From: 31m059 <37052095+31m059@users.noreply.github.com>
Date: Sat, 15 Dec 2018 06:55:25 +0000 (-0500)
Subject: Use stronglyProtected
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=7240a90bf9be3f39f3ca4f34921dd644c5cebb3a

Use stronglyProtected

~stronglyProtected is quite similar to ~attackedBy[Them][PAWN] & ~attackedBy2[Them],
the only difference appears to be that the former includes squares attacked twice
by both sides. The resulting logic is simpler, and the change appears to be at least
Elo-neutral at both STC and LTC.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 35924 W: 7978 L: 7885 D: 20061
http://tests.stockfishchess.org/tests/view/5c14a5c00ebc5902ba11ed72

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 37078 W: 6125 L: 6030 D: 24923
http://tests.stockfishchess.org/tests/view/5c14ae880ebc5902ba11eed8

Bench: 3646542
---

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index b58d4a03..333d04ac 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -560,8 +560,7 @@ namespace {
 
     // Bonus for restricting their piece moves
     restricted =   attackedBy[Them][ALL_PIECES]
-                & ~attackedBy[Them][PAWN]
-                & ~attackedBy2[Them]
+                & ~stronglyProtected
                 &  attackedBy[Us][ALL_PIECES];
     score += RestrictedPiece * popcount(restricted);