From: protonspring <mike@whiteley.org>
Date: Tue, 27 Mar 2018 15:29:56 +0000 (+0200)
Subject: Simplification: remove pawn shelter/storm masks
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=29070bd01a5a8e37658866ead1fbdeacc60ce9a6;hp=367304e930e967d90523025b34f25c2a9b60de8f

Simplification: remove pawn shelter/storm masks

Encode the pawn shelter/storm masks into the danger score

This highly specialized rule directly contradicts the VERY high
danger score for blocked pawns. Reducing the danger score for
blocked pawns and removing this rule is apparently an effective
compromise.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 36597 W: 7522 L: 7429 D: 21646
http://tests.stockfishchess.org/tests/view/5ab935f30ebc5902932cc016

LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 100690 W: 15373 L: 15372 D: 69945
http://tests.stockfishchess.org/tests/view/5ab9501f0ebc5902932cc042

Closes https://github.com/official-stockfish/Stockfish/pull/1514

Bench: 5980822
---

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 56f5d723..24abec0c 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -68,10 +68,10 @@ namespace {
       { V( 1),  V(  64), V( 143), V(26), V(13) },
       { V( 1),  V(  47), V( 110), V(44), V(24) },
       { V( 0),  V(  72), V( 127), V(50), V(31) } },
-    { { V( 0),  V(   0), V(  79), V(23), V( 1) },  // BlockedByPawn
-      { V( 0),  V(   0), V( 148), V(27), V( 2) },
-      { V( 0),  V(   0), V( 161), V(16), V( 1) },
-      { V( 0),  V(   0), V( 171), V(22), V(15) } },
+    { { V( 0),  V(   0), V(  19), V(23), V( 1) },  // BlockedByPawn
+      { V( 0),  V(   0), V(  88), V(27), V( 2) },
+      { V( 0),  V(   0), V( 101), V(16), V( 1) },
+      { V( 0),  V(   0), V( 111), V(22), V(15) } },
     { { V(22),  V(  45), V( 104), V(62), V( 6) },  // Unblocked
       { V(31),  V(  30), V(  99), V(39), V(19) },
       { V(23),  V(  29), V(  96), V(41), V(15) },
@@ -237,12 +237,6 @@ template<Color Us>
 Value Entry::shelter_storm(const Position& pos, Square ksq) {
 
   constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
-  constexpr Bitboard ShelterMask =
-                Us == WHITE ? make_bitboard(SQ_A2, SQ_B3, SQ_C2, SQ_F2, SQ_G3, SQ_H2)
-                            : make_bitboard(SQ_A7, SQ_B6, SQ_C7, SQ_F7, SQ_G6, SQ_H7);
-  constexpr Bitboard StormMask =
-                Us == WHITE ? make_bitboard(SQ_A3, SQ_C3, SQ_F3, SQ_H3)
-                            : make_bitboard(SQ_A6, SQ_C6, SQ_F6, SQ_H6);
 
   enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
 
@@ -271,9 +265,6 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
                  [d][rkThem];
   }
 
-  if (popcount((ourPawns & ShelterMask) | (theirPawns & StormMask)) == 5)
-      safety += Value(300);
-
   return safety;
 }