X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=a5b07d2f18c30185d2da0192076dd612578a0480;hp=394f228fb4f59956914ab3d014b199934d245716;hb=1463881153a20690871086208eaf76f20041effb;hpb=29bc1283841c8a935796159c6d3093ec879c246f

diff --git a/src/search.cpp b/src/search.cpp
index 394f228f..a5b07d2f 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -514,10 +514,16 @@ namespace {
     Thread* thisThread = pos.this_thread();
     inCheck = pos.checkers();
     moveCount = captureCount = quietCount = ss->moveCount = 0;
-    ss->statScore = 0;
     bestValue = -VALUE_INFINITE;
     maxValue = VALUE_INFINITE;
 
+    // Initialize statScore to zero for the childs of the current position.
+    // So statScore is shared between sibling positions and only the first sibling
+    // starts with statScore = 0. Later siblings start with the last calculated
+    // statScore of the previous sibling. This influences in LMR the reduction rules
+    // which based on the statScore of parent position.
+    (ss+1)->statScore = 0;
+
     // Check for the available remaining time
     if (thisThread == Threads.main())
         static_cast<MainThread*>(thisThread)->check_time();