From: xoto10 <buylow001@gmail.com>
Date: Thu, 26 Mar 2020 19:47:48 +0000 (+0000)
Subject: Remove previousScore adjustment of delta.
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=8c73339a3639f1753b2270b569532daffa7d93f5

Remove previousScore adjustment of delta.

STC:
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 14580 W: 2904 L: 2731 D: 8945
Ptnml(0-2): 243, 1665, 3339, 1762, 281
https://tests.stockfishchess.org/tests/view/5e7d080ae42a5c3b3ca2ebc6

LTC:
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 60338 W: 7870 L: 7831 D: 44637
Ptnml(0-2): 451, 5596, 18018, 5671, 433
https://tests.stockfishchess.org/tests/view/5e7d11b3e42a5c3b3ca2ebd3

closes https://github.com/official-stockfish/Stockfish/pull/2598

Bench 5247262
---

diff --git a/src/search.cpp b/src/search.cpp
index c5a7582c..f866afe5 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -433,7 +433,7 @@ void Thread::search() {
           if (rootDepth >= 4)
           {
               Value previousScore = rootMoves[pvIdx].previousScore;
-              delta = Value(21 + abs(previousScore) / 256);
+              delta = Value(21);
               alpha = std::max(previousScore - delta,-VALUE_INFINITE);
               beta  = std::min(previousScore + delta, VALUE_INFINITE);