From: protonspring <mike@whiteley.org>
Date: Mon, 10 Feb 2020 22:18:16 +0000 (-0700)
Subject: Simplify Futility Move Count
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=10ead8a724671132df60ca2e23ddcad7eff7b3e5

Simplify Futility Move Count

remove two constants

STC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 62050 W: 11903 L: 11802 D: 38345
Ptnml(0-2): 1002, 7346, 14283, 7320, 1065
http://tests.stockfishchess.org/tests/view/5e41d73be70d848499f63c6d

LTC
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 12850 W: 1679 L: 1572 D: 9599
Ptnml(0-2): 82, 1171, 3818, 1249, 96
http://tests.stockfishchess.org/tests/view/5e42bf07e70d848499f63cc0

Bench: 4762351
---

diff --git a/src/search.cpp b/src/search.cpp
index f1416a74..c3ebf9ab 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -79,7 +79,7 @@ namespace {
   }
 
   constexpr int futility_move_count(bool improving, Depth depth) {
-    return (5 + depth * depth) * (1 + improving) / 2 - 1;
+    return (4 + depth * depth) / (2 - improving);
   }
 
   // History and stats update bonus, based on depth