From 2d3258162387bf38551962bf2c9dd1d47e72b4dd Mon Sep 17 00:00:00 2001
From: Viren6 <94880762+Viren6@users.noreply.github.com>
Date: Sun, 19 May 2024 01:40:29 +0100
Subject: [PATCH] Revert "Simplify Away Quadruple Extensions"

This reverts commit 4edd1a3

The unusual result of (combined) +12.0 +- 3.7 in the 2 VVLTC simplification SPRTs ran was the result of base having only 64MB of hash instead of 512MB (Asymmetric hash).
Vizvezdenec was the one to notice this.

closes https://github.com/official-stockfish/Stockfish/pull/5265

bench 1404295

Co-Authored-By: Michael Chaly <26898827+Vizvezdenec@users.noreply.github.com>
---
 src/search.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/search.cpp b/src/search.cpp
index 54990ce6f03..cbd454efb76 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1053,9 +1053,11 @@ Value Search::Worker::search(
                     int doubleMargin = 298 * PvNode - 209 * !ttCapture;
                     int tripleMargin =
                       117 + 252 * PvNode - 270 * !ttCapture + 111 * (ss->ttPv || !ttCapture);
+                    int quadMargin = 471 + 343 * PvNode - 281 * !ttCapture + 217 * ss->ttPv;
 
                     extension = 1 + (value < singularBeta - doubleMargin)
-                              + (value < singularBeta - tripleMargin);
+                              + (value < singularBeta - tripleMargin)
+                              + (value < singularBeta - quadMargin);
 
                     depth += ((!PvNode) && (depth < 15));
                 }