From 1e9397a2df3094589540838b4e24342ac53c212a Mon Sep 17 00:00:00 2001 From: joergoster Date: Sun, 24 Jun 2018 17:07:38 +0200 Subject: [PATCH] Simplify KingProtector penalty. Recent tuning results implied this penalty is more important for knights and bishops, and almost negligible for rooks and queen. Passed as simplification both STC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 20873 W: 4592 L: 4469 D: 11812 http://tests.stockfishchess.org/tests/view/5b2fb4d00ebc5902b2e57e84 and LTC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 46069 W: 7949 L: 7870 D: 30250 http://tests.stockfishchess.org/tests/view/5b2fcc4b0ebc5902b2e580c5 Closes https://github.com/official-stockfish/Stockfish/pull/1660 Bench: 5487679 --- src/evaluate.cpp | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 42ce5258..0130b057 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -158,8 +158,8 @@ namespace { // PassedDanger[Rank] contains a term to weight the passed score constexpr int PassedDanger[RANK_NB] = { 0, 0, 0, 2, 7, 12, 19 }; - // KingProtector[PieceType-2] contains a penalty according to distance from king - constexpr Score KingProtector[] = { S(4, 6), S(6, 3), S(1, 0), S(0, -2) }; + // KingProtector[knight/bishop] contains a penalty according to distance from king + constexpr Score KingProtector[] = { S(4, 6), S(6, 3) }; // Assorted bonuses and penalties constexpr Score BishopPawns = S( 3, 5); @@ -330,9 +330,6 @@ namespace { mobility[Us] += MobilityBonus[Pt - 2][mob]; - // Penalty if the piece is far from the king - score -= KingProtector[Pt - 2] * distance(s, pos.square(Us)); - if (Pt == BISHOP || Pt == KNIGHT) { // Bonus if piece is on an outpost square or can reach one @@ -348,6 +345,9 @@ namespace { && (pos.pieces(PAWN) & (s + pawn_push(Us)))) score += MinorBehindPawn; + // Penalty if the piece is far from the king + score -= KingProtector[Pt == BISHOP] * distance(s, pos.square(Us)); + if (Pt == BISHOP) { // Penalty according to number of pawns on the same color square as the -- 2.39.2