Simplify reduction for consecutive fails

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6e1d2b5321a96e4332fa0cc689fe5921703414ae..f8f956fa9375241536e3a61eadc23eff83e1b467 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -377,7 +377,7 @@ void Thread::search() {
           // Start with a small aspiration window and, in the case of a fail
           // high/low, re-search with a bigger window until we don't fail
           // high/low anymore.
-          failedHighCnt = 0;
+          int failedHighCnt = 0;
           while (true)
           {
               Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt - searchAgainCounter);
@@ -767,7 +767,7 @@ namespace {
         if ((ss-1)->currentMove != MOVE_NULL)
             ss->staticEval = eval = evaluate(pos);
         else
-            ss->staticEval = eval = -(ss-1)->staticEval + 2 * Tempo;
+            ss->staticEval = eval = -(ss-1)->staticEval;
 
         // Save static evaluation into transposition table
         tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
@@ -776,7 +776,7 @@ namespace {
     // Use static evaluation difference to improve quiet move ordering
     if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture)
     {
-        int bonus = std::clamp(-depth * 4 * int((ss-1)->staticEval + ss->staticEval - 2 * Tempo), -1000, 1000);
+        int bonus = std::clamp(-depth * 4 * int((ss-1)->staticEval + ss->staticEval), -1000, 1000);
         thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus;
     }
 
@@ -1157,10 +1157,6 @@ moves_loop: // When in check, search starts from here
               if (ttCapture)
                   r++;
 
-              // Increase reduction at root if failing high
-              if (rootNode)
-                  r += thisThread->failedHighCnt * thisThread->failedHighCnt * moveCount / 512;
-
               // Increase reduction for cut nodes (~3 Elo)
               if (cutNode)
                   r += 2;
@@ -1436,7 +1432,7 @@ moves_loop: // When in check, search starts from here
             // and addition of two tempos
             ss->staticEval = bestValue =
             (ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
-                                             : -(ss-1)->staticEval + 2 * Tempo;
+                                             : -(ss-1)->staticEval;
 
         // Stand pat. Return immediately if static value is at least beta
         if (bestValue >= beta)