From ecf5646f6e8446a3498aca04723dcee2b74f2d77 Mon Sep 17 00:00:00 2001
From: Michael Chaly <Vizvezdenec@gmail.com>
Date: Fri, 1 Nov 2024 02:04:35 +0300
Subject: [PATCH] Refine definition of improving

This patch also allows improving flag to be true if static evaluation of
the position is good enough.

Passed STC:
https://tests.stockfishchess.org/tests/view/6720906086d5ee47d953d4d0
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 34816 W: 9172 L: 8858 D: 16786
Ptnml(0-2): 113, 3988, 8887, 4312, 108

Passed LTC:
https://tests.stockfishchess.org/tests/view/6721162686d5ee47d953d597
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 145374 W: 37118 L: 36574 D: 71682
Ptnml(0-2): 91, 15875, 40212, 16417, 92

closes https://github.com/official-stockfish/Stockfish/pull/5662

Bench: 1518856
---
 src/search.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/search.cpp b/src/search.cpp
index d6914da0..1b9b745c 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -795,6 +795,8 @@ Value Search::Worker::search(
         && eval < VALUE_TB_WIN_IN_MAX_PLY)
         return beta + (eval - beta) / 3;
 
+    improving |= ss->staticEval >= beta + 100;
+
     // Step 9. Null move search with verification search (~35 Elo)
     if (cutNode && (ss - 1)->currentMove != Move::null() && eval >= beta
         && ss->staticEval >= beta - 23 * depth + 400 && !excludedMove && pos.non_pawn_material(us)