From f0abde241d39ee4507778bf41b392492c5391652 Mon Sep 17 00:00:00 2001 From: protonspring Date: Sat, 25 Jul 2020 07:32:19 -0600 Subject: [PATCH] Remove conditional_more_than_two(). This is a functional simplification that removes the conditional_more_than_two() function, which was quite strange and kooky. Note the very minor change to the bench value. See this thread for relevant comments on the passing branch: protonspring/Stockfish@d89730d...ff35b50 STC LLR: 2.95 (-2.94,2.94) {-1.50,0.50} Total: 59760 W: 11411 L: 11311 D: 37038 Ptnml(0-2): 992, 6863, 14044, 7015, 966 https://tests.stockfishchess.org/tests/view/5f179988c09435d870cb9b9a LTC LLR: 2.93 (-2.94,2.94) {-1.50,0.50} Total: 45208 W: 5553 L: 5497 D: 34158 Ptnml(0-2): 315, 4081, 13761, 4127, 320 https://tests.stockfishchess.org/tests/view/5f184847c09435d870cb9bee closes https://github.com/official-stockfish/Stockfish/pull/2826 Bench: 4578290 --- src/bitboard.h | 6 ------ src/evaluate.cpp | 12 +++++++----- 2 files changed, 7 insertions(+), 11 deletions(-) diff --git a/src/bitboard.h b/src/bitboard.h index 15ec4153..8c95de8c 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -130,12 +130,6 @@ constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } -/// Counts the occupation of the bitboard depending on the occupation of SQ_A1 -/// as in `b & (1ULL << SQ_A1) ? more_than_two(b) : more_than_one(b)` - -constexpr bool conditional_more_than_two(Bitboard b) { - return b & (b - 1) & (b - 2); -} constexpr bool opposite_colors(Square s1, Square s2) { return (s1 + rank_of(s1) + s2 + rank_of(s2)) & 1; diff --git a/src/evaluate.cpp b/src/evaluate.cpp index dbb725d4..d16648a8 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -310,13 +310,15 @@ namespace { if (Pt == BISHOP || Pt == KNIGHT) { - // Bonus if piece is on an outpost square or can reach one + // Bonus if the piece is on an outpost square or can reach one + // Reduced bonus for knights (BadOutpost) if few relevant targets bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them); + Bitboard targets = pos.pieces(Them) & ~pos.pieces(PAWN); + if ( Pt == KNIGHT - && bb & s & ~CenterFiles - && !(b & pos.pieces(Them) & ~pos.pieces(PAWN)) - && !conditional_more_than_two( - pos.pieces(Them) & ~pos.pieces(PAWN) & (s & QueenSide ? QueenSide : KingSide))) + && bb & s & ~CenterFiles // on a side outpost + && !(b & targets) // no relevant attacks + && (!more_than_one(targets & (s & QueenSide ? QueenSide : KingSide)))) score += BadOutpost; else if (bb & s) score += Outpost[Pt == BISHOP]; -- 2.39.2