Simplify depth reduction in IID.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 7c9c1b6936bfc9220f0b7be372e969a529ee2fd8..8415e24d7434200fae4a5998404fb1f4b6ef8f8a 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -834,8 +834,7 @@ namespace {
     if (    depth >= 8 * ONE_PLY
         && !ttMove)
     {
-        Depth d = 3 * depth / 4 - 2 * ONE_PLY;
-        search<NT>(pos, ss, alpha, beta, d, cutNode);
+        search<NT>(pos, ss, alpha, beta, depth - 7 * ONE_PLY, cutNode);
 
         tte = TT.probe(posKey, ttHit);
         ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;