From afe45fbc404e055b9848984d03f896f1fb4fd3ea Mon Sep 17 00:00:00 2001
From: Topologist <thelisting@web.de>
Date: Fri, 17 Sep 2021 12:08:52 +0200
Subject: [PATCH] Try new strategy to limit double extensions bench 6217697

---
 src/search.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index 0c05713c165..38435c3e71d 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1069,10 +1069,10 @@ namespace {
               extension = 1;
               singularQuietLMR = !ttCapture;
 
-              // Avoid search explosion by limiting the number of double extensions to at most 3
+              // Avoid search explosion by limiting the number of double extensions
               if (   !PvNode
-                  && value < singularBeta - 93
-                  && ss->doubleExtensions < 3)
+                  && value < singularBeta - 51 - 50*std::min(1,ss->doubleExtensions)
+                  && ss->doubleExtensions <= 5)
               {
                   extension = 2;
                   doubleExtension = true;