Simplify null move search condition

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 9a2bd41565911c1bd1179df7d074a20b72ed0846..65e496b88ab66fd29ee5da329597343ccc92f114 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -673,7 +673,7 @@ namespace {
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
         && ss->ttHit
-        && tte->depth() >= depth
+        && tte->depth() > depth
         && ttValue != VALUE_NONE // Possible in case of TT access race
         && (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
                             : (tte->bound() & BOUND_UPPER)))
@@ -787,11 +787,7 @@ namespace {
     }
     else
     {
-        // In case of null move search use previous static eval with a different sign
-        if ((ss-1)->currentMove != MOVE_NULL)
-            ss->staticEval = eval = evaluate(pos);
-        else
-            ss->staticEval = eval = -(ss-1)->staticEval;
+        ss->staticEval = eval = evaluate(pos);
 
         // Save static evaluation into transposition table
         if(!excludedMove)
@@ -829,7 +825,7 @@ namespace {
         && (ss-1)->statScore < 23767
         &&  eval >= beta
         &&  eval >= ss->staticEval
-        &&  ss->staticEval >= beta - 20 * depth - improvement / 15 + 168 * ss->ttPv + 177
+        &&  ss->staticEval >= beta - 20 * depth - improvement / 15 + 177
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@@ -893,19 +889,16 @@ namespace {
         assert(probCutBeta < VALUE_INFINITE);
 
         MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
-        int probCutCount = 0;
         bool ttPv = ss->ttPv;
         ss->ttPv = false;
 
-        while (   (move = mp.next_move()) != MOVE_NONE
-               && probCutCount < 2 + 2 * cutNode)
+        while ((move = mp.next_move()) != MOVE_NONE)
             if (move != excludedMove && pos.legal(move))
             {
                 assert(pos.capture_or_promotion(move));
                 assert(depth >= 5);
 
                 captureOrPromotion = true;
-                probCutCount++;
 
                 ss->currentMove = move;
                 ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]