::stack<StateInfo>> StateStackPtr;

diff --git a/src/thread.cpp b/src/thread.cpp
index c5c8bb0d90011f093cd578854a7878002799851c..3b6074acf0f84a0e5b397254afc0da14535f6068 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -174,8 +174,7 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
 
   main()->wait_for_search_finished();
 
 
   main()->wait_for_search_finished();
 

-  Signals.stopOnPonderhit = Signals.firstRootMove = false;
-  Signals.stop = Signals.failedLowAtRoot = false;
+  Signals.stopOnPonderhit = Signals.stop = false;

 
   main()->rootMoves.clear();
   main()->rootPos = pos;
 
   main()->rootMoves.clear();
   main()->rootPos = pos;

diff --git a/src/timeman.cpp b/src/timeman.cpp
index 3a4e157f8b145f1ba43de49b58c7b6db4093f643..47f57ab3b8d290642ef1f34b47f75a5ecdf91d68 100644 (file)
--- a/src/timeman.cpp
+++ b/src/timeman.cpp
@@ -32,8 +32,8 @@ namespace {
   enum TimeType { OptimumTime, MaxTime };
 
   const int MoveHorizon   = 50;   // Plan time management at most this many moves ahead
   enum TimeType { OptimumTime, MaxTime };
 
   const int MoveHorizon   = 50;   // Plan time management at most this many moves ahead

-  const double MaxRatio   = 7.0;  // When in trouble, we can step over reserved time with this ratio
-  const double StealRatio = 0.33; // However we must not steal time from remaining moves over this ratio
+  const double MaxRatio   = 6.93;  // When in trouble, we can step over reserved time with this ratio
+  const double StealRatio = 0.36; // However we must not steal time from remaining moves over this ratio

 
 
   // move_importance() is a skew-logistic function based on naive statistical
 
 
   // move_importance() is a skew-logistic function based on naive statistical


@@ -43,9 +43,9 @@ namespace {
 
   double move_importance(int ply) {
 
 
   double move_importance(int ply) {
 

-    const double XScale = 9.3;
-    const double XShift = 59.8;
-    const double Skew   = 0.172;
+    const double XScale = 8.27;
+    const double XShift = 59.;
+    const double Skew   = 0.179;

 
     return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
   }
 
     return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
   }


@@ -129,6 +129,4 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
 
   if (Options["Ponder"])
       optimumTime += optimumTime / 4;
 
   if (Options["Ponder"])
       optimumTime += optimumTime / 4;

-
-  optimumTime = std::min(optimumTime, maximumTime);

 }
 }

diff --git a/src/timeman.h b/src/timeman.h
index b6eb3485c8dfd04b190daadbdb7bc17d7e50b1c4..3faba00d292498f0b1875b40d6051b455084a9c0 100644 (file)
--- a/src/timeman.h
+++ b/src/timeman.h
@@ -31,7 +31,7 @@ class TimeManagement {
 public:
   void init(Search::LimitsType& limits, Color us, int ply);
   void pv_instability(double bestMoveChanges) { unstablePvFactor = 1 + bestMoveChanges; }
 public:
   void init(Search::LimitsType& limits, Color us, int ply);
   void pv_instability(double bestMoveChanges) { unstablePvFactor = 1 + bestMoveChanges; }

-  int available() const { return int(optimumTime * unstablePvFactor * 0.76); }
+  int available() const { return int(optimumTime * unstablePvFactor * 1.016); }

   int maximum() const { return maximumTime; }
   int elapsed() const { return int(Search::Limits.npmsec ? Threads.nodes_searched() : now() - startTime); }
 
   int maximum() const { return maximumTime; }
   int elapsed() const { return int(Search::Limits.npmsec ? Threads.nodes_searched() : now() - startTime); }
 

diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index f493e8401aa5f323d9328bfb93e70a1e9b52aa52..23af481b28c474f3cc31e953adba924cc015e79c 100644 (file)
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -61,12 +61,12 @@ void init(OptionsMap& o) {
   o["Threads"]               << Option(1, 1, 128, on_threads);
   o["Hash"]                  << Option(16, 1, MaxHashMB, on_hash_size);
   o["Clear Hash"]            << Option(on_clear_hash);
   o["Threads"]               << Option(1, 1, 128, on_threads);
   o["Hash"]                  << Option(16, 1, MaxHashMB, on_hash_size);
   o["Clear Hash"]            << Option(on_clear_hash);

-  o["Ponder"]                << Option(true);
+  o["Ponder"]                << Option(false);

   o["MultiPV"]               << Option(1, 1, 500);
   o["Skill Level"]           << Option(20, 0, 20);
   o["Move Overhead"]         << Option(30, 0, 5000);
   o["Minimum Thinking Time"] << Option(20, 0, 5000);
   o["MultiPV"]               << Option(1, 1, 500);
   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(80, 10, 1000);
+  o["Slow Mover"]            << Option(84, 10, 1000);

   o["nodestime"]             << Option(0, 0, 10000);
   o["UCI_Chess960"]          << Option(false);
   o["SyzygyPath"]            << Option("<empty>", on_tb_path);
   o["nodestime"]             << Option(0, 0, 10000);
   o["UCI_Chess960"]          << Option(false);
   o["SyzygyPath"]            << Option("<empty>", on_tb_path);