Tweak history initialization

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c926c1d20649d2c460f02c53d106b71b682a5cca..99c4743174dfbb9befae87b2fecca958b2450107 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -260,6 +260,7 @@ void MainThread::search() {
       bestThread = Threads.get_best_thread();
 
   bestPreviousScore = bestThread->rootMoves[0].score;
+  bestPreviousAverageScore = bestThread->rootMoves[0].averageScore;
 
   // Send again PV info if we have a new best thread
   if (bestThread != this)
@@ -489,7 +490,8 @@ void Thread::search() {
           && !Threads.stop
           && !mainThread->stopOnPonderhit)
       {
-          double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue)
+          double fallingEval = (142 + 6 * (mainThread->bestPreviousScore - bestValue)
+                                    + 6 * (mainThread->bestPreviousAverageScore - bestValue)
                                     + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
           fallingEval = std::clamp(fallingEval, 0.5, 1.5);
 
@@ -1065,6 +1067,8 @@ moves_loop: // When in check, search starts here
 
               history += thisThread->mainHistory[us][from_to(move)];
 
+              lmrDepth = std::max(0, lmrDepth - (beta - alpha < thisThread->rootDelta / 4));
+
               // Futility pruning: parent node (~5 Elo)
               if (   !ss->inCheck
                   && lmrDepth < 8
@@ -1185,9 +1189,8 @@ moves_loop: // When in check, search starts here
               && !likelyFailLow)
               r -= 2;
 
-          // Increase reduction at non-PV nodes when the best move does not change frequently
-          if (  !PvNode
-              && thisThread->bestMoveChanges <= 2)
+          // Increase reduction at non-PV nodes
+          if (!PvNode)
               r++;
 
           // Decrease reduction if opponent's move count is high (~1 Elo)