Simplify ttHitAverage away

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 73fc8a55fef18d57212ff4bf0deaf7a87ffa846f..bdd139cec4d7020c52fb5529e231bf5f1ecc300e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -332,7 +332,6 @@ void Thread::search() {
 
   multiPV = std::min(multiPV, rootMoves.size());
 
-  ttHitAverage.set(50, 100);                  // initialize the running average at 50%
   doubleExtensionAverage[WHITE].set(0, 100);  // initialize the running average at 0%
   doubleExtensionAverage[BLACK].set(0, 100);  // initialize the running average at 0%
 
@@ -670,9 +669,6 @@ namespace {
         && is_ok((ss-1)->currentMove))
         thisThread->lowPlyHistory[ss->ply - 1][from_to((ss-1)->currentMove)] << stat_bonus(depth - 5);
 
-    // running average of ttHit
-    thisThread->ttHitAverage.update(ss->ttHit);
-
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
         && ss->ttHit
@@ -1123,18 +1119,9 @@ moves_loop: // When in check, search starts here
           else if (singularBeta >= beta)
               return singularBeta;
 
-          // If the eval of ttMove is greater than beta we try also if there is another
-          // move that pushes it over beta, if so the position also has probably multiple
-          // moves giving fail highs. We will then reduce the ttMove (negative extension).
+          // If the eval of ttMove is greater than beta, we reduce it (negative extension)
           else if (ttValue >= beta)
-          {
-              ss->excludedMove = move;
-              value = search<NonPV>(pos, ss, beta - 1, beta, (depth + 3) / 2, cutNode);
-              ss->excludedMove = MOVE_NONE;
-
-              if (value >= beta)
-                  extension = -2;
-          }
+              extension = -2;
       }
 
       // Capture extensions for PvNodes and cutNodes
@@ -1191,10 +1178,6 @@ moves_loop: // When in check, search starts here
               && bestMoveCount <= 3)
               r--;
 
-          // Decrease reduction if the ttHit running average is large (~0 Elo)
-          if (thisThread->ttHitAverage.is_greater(537, 1024))
-              r--;
-
           // Decrease reduction if position is or has been on the PV
           // and node is not likely to fail low. (~3 Elo)
           if (   ss->ttPv