Double Impact of Gain tables

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 8ef2513dd1a895c0fdda2ed28af7c5587f06de51..5ff23ad0fd894791c7b5e8ac625246c40343e1e5 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -745,7 +745,7 @@ namespace {
         && ttMove == MOVE_NONE
         && (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta)))
     {
-        Depth d = (PvNode ? depth - 2 * ONE_PLY : depth - 4 * ONE_PLY);
+        Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
 
         ss->skipNullMove = true;
         search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d);
@@ -856,7 +856,8 @@ split_point_start: // At split points actual search starts from here
           && !captureOrPromotion
           && !inCheck
           && !dangerous
-          &&  move != ttMove)
+          &&  move != ttMove
+          &&  bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           // Move count based pruning
           if (   depth < 16 * ONE_PLY
@@ -874,13 +875,18 @@ split_point_start: // At split points actual search starts from here
           // but fixing this made program slightly weaker.
           Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
           futilityValue =  ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
-                         + Gain[pos.piece_moved(move)][to_sq(move)];
+                         + 2 * Gain[pos.piece_moved(move)][to_sq(move)];
 
           if (futilityValue < beta)
           {
+              bestValue = std::max(bestValue, futilityValue);
+
               if (SpNode)
+              {
                   splitPoint->mutex.lock();
-
+                  if (bestValue > splitPoint->bestValue)
+                      splitPoint->bestValue = bestValue;
+              }
               continue;
           }