From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Thu, 19 Sep 2019 18:48:16 +0000 (+0200)
Subject: Use shuffle extension only with N-move rule
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=198789c0461d4c50190ec2355cfb4932fbb85fce;p=fairystockfish.git

Use shuffle extension only with N-move rule

makruk STC
LLR: 4.58 (-2.94,2.94) [-10.00,5.00]
Total: 3656 W: 314 L: 264 D: 3078
http://35.161.250.236:6543/tests/view/5d83cf5e6e23db3768ec083c

makruk LTC
LLR: 2.95 (-2.94,2.94) [-10.00,5.00]
Total: 3645 W: 268 L: 238 D: 3139
http://35.161.250.236:6543/tests/view/5d8a510d6e23db3768ec0854
---

diff --git a/src/search.cpp b/src/search.cpp
index b9f9016..1b8c947 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1019,6 +1019,7 @@ moves_loop: // When in check, search starts from here
 
       // Shuffle extension
       else if (   PvNode
+               && pos.n_move_rule()
                && pos.rule50_count() > 18
                && depth < 3 * ONE_PLY
                && ++thisThread->shuffleExts < thisThread->nodes.load(std::memory_order_relaxed) / 4)  // To avoid too many extensions
diff --git a/src/variants.ini b/src/variants.ini
index ad74299..4150113 100644
--- a/src/variants.ini
+++ b/src/variants.ini
@@ -233,3 +233,4 @@ castling = false
 stalemateValue = draw
 immobilityIllegal = false
 connectN = 4
+nMoveRule = 0