Disable "Null driven IID" by default

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 2fdc5ad11055828c71d6b88d543b5325fd60176f..26d8fde8767a1d26971c43949db7beb648d837ca 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -107,7 +107,7 @@ namespace {
   const bool UseIIDAtNonPVNodes = false;
 
   // Use null move driven internal iterative deepening?
-  bool UseNullDrivenIID = true;
+  bool UseNullDrivenIID = false;
 
   // Internal iterative deepening margin.  At Non-PV moves, when
   // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search
@@ -1139,6 +1139,7 @@ namespace {
 
     // Null move search
     if (    allowNullmove
+        &&  depth > OnePly
         && !isCheck
         &&  ok_to_do_nullmove(pos)
         &&  approximateEval >= beta - NullMoveMargin)