From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Sat, 26 Jan 2019 09:54:25 +0000 (+0100)
Subject: Disable futility pruning for racing kings
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=147afebc22bc188b0f195625b96bbdbee4213945;p=fairystockfish.git

Disable futility pruning for racing kings

racingkings STC
LLR: 2.95 (-2.94,2.94) [0.00,10.00]
Total: 350 W: 163 L: 81 D: 106
http://35.161.250.236:6543/tests/view/5c4b86806e23db07348e8601

racingkings LTC
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 391 W: 174 L: 92 D: 125
http://35.161.250.236:6543/tests/view/5c4b97676e23db07348e8609
---

diff --git a/src/search.cpp b/src/search.cpp
index c21f317..87c330e 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -745,6 +745,7 @@ namespace {
         &&  depth < 7 * ONE_PLY
         && !(   pos.extinction_value() == -VALUE_MATE
              && pos.extinction_piece_types().find(ALL_PIECES) == pos.extinction_piece_types().end())
+        && (pos.checking_permitted() || !pos.capture_the_flag_piece())
         &&  eval - futility_margin(depth, improving) * (1 + !!pos.max_check_count()) >= beta
         &&  eval < VALUE_KNOWN_WIN) // Do not return unproven wins
         return eval;