From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Thu, 20 Dec 2018 15:55:37 +0000 (+0100)
Subject: Disable probcut for clobber
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=7cc4d60deaeeca2899b34db6aef65dfa5f1fc13c;p=fairystockfish.git

Disable probcut for clobber

clobber
ELO: 32.05 +-21.6 (95%) LOS: 99.8%
Total: 1000 W: 546 L: 454 D: 0
---

diff --git a/src/search.cpp b/src/search.cpp
index 02fb029..0439919 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -805,6 +805,7 @@ namespace {
     // much above beta, we can (almost) safely prune the previous move.
     if (   !PvNode
         &&  depth >= 5 * ONE_PLY
+        &&  (pos.pieces() ^ pos.pieces(CLOBBER_PIECE))
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY)
     {
         Value rbeta = std::min(beta + 216 * (1 + !!pos.max_check_count() + (pos.extinction_value() != VALUE_NONE)) - 48 * improving, VALUE_INFINITE);