X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=f58baf39661190053d1dc64d01090fbacff1ad56;hp=5ff23ad0fd894791c7b5e8ac625246c40343e1e5;hb=a95cbca568ec393ea6b4b17ed86f89c75d7cbe57;hpb=36c82b751ce227c05bfb0dc74c311a469f7f8ec4

diff --git a/src/search.cpp b/src/search.cpp
index 5ff23ad0..f58baf39 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -440,6 +440,7 @@ namespace {
             if (    depth >= 12
                 && !stop
                 &&  PVSize == 1
+                &&  bestValue > VALUE_MATED_IN_MAX_PLY
                 && (   RootMoves.size() == 1
                     || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
             {
@@ -678,7 +679,7 @@ namespace {
             if (nullValue >= VALUE_MATE_IN_MAX_PLY)
                 nullValue = beta;
 
-            if (depth < 6 * ONE_PLY)
+            if (depth < 12 * ONE_PLY)
                 return nullValue;
 
             // Do verification search at high depths
@@ -875,7 +876,7 @@ 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)
-                         + 2 * Gain[pos.piece_moved(move)][to_sq(move)];
+                         + Gain[pos.piece_moved(move)][to_sq(move)];
 
           if (futilityValue < beta)
           {
@@ -1224,10 +1225,11 @@ split_point_start: // At split points actual search starts from here
               continue;
           }
 
-          // Prune moves with negative or equal SEE
+          // Prune moves with negative or equal SEE and also moves with positive
+          // SEE where capturing piece loses a tempo and SEE < beta - futilityBase.
           if (   futilityBase < beta
               && depth < DEPTH_ZERO
-              && pos.see(move) <= 0)
+              && pos.see(move, beta - futilityBase) <= 0)
           {
               bestValue = std::max(bestValue, futilityBase);
               continue;