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Good bishops on the main diagonals

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Bonus in midgame for bishops on long diagonals when the central squares are not occupied by pawns.

Author: ElbertoOne

Passed STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 10801 W: 1955 L: 1786 D: 7060
http://tests.stockfishchess.org/tests/view/59cf5c1d0ebc5916ff64b9da

and LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 83978 W: 10685 L: 10303 D: 62990
http://tests.stockfishchess.org/tests/view/59cf6f6c0ebc5916ff64b9e4

Bench: 5620312
This commit is contained in:
Stéphane Nicolet 2017-10-02 00:41:06 +02:00 • committed by Marco Costalba
parent 07b5a28a68
commit 452e5154cf
1 changed files with 20 additions and 9 deletions
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29
src/evaluate.cpp
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@ -31,6 +31,16 @@
namespace {
const Bitboard LongDiagonals = 0x8142241818244281ULL; // A1..H8 | H1..A8
const Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
const Bitboard KingFlank[FILE_NB] = {
QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
};
namespace Trace {
enum Tracing {NO_TRACE, TRACE};
@ -204,6 +214,7 @@ namespace {
// Assorted bonuses and penalties used by evaluation
const Score MinorBehindPawn = S( 16, 0);
const Score BishopPawns = S( 8, 12);
const Score LongRangedBishop = S( 22, 0);
const Score RookOnPawn = S( 8, 24);
const Score TrappedRook = S( 92, 0);
const Score WeakQueen = S( 50, 10);
@ -338,10 +349,18 @@ namespace {
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
// Penalty for pawns on the same color square as the bishop
if (Pt == BISHOP)
{
// Penalty for pawns on the same color square as the bishop
score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);
// Bonus for bishop on a long diagonal without pawns in the center
if ( (LongDiagonals & s)
&& !(attackedBy[Them][PAWN] & s)
&& !(Center & PseudoAttacks[BISHOP][s] & pos.pieces(PAWN)))
score += LongRangedBishop;
}
// An important Chess960 pattern: A cornered bishop blocked by a friendly
// pawn diagonally in front of it is a very serious problem, especially
// when that pawn is also blocked.
@ -396,14 +415,6 @@ namespace {
// evaluate_king() assigns bonuses and penalties to a king of a given color
const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
const Bitboard KingFlank[FILE_NB] = {
QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
};
template<Tracing T> template<Color Us>
Score Evaluation<T>::evaluate_king() {