From: Marco Costalba <mcostalba@gmail.com>
Date: Thu, 13 Jun 2013 17:50:32 +0000 (+0200)
Subject: Reduce more CUT nodes
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=4bebb15e9426ec80ee50d016a812a49a36dd82bd

Reduce more CUT nodes

We got a good result from this tweak, in line with
what was already found by Don Dailey.

At short TC:
LLR: 2.95 (-2.94,2.94)
Total: 13097 W: 2742 L: 2598 D: 7757

At long TC:
LLR: 2.97 (-2.94,2.94)
Total: 7281 W: 1408 L: 1265 D: 4608

bench: 5108393
---

diff --git a/src/search.cpp b/src/search.cpp
index 4ca9e9b8..a10e1180 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -948,6 +948,10 @@ split_point_start: // At split points actual search starts from here
           &&  move != ss->killers[1])
       {
           ss->reduction = reduction<PvNode>(depth, moveCount);
+
+          if (!PvNode && cutNode)
+              ss->reduction += ONE_PLY;
+
           if (move == countermoves[0] || move == countermoves[1])
               ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY);