Prune negative SEE moves also in PV nodes

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 74dc9e29bdb4f2fafa53eb95a1b208413d2bfa45..c039b64e48a8c6a2f005c8b62df6672ecfa0b8e6 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -182,7 +182,7 @@ void Search::think() {
   static PolyglotBook book; // Defined static to initialize the PRNG only once
 
   RootColor = RootPos.side_to_move();
-  TimeMgr.init(Limits, RootPos.startpos_ply_counter(), RootColor);
+  TimeMgr.init(Limits, RootPos.game_ply(), RootColor);
 
   if (RootMoves.empty())
   {
@@ -857,16 +857,15 @@ 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 (   !PvNode
-          && !captureOrPromotion
+      if (   !captureOrPromotion
           && !inCheck
           && !dangerous
           &&  move != ttMove
-          && (bestValue > VALUE_MATED_IN_MAX_PLY || (   bestValue == -VALUE_INFINITE
-                                                     && alpha > VALUE_MATED_IN_MAX_PLY)))
+          &&  alpha > VALUE_MATED_IN_MAX_PLY)
       {
           // Move count based pruning
-          if (   depth < 16 * ONE_PLY
+          if (   !PvNode
+              && depth < 16 * ONE_PLY
               && moveCount >= FutilityMoveCounts[depth]
               && (!threatMove || !refutes(pos, move, threatMove)))
           {
@@ -883,7 +882,7 @@ 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 (futilityValue < beta)
+          if (!PvNode && futilityValue < beta)
           {
               if (SpNode)
                   sp->mutex.lock();