Increase non-PV IID search depth

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 0416c16cb3c89a9f7606d2ea6b4dd51173f53274..8ef2513dd1a895c0fdda2ed28af7c5587f06de51 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -745,7 +745,7 @@ namespace {
         && ttMove == MOVE_NONE
         && (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta)))
     {
-        Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
+        Depth d = (PvNode ? depth - 2 * ONE_PLY : depth - 4 * ONE_PLY);
 
         ss->skipNullMove = true;
         search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d);
@@ -885,7 +885,7 @@ split_point_start: // At split points actual search starts from here
           }
 
           // Prune moves with negative SEE at low depths
-          if (   predictedDepth < 3 * ONE_PLY
+          if (   predictedDepth < 4 * ONE_PLY
               && pos.see_sign(move) < 0)
           {
               if (SpNode)