From 365aa85dcea3adee21b5e01a7941b4b18fdc8194 Mon Sep 17 00:00:00 2001
From: Linmiao Xu <linmiao.xu@gmail.com>
Date: Tue, 21 May 2024 16:24:49 -0400
Subject: [PATCH] Remove material imbalance param when adjusting optimism

Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/664d033d830eb9f886616aff
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 102144 W: 26283 L: 26135 D: 49726
Ptnml(0-2): 292, 12201, 25991, 12243, 345

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/664d5c00830eb9f886616cb3
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 250032 W: 63022 L: 63036 D: 123974
Ptnml(0-2): 103, 27941, 68970, 27871, 131

closes https://github.com/official-stockfish/Stockfish/pull/5284

Bench: 1330940
---
 src/evaluate.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 4c449774..7ca470af 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -73,8 +73,8 @@ Value Eval::evaluate(const Eval::NNUE::Networks&    networks,
         smallNet = false;
     }
 
-    // Blend optimism and eval with nnue complexity and material imbalance
-    optimism += optimism * (nnueComplexity + std::abs(simpleEval - nnue)) / 620;
+    // Blend optimism and eval with nnue complexity
+    optimism += optimism * nnueComplexity / 512;
     nnue -= nnue * (nnueComplexity * 5 / 3) / 32082;
 
     v = (nnue