/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2016 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
// Backward pawn penalty by opposed flag
const Score Backward[2] = { S(67, 42), S(49, 24) };
-
- // Unsupported pawn penalty, for pawns which are neither isolated or backward
- const Score Unsupported = S(20, 10);
+
+ // Unsupported pawn penalty for pawns which are neither isolated or backward,
+ // by number of pawns it supports [less than 2 / exactly 2].
+ const Score Unsupported[2] = { S(20, 10), S(25, 15) };
// Connected pawn bonus by opposed, phalanx, twice supported and rank
Score Connected[2][2][2][RANK_NB];
-
+
// Doubled pawn penalty by file
const Score Doubled[FILE_NB] = {
S(13, 43), S(20, 48), S(23, 48), S(23, 48),
S( 0, 0), S( 0, 0), S(0, 0), S(0, 0),
S(20, 20), S(40, 40), S(0, 0), S(0, 0) };
- // Center bind bonus, when two pawns controls the same central square
- const Score CenterBind = S(16, 0);
-
// Weakness of our pawn shelter in front of the king by [distance from edge][rank]
const Value ShelterWeakness[][RANK_NB] = {
{ V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
- const Bitboard CenterBindMask =
- Us == WHITE ? (FileDBB | FileEBB) & (Rank5BB | Rank6BB | Rank7BB)
- : (FileDBB | FileEBB) & (Rank4BB | Rank3BB | Rank2BB);
-
Bitboard b, neighbours, doubled, supported, phalanx;
Square s;
bool passed, isolated, opposed, backward, lever, connected;
score -= Backward[opposed];
else if (!supported)
- score -= Unsupported;
+ score -= Unsupported[more_than_one(neighbours & rank_bb(s + Up))];
if (connected)
score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
b = e->semiopenFiles[Us] ^ 0xFF;
e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
- b = shift_bb<Right>(ourPawns) & shift_bb<Left>(ourPawns) & CenterBindMask;
- score += CenterBind * popcount<Max15>(b);
-
return score;
}