Minimal thinking time, even if only one rootMove.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 7f29f771c0a9eb3e05f8881502182c822e0f1e0f..35110538170c5cb03732a955b1cbe4b616eb7dc2 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -272,9 +272,9 @@ void MainThread::search() {
   Thread* bestThread = this;
 
   // Check if there are threads with a better score than main thread
-  if (    Options["MultiPV"] == 1
+  if (    int(Options["MultiPV"]) == 1
       && !Limits.depth
-      && !(Skill(Options["Skill Level"]).enabled() || Options["UCI_LimitStrength"])
+      && !(Skill(Options["Skill Level"]).enabled() || int(Options["UCI_LimitStrength"]))
       &&  rootMoves[0].pv[0] != MOVE_NONE)
   {
       std::map<Move, int64_t> votes;
@@ -350,14 +350,17 @@ void Thread::search() {
   if (mainThread)
   {
       if (mainThread->bestPreviousScore == VALUE_INFINITE)
-          for (int i=0; i<4; ++i)
+          for (int i = 0; i < 4; ++i)
               mainThread->iterValue[i] = VALUE_ZERO;
       else
-          for (int i=0; i<4; ++i)
+          for (int i = 0; i < 4; ++i)
               mainThread->iterValue[i] = mainThread->bestPreviousScore;
   }
 
-  size_t multiPV = Options["MultiPV"];
+  std::copy(&lowPlyHistory[2][0], &lowPlyHistory.back().back() + 1, &lowPlyHistory[0][0]);
+  std::fill(&lowPlyHistory[MAX_LPH - 2][0], &lowPlyHistory.back().back() + 1, 0);
+
+  size_t multiPV = size_t(Options["MultiPV"]);
 
   // Pick integer skill levels, but non-deterministically round up or down
   // such that the average integer skill corresponds to the input floating point one.
@@ -537,8 +540,8 @@ void Thread::search() {
           && !Threads.stop
           && !mainThread->stopOnPonderhit)
       {
-          double fallingEval = (332 +  6 * (mainThread->bestPreviousScore - bestValue)
-                                    +  6 * (mainThread->iterValue[iterIdx]  - bestValue)) / 704.0;
+          double fallingEval = (332 + 6 * (mainThread->bestPreviousScore - bestValue)
+                                    + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 704.0;
           fallingEval = Utility::clamp(fallingEval, 0.5, 1.5);
 
           // If the bestMove is stable over several iterations, reduce time accordingly
@@ -553,9 +556,11 @@ void Thread::search() {
           }
           double bestMoveInstability = 1 + totBestMoveChanges / Threads.size();
 
-          // Stop the search if we have only one legal move, or if available time elapsed
-          if (   rootMoves.size() == 1
-              || Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability)
+          double totalTime = rootMoves.size() == 1 ? 0 :
+                             Time.optimum() * fallingEval * reduction * bestMoveInstability;
+
+          // Stop the search if we have exceeded the totalTime, at least 1ms search.
+          if (Time.elapsed() > totalTime)
           {
               // If we are allowed to ponder do not stop the search now but
               // keep pondering until the GUI sends "ponderhit" or "stop".
@@ -566,7 +571,7 @@ void Thread::search() {
           }
           else if (   Threads.increaseDepth
                    && !mainThread->ponder
-                   && Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability * 0.6)
+                   && Time.elapsed() > totalTime * 0.6)
                    Threads.increaseDepth = false;
           else
                    Threads.increaseDepth = true;
@@ -627,7 +632,8 @@ namespace {
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue;
     bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture;
-    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR;
+    bool captureOrPromotion, doFullDepthSearch, moveCountPruning,
+         ttCapture, singularQuietLMR;
     Piece movedPiece;
     int moveCount, captureCount, quietCount;
 
@@ -968,7 +974,7 @@ moves_loop: // When in check, search starts from here
                                       depth > 12 ? ss->ply : MAX_PLY);
 
     value = bestValue;
-    singularLMR = moveCountPruning = false;
+    singularQuietLMR = moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
     // Mark this node as being searched
@@ -1052,6 +1058,7 @@ moves_loop: // When in check, search starts from here
               // Futility pruning for captures
               if (   !givesCheck
                   && lmrDepth < 6
+                  && !(PvNode && abs(bestValue) < 2)
                   && !ss->inCheck
                   && ss->staticEval + 270 + 384 * lmrDepth + PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] <= alpha)
                   continue;
@@ -1088,7 +1095,7 @@ moves_loop: // When in check, search starts from here
           if (value < singularBeta)
           {
               extension = 1;
-              singularLMR = true;
+              singularQuietLMR = !ttCapture;
           }
 
           // Multi-cut pruning
@@ -1194,7 +1201,7 @@ moves_loop: // When in check, search starts from here
               r--;
 
           // Decrease reduction if ttMove has been singularly extended (~3 Elo)
-          if (singularLMR)
+          if (singularQuietLMR)
               r -= 1 + formerPv;
 
           if (!captureOrPromotion)