Increase reduction if tt-move is a capture

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 51d3ae8cba3910b48301adab0507316e09acb850..12cbffe020b25f7bf92921dc860e23e83eb3d919 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -85,7 +85,7 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth depth) {
-    int d = depth / ONE_PLY ;
+    int d = depth / ONE_PLY;
     return d > 17 ? 0 : d * d + 2 * d - 2;
   }
 
@@ -361,7 +361,7 @@ void Thread::search() {
   multiPV = std::min(multiPV, rootMoves.size());
 
   // Iterative deepening loop until requested to stop or the target depth is reached
-  while (   (rootDepth += ONE_PLY) < DEPTH_MAX
+  while (   (rootDepth = rootDepth + ONE_PLY) < DEPTH_MAX
          && !Signals.stop
          && (!Limits.depth || Threads.main()->rootDepth / ONE_PLY <= Limits.depth))
   {
@@ -400,6 +400,9 @@ void Thread::search() {
           {
               bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false, false);
 
+              this->tbHits = rootPos.tb_hits();
+              this->nodes = rootPos.nodes_searched();
+
               // Bring the best move to the front. It is critical that sorting
               // is done with a stable algorithm because all the values but the
               // first and eventually the new best one are set to -VALUE_INFINITE
@@ -551,7 +554,7 @@ namespace {
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval;
     bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
-    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets;
+    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture;
     Piece moved_piece;
     int moveCount, quietCount;
 
@@ -568,6 +571,9 @@ namespace {
     {
         thisThread->resetCalls = false;
 
+        thisThread->tbHits = pos.tb_hits();
+        thisThread->nodes = pos.nodes_searched();
+
         // At low node count increase the checking rate to about 0.1% of nodes
         // otherwise use a default value.
         thisThread->callsCnt = Limits.nodes ? std::min(4096, int(Limits.nodes / 1024))
@@ -668,7 +674,7 @@ namespace {
 
             if (err != TB::ProbeState::FAIL)
             {
-                thisThread->tbHits++;
+                pos.increment_tbHits();
 
                 int drawScore = TB::UseRule50 ? 1 : 0;
 
@@ -836,6 +842,7 @@ moves_loop: // When in check search starts from here
                            && (tte->bound() & BOUND_LOWER)
                            &&  tte->depth() >= depth - 3 * ONE_PLY;
     skipQuiets = false;
+    ttCapture = false;
 
     // Step 11. Loop through moves
     // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
@@ -953,6 +960,9 @@ moves_loop: // When in check search starts from here
           ss->moveCount = --moveCount;
           continue;
       }
+      
+      if (move == ttMove && captureOrPromotion)
+          ttCapture = true;
 
       // Update the current move (this must be done after singular extension search)
       ss->currentMove = move;
@@ -973,6 +983,11 @@ moves_loop: // When in check search starts from here
               r -= r ? ONE_PLY : DEPTH_ZERO;
           else
           {
+          
+              // Increase reduction if ttMove is a capture
+              if (ttCapture)
+                  r += ONE_PLY;
+          
               // Increase reduction for cut nodes
               if (cutNode)
                   r += 2 * ONE_PLY;
@@ -1473,7 +1488,7 @@ moves_loop: // When in check search starts from here
 
   void check_time() {
 
-    static TimePoint lastInfoTime = now();
+    static std::atomic<TimePoint> lastInfoTime = { now() };
 
     int elapsed = Time.elapsed();
     TimePoint tick = Limits.startTime + elapsed;