From: Michael Chaly <Vizvezdenec@gmail.com>
Date: Sun, 6 Aug 2023 23:32:38 +0000 (+0300)
Subject: Adjust futility pruning base in qsearch
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=5c2111cc30b283aa5b7e1cc1c1e9d7c52e1e910b

Adjust futility pruning base in qsearch

Current master used value from transposition table there if it existed,
this patch uses minimum between this tt value and the static eval instead
(this thus is closer to the main search function, which uses the static eval).

Passed STC:
https://tests.stockfishchess.org/tests/view/64cd57285b17f7c21c0d6a8c
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 252544 W: 64671 L: 64039 D: 123834
Ptnml(0-2): 839, 29207, 65575, 29785, 866

Passed LTC:
https://tests.stockfishchess.org/tests/view/64cf6c915b17f7c21c0d9fcb
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 60150 W: 15374 L: 15012 D: 29764
Ptnml(0-2): 24, 6321, 17024, 6681, 25

closes https://github.com/official-stockfish/Stockfish/pull/4725

Bench: 1573024
---

diff --git a/src/search.cpp b/src/search.cpp
index dc439ed0..24f54c32 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1495,7 +1495,7 @@ moves_loop: // When in check, search starts here
         if (bestValue > alpha)
             alpha = bestValue;
 
-        futilityBase = bestValue + 200;
+        futilityBase = std::min(ss->staticEval, bestValue) + 200;
     }
 
     const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,