Don't update pvHit after IID

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index b7e04fad2b22484ec2237e9d1f3ecdd81aece60a..cc8abc9ee814e48ccb1abca96d2e205921946ff9 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -227,10 +227,9 @@ void MainThread::search() {
   // Threads.stop. However, if we are pondering or in an infinite search,
   // the UCI protocol states that we shouldn't print the best move before the
   // GUI sends a "stop" or "ponderhit" command. We therefore simply wait here
-  // until the GUI sends one of those commands (which also raises Threads.stop).
-  Threads.stopOnPonderhit = true;
+  // until the GUI sends one of those commands.
 
-  while (!Threads.stop && (Threads.ponder || Limits.infinite))
+  while (!Threads.stop && (ponder || Limits.infinite))
   {} // Busy wait for a stop or a ponder reset
 
   // Stop the threads if not already stopped (also raise the stop if
@@ -448,7 +447,7 @@ void Thread::search() {
                   {
                       failedHighCnt = 0;
                       failedLow = true;
-                      Threads.stopOnPonderhit = false;
+                      mainThread->stopOnPonderhit = false;
                   }
               }
               else if (bestValue >= beta)
@@ -497,16 +496,13 @@ void Thread::search() {
       // Do we have time for the next iteration? Can we stop searching now?
       if (    Limits.use_time_management()
           && !Threads.stop
-          && !Threads.stopOnPonderhit)
+          && !mainThread->stopOnPonderhit)
       {
           double fallingEval = (306 + 119 * failedLow + 6 * (mainThread->previousScore - bestValue)) / 581.0;
           fallingEval        = std::max(0.5, std::min(1.5, fallingEval));
 
           // If the bestMove is stable over several iterations, reduce time accordingly
-          timeReduction = 1.0;
-          for (int i : {3, 4, 5})
-              if (lastBestMoveDepth * i < completedDepth)
-                  timeReduction *= 1.25;
+          timeReduction = lastBestMoveDepth + 10 * ONE_PLY < completedDepth ? 1.95 : 1.0;
 
           // Use part of the gained time from a previous stable move for the current move
           double bestMoveInstability = 1.0 + mainThread->bestMoveChanges;
@@ -518,8 +514,8 @@ void Thread::search() {
           {
               // If we are allowed to ponder do not stop the search now but
               // keep pondering until the GUI sends "ponderhit" or "stop".
-              if (Threads.ponder)
-                  Threads.stopOnPonderhit = true;
+              if (mainThread->ponder)
+                  mainThread->stopOnPonderhit = true;
               else
                   Threads.stop = true;
           }
@@ -578,7 +574,7 @@ namespace {
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue, pureStaticEval;
     bool ttHit, pvHit, inCheck, givesCheck, improving;
-    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact;
+    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture;
     Piece movedPiece;
     int moveCount, captureCount, quietCount;
 
@@ -643,7 +639,7 @@ namespace {
     ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
     ttMove =  rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0]
             : ttHit    ? tte->move() : MOVE_NONE;
-    pvHit = ttHit ? tte->pv_hit() : false;
+    pvHit = (ttHit && tte->pv_hit()) || (PvNode && depth > 4 * ONE_PLY);
 
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
@@ -677,11 +673,6 @@ namespace {
         return ttValue;
     }
 
-    if (   depth > 6 * ONE_PLY
-        && !excludedMove
-        && PvNode)
-        pvHit = true;
-
     // Step 5. Tablebases probe
     if (!rootNode && TB::Cardinality)
     {
@@ -881,7 +872,6 @@ namespace {
         tte = TT.probe(posKey, ttHit);
         ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
         ttMove = ttHit ? tte->move() : MOVE_NONE;
-        pvHit = ttHit ? tte->pv_hit() : false;
     }
 
 moves_loop: // When in check, search starts from here
@@ -898,7 +888,6 @@ moves_loop: // When in check, search starts from here
 
     skipQuiets = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
-    pvExact = PvNode && ttHit && tte->bound() == BOUND_EXACT;
 
     // Step 12. Loop through all pseudo-legal moves until no moves remain
     // or a beta cutoff occurs.
@@ -1043,7 +1032,7 @@ moves_loop: // When in check, search starts from here
           Depth r = reduction<PvNode>(improving, depth, moveCount);
 
           // Decrease reduction if position is or has been on the PV
-          if (pvHit && !PvNode)
+          if (pvHit)
               r -= ONE_PLY;
 
           // Decrease reduction if opponent's move count is high (~10 Elo)
@@ -1052,10 +1041,6 @@ moves_loop: // When in check, search starts from here
 
           if (!captureOrPromotion)
           {
-              // Decrease reduction for exact PV nodes (~0 Elo)
-              if (pvExact)
-                  r -= ONE_PLY;
-
               // Increase reduction if ttMove is a capture (~0 Elo)
               if (ttCapture)
                   r += ONE_PLY;
@@ -1292,7 +1277,7 @@ moves_loop: // When in check, search starts from here
     tte = TT.probe(posKey, ttHit);
     ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
     ttMove = ttHit ? tte->move() : MOVE_NONE;
-    pvHit = ttHit ? tte->pv_hit() : false;
+    pvHit = ttHit && tte->pv_hit();
 
     if (  !PvNode
         && ttHit
@@ -1608,10 +1593,10 @@ void MainThread::check_time() {
   }
 
   // We should not stop pondering until told so by the GUI
-  if (Threads.ponder)
+  if (ponder)
       return;
 
-  if (   (Limits.use_time_management() && elapsed > Time.maximum() - 10)
+  if (   (Limits.use_time_management() && (elapsed > Time.maximum() - 10 || stopOnPonderhit))
       || (Limits.movetime && elapsed >= Limits.movetime)
       || (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes))
       Threads.stop = true;