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Penalty for bad bishop with blocked central files

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We increase the penalty for bad bishops by a factor proportional
to the number of our blocked pawns in the center files C, D, E or F.

STC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 8868 W: 1870 L: 1700 D: 5298
http://tests.stockfishchess.org/html/live_elo.html?5ae7674f0ebc590e39268b34

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 5813 W: 950 L: 808 D: 4055
http://tests.stockfishchess.org/html/live_elo.html?5ae77bae0ebc5926dba90dd9

Closes https://github.com/official-stockfish/Stockfish/pull/1573

Bench: 5364190
This commit is contained in:
MJZ1977 2018-05-01 07:12:17 +02:00 • committed by Stéphane Nicolet
parent 213166ba22
commit 5a7cdadfb3
2 changed files with 10 additions and 4 deletions
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1
AUTHORS
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@ -85,6 +85,7 @@ Michel Van den Bergh (vdbergh)
Mikael Bäckman (mbootsector) Mikael Bäckman (mbootsector)
Mike Whiteley (protonspring) Mike Whiteley (protonspring)
Miroslav Fontán (Hexik) Miroslav Fontán (Hexik)
Moez Jellouli (MJZ1977)
Mohammed Li (tthsqe12) Mohammed Li (tthsqe12)
Nathan Rugg (nmrugg) Nathan Rugg (nmrugg)
Nicklas Persson (NicklasPersson) Nicklas Persson (NicklasPersson)

11
src/evaluate.cpp
View file

@ -162,7 +162,7 @@ namespace {
constexpr Score KingProtector[] = { S(3, 5), S(4, 3), S(3, 0), S(1, -1) }; constexpr Score KingProtector[] = { S(3, 5), S(4, 3), S(3, 0), S(1, -1) };
// Assorted bonuses and penalties // Assorted bonuses and penalties
constexpr Score BishopPawns = S( 8, 12); constexpr Score BishopPawns = S( 3, 5);
constexpr Score CloseEnemies = S( 7, 0); constexpr Score CloseEnemies = S( 7, 0);
constexpr Score Connectivity = S( 3, 1); constexpr Score Connectivity = S( 3, 1);
constexpr Score CorneredBishop = S( 50, 50); constexpr Score CorneredBishop = S( 50, 50);
@ -294,6 +294,7 @@ namespace {
Score Evaluation<T>::pieces() { Score Evaluation<T>::pieces() {
constexpr Color Them = (Us == WHITE ? BLACK : WHITE); constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
: Rank5BB | Rank4BB | Rank3BB); : Rank5BB | Rank4BB | Rank3BB);
const Square* pl = pos.squares<Pt>(Us); const Square* pl = pos.squares<Pt>(Us);
@ -349,8 +350,12 @@ namespace {
if (Pt == BISHOP) if (Pt == BISHOP)
{ {
// Penalty according to number of pawns on the same color square as the bishop // Penalty according to number of pawns on the same color square as the
score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s); // bishop, bigger when the center files are blocked with pawns.
Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s)
* (1 + popcount(blocked & CenterFiles));
// Bonus for bishop on a long diagonal which can "see" both center squares // Bonus for bishop on a long diagonal which can "see" both center squares
if (more_than_one(Center & (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) | s))) if (more_than_one(Center & (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) | s)))