/*

Stockfish, a UCI chess playing engine derived from Glaurung 2.1

Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)

Stockfish is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

Stockfish is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see <http://www.gnu.org/licenses/>.

*/

#include "psqt.h"

#include <algorithm>

#include "bitboard.h"

#include "types.h"

namespace Stockfish {

namespace

{

auto constexpr S = make_score;

// 'Bonus' contains Piece-Square parameters.

// Scores are explicit for files A to D, implicitly mirrored for E to H.

constexpr Score Bonus[][RANK_NB][int(FILE_NB) / 2] = {

{ },

{ },

{ // Knight

{ S(-175, -96), S(-92,-65), S(-74,-49), S(-73,-21) },

{ S( -77, -67), S(-41,-54), S(-27,-18), S(-15, 8) },

{ S( -61, -40), S(-17,-27), S( 6, -8), S( 12, 29) },

{ S( -35, -35), S( 8, -2), S( 40, 13), S( 49, 28) },

{ S( -34, -45), S( 13,-16), S( 44, 9), S( 51, 39) },

{ S( -9, -51), S( 22,-44), S( 58,-16), S( 53, 17) },

{ S( -67, -69), S(-27,-50), S( 4,-51), S( 37, 12) },

{ S(-201,-100), S(-83,-88), S(-56,-56), S(-26,-17) }

},

{ // Bishop

{ S(-37,-40), S(-4 ,-21), S( -6,-26), S(-16, -8) },

{ S(-11,-26), S( 6, -9), S( 13,-12), S( 3, 1) },

{ S(-5 ,-11), S( 15, -1), S( -4, -1), S( 12, 7) },

{ S(-4 ,-14), S( 8, -4), S( 18, 0), S( 27, 12) },

{ S(-8 ,-12), S( 20, -1), S( 15,-10), S( 22, 11) },

{ S(-11,-21), S( 4, 4), S( 1, 3), S( 8, 4) },

{ S(-12,-22), S(-10,-14), S( 4, -1), S( 0, 1) },

{ S(-34,-32), S( 1,-29), S(-10,-26), S(-16,-17) }

},

{ // Rook

{ S(-31, -9), S(-20,-13), S(-14,-10), S(-5, -9) },

{ S(-21,-12), S(-13, -9), S( -8, -1), S( 6, -2) },

{ S(-25, 6), S(-11, -8), S( -1, -2), S( 3, -6) },

{ S(-13, -6), S( -5, 1), S( -4, -9), S(-6, 7) },

{ S(-27, -5), S(-15, 8), S( -4, 7), S( 3, -6) },

{ S(-22, 6), S( -2, 1), S( 6, -7), S(12, 10) },

{ S( -2, 4), S( 12, 5), S( 16, 20), S(18, -5) },

{ S(-17, 18), S(-19, 0), S( -1, 19), S( 9, 13) }

},

{ // Queen

{ S( 3,-69), S(-5,-57), S(-5,-47), S( 4,-26) },

{ S(-3,-54), S( 5,-31), S( 8,-22), S(12, -4) },

{ S(-3,-39), S( 6,-18), S(13, -9), S( 7, 3) },

{ S( 4,-23), S( 5, -3), S( 9, 13), S( 8, 24) },

{ S( 0,-29), S(14, -6), S(12, 9), S( 5, 21) },

{ S(-4,-38), S(10,-18), S( 6,-11), S( 8, 1) },

{ S(-5,-50), S( 6,-27), S(10,-24), S( 8, -8) },

{ S(-2,-74), S(-2,-52), S( 1,-43), S(-2,-34) }

},

{ // King

{ S(271, 1), S(327, 45), S(271, 85), S(198, 76) },

{ S(278, 53), S(303,100), S(234,133), S(179,135) },

{ S(195, 88), S(258,130), S(169,169), S(120,175) },

{ S(164,103), S(190,156), S(138,172), S( 98,172) },

{ S(154, 96), S(179,166), S(105,199), S( 70,199) },

{ S(123, 92), S(145,172), S( 81,184), S( 31,191) },

{ S( 88, 47), S(120,121), S( 65,116), S( 33,131) },

{ S( 59, 11), S( 89, 59), S( 45, 73), S( -1, 78) }

}

};

constexpr Score PBonus[RANK_NB][FILE_NB] =

{ // Pawn (asymmetric distribution)

{ },

{ S( 2, -8), S( 4, -6), S( 11, 9), S( 18, 5), S( 16, 16), S( 21, 6), S( 9, -6), S( -3,-18) },

{ S( -9, -9), S(-15, -7), S( 11,-10), S( 15, 5), S( 31, 2), S( 23, 3), S( 6, -8), S(-20, -5) },

{ S( -3, 7), S(-20, 1), S( 8, -8), S( 19, -2), S( 39,-14), S( 17,-13), S( 2,-11), S( -5, -6) },

{ S( 11, 12), S( -4, 6), S(-11, 2), S( 2, -6), S( 11, -5), S( 0, -4), S(-12, 14), S( 5, 9) },

{ S( 3, 27), S(-11, 18), S( -6, 19), S( 22, 29), S( -8, 30), S( -5, 9), S(-14, 8), S(-11, 14) },

{ S( -7, -1), S( 6,-14), S( -2, 13), S(-11, 22), S( 4, 24), S(-14, 17), S( 10, 7), S( -9, 7) }

};

} // namespace

namespace PSQT

{

Score psq[PIECE_NB][SQUARE_NB];

// PSQT::init() initializes piece-square tables: the white halves of the tables are

// copied from Bonus[] and PBonus[], adding the piece value, then the black halves of

// the tables are initialized by flipping and changing the sign of the white scores.

void init() {

for (Piece pc : {W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING})

{

Score score = make_score(PieceValue[MG][pc], PieceValue[EG][pc]);

for (Square s = SQ_A1; s <= SQ_H8; ++s)

{

File f = File(edge_distance(file_of(s)));

psq[ pc][s] = score + (type_of(pc) == PAWN ? PBonus[rank_of(s)][file_of(s)]

: Bonus[pc][rank_of(s)][f]);

psq[~pc][flip_rank(s)] = -psq[pc][s];

}

}

}

} // namespace PSQT

} // namespace Stockfish