2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #if !defined(EVALUATE_H_INCLUDED)
22 #define EVALUATE_H_INCLUDED
39 /// The EvalInfo struct contains various information computed and collected
40 /// by the evaluation function. An EvalInfo object is passed as one of the
41 /// arguments to the evaluation function, and the search can make use of its
42 /// contents to make intelligent search decisions.
44 /// At the moment, this is not utilized very much: The only part of the
45 /// EvalInfo object which is used by the search is margin.
50 // Middle and end game position's static evaluations
53 // margin[color] stores the evaluation margins we should consider for
54 // the given position. This is a kind of uncertainty estimation and
55 // typically is used by the search for pruning decisions.
58 // Pointers to material and pawn hash table entries
62 // attackedBy[color][piece type] is a bitboard representing all squares
63 // attacked by a given color and piece type, attackedBy[color][0] contains
64 // all squares attacked by the given color.
65 Bitboard attackedBy[2][8];
67 // kingZone[color] is the zone around the enemy king which is considered
68 // by the king safety evaluation. This consists of the squares directly
69 // adjacent to the king, and the three (or two, for a king on an edge file)
70 // squares two ranks in front of the king. For instance, if black's king
71 // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
72 // f7, g7, h7, f6, g6 and h6.
75 // kingAttackersCount[color] is the number of pieces of the given color
76 // which attack a square in the kingZone of the enemy king.
77 int kingAttackersCount[2];
79 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
80 // given color which attack a square in the kingZone of the enemy king. The
81 // weights of the individual piece types are given by the variables
82 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
83 // KnightAttackWeight in evaluate.cpp
84 int kingAttackersWeight[2];
86 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
87 // directly adjacent to the king of the given color. Pieces which attack
88 // more than one square are counted multiple times. For instance, if black's
89 // king is on g8 and there's a white knight on g5, this knight adds
90 // 2 to kingAdjacentZoneAttacksCount[BLACK].
91 int kingAdjacentZoneAttacksCount[2];
99 extern Value evaluate(const Position& pos, EvalInfo& ei);
100 extern void init_eval(int threads);
101 extern void quit_eval();
102 extern void read_weights(Color sideToMove);
105 #endif // !defined(EVALUATE_H_INCLUDED)