Check for easy move just once

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index ab88142ff8fe305de9a23889afc0b772ad777efa..cff8e768a73693ec3ec29046165602aac7fd404c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -44,7 +44,6 @@ namespace Search {
   Color RootColor;
   Time::point SearchTime;
   StateStackPtr SetupStates;
-  MovesVectPtr SetupMoves;
 }
 
 using std::string;
@@ -294,6 +293,7 @@ namespace {
     Stack ss[MAX_PLY_PLUS_2];
     int depth, prevBestMoveChanges;
     Value bestValue, alpha, beta, delta;
+    bool triedEasyMove = false;
 
     memset(ss, 0, 4 * sizeof(Stack));
     depth = BestMoveChanges = 0;
@@ -440,10 +440,12 @@ namespace {
             // Stop search early if one move seems to be much better than others
             if (    depth >= 12
                 && !stop
+                && !triedEasyMove
                 &&  PVSize == 1
                 && (   RootMoves.size() == 1
                     || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
             {
+                triedEasyMove = true;
                 Value rBeta = bestValue - 2 * PawnValueMg;
                 (ss+1)->excludedMove = RootMoves[0].pv[0];
                 (ss+1)->skipNullMove = true;
@@ -853,14 +855,14 @@ split_point_start: // At split points actual search starts from here
       newDepth = depth - ONE_PLY + ext;
 
       // Step 13. Futility pruning (is omitted in PV nodes)
-      if (   !captureOrPromotion
+      if (   !PvNode
+          && !captureOrPromotion
           && !inCheck
           && !dangerous
           &&  move != ttMove)
       {
           // Move count based pruning
-          if (   !PvNode
-              && depth < 16 * ONE_PLY
+          if (   depth < 16 * ONE_PLY
               && moveCount >= FutilityMoveCounts[depth]
               && (!threatMove || !refutes(pos, move, threatMove)))
           {
@@ -877,7 +879,7 @@ split_point_start: // At split points actual search starts from here
           futilityValue =  ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
                          + Gain[pos.piece_moved(move)][to_sq(move)];
 
-          if (!PvNode && futilityValue < beta)
+          if (futilityValue < beta)
           {
               if (SpNode)
                   splitPoint->mutex.lock();
@@ -886,7 +888,7 @@ split_point_start: // At split points actual search starts from here
           }
 
           // Prune moves with negative SEE at low depths
-          if (   predictedDepth < 2 * ONE_PLY
+          if (   predictedDepth < 3 * ONE_PLY
               && pos.see_sign(move) < 0)
           {
               if (SpNode)