Widen the aspiration window for larger evals

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 71634c56a8567e634648bad2f7d53fb2436410f3..14de2377b142c06ead3aa642683f9de583586be2 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -380,7 +380,7 @@ void Thread::search() {
           if (rootDepth >= 4)
           {
               Value prev = rootMoves[pvIdx].previousScore;
-              delta = Value(17);
+              delta = Value(17) + int(prev) * prev / 16384;
               alpha = std::max(prev - delta,-VALUE_INFINITE);
               beta  = std::min(prev + delta, VALUE_INFINITE);
 
@@ -825,7 +825,7 @@ namespace {
         && (ss-1)->statScore < 23767
         &&  eval >= beta
         &&  eval >= ss->staticEval
-        &&  ss->staticEval >= beta - 20 * depth - improvement / 15 + 177
+        &&  ss->staticEval >= beta - 20 * depth - improvement / 15 + 204
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@@ -1159,10 +1159,9 @@ moves_loop: // When in check, search starts here
       // cases where we extend a son if it has good chances to be "interesting".
       if (    depth >= 3
           &&  moveCount > 1 + 2 * rootNode
-          && (  !captureOrPromotion
-              || (cutNode && (ss-1)->moveCount > 1)
-              || !ss->ttPv)
-          && (!PvNode || ss->ply > 1 || thisThread->id() % 4 != 3))
+          && (   !ss->ttPv
+              || !captureOrPromotion
+              || (cutNode && (ss-1)->moveCount > 1)))
       {
           Depth r = reduction(improving, depth, moveCount, rangeReduction > 2);
 
@@ -1211,8 +1210,7 @@ moves_loop: // When in check, search starts here
           // are really negative and movecount is low, we allow this move to be searched
           // deeper than the first move (this may lead to hidden double extensions).
           int deeper =   r >= -1             ? 0
-                       : moveCount <= 3      ? 2
-                       : moveCount <= 5      ? 1
+                       : moveCount <= 5      ? 2
                        : PvNode && depth > 6 ? 1
                        :                       0;