From: Stefan Geschwentner <stgeschwentner@gmail.com>
Date: Fri, 10 Dec 2021 17:42:05 +0000 (+0100)
Subject: Simplify falling eval time factor.
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=d579db34a3f7a26cd5502e79dafde2a80614d645

Simplify falling eval time factor.

Remove the difference to previous best score in falling eval calculation. As compensation double the effect of the difference to previous best average score.

STC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 86944 W: 22363 L: 22285 D: 42296
Ptnml(0-2): 273, 9227, 24396, 9301, 275
https://tests.stockfishchess.org/tests/view/61b111ce06b4c2dcb1b11546

LTC:
LLR: 2.96 (-2.94,2.94) <-2.25,0.25>
Total: 134944 W: 34606 L: 34596 D: 65742
Ptnml(0-2): 66, 12941, 41456, 12935, 74
https://tests.stockfishchess.org/tests/view/61b19ca206b4c2dcb1b13a8b

closes https://github.com/official-stockfish/Stockfish/pull/3841

Bench: 4729473
---

diff --git a/src/search.cpp b/src/search.cpp
index cded8614..687bf0a9 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -490,9 +490,8 @@ void Thread::search() {
           && !Threads.stop
           && !mainThread->stopOnPonderhit)
       {
-          double fallingEval = (142 + 6 * (mainThread->bestPreviousScore - bestValue)
-                                    + 6 * (mainThread->bestPreviousAverageScore - bestValue)
-                                    + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
+          double fallingEval = (142 + 12 * (mainThread->bestPreviousAverageScore - bestValue)
+                                    +  6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
           fallingEval = std::clamp(fallingEval, 0.5, 1.5);
 
           // If the bestMove is stable over several iterations, reduce time accordingly