2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
5 Stockfish is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 Stockfish is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 //Definition of input features HalfKP of NNUE evaluation function
21 #ifndef NNUE_FEATURES_HALF_KP_H_INCLUDED
22 #define NNUE_FEATURES_HALF_KP_H_INCLUDED
24 #include "../nnue_common.h"
26 #include "../../evaluate.h"
27 #include "../../misc.h"
33 namespace Stockfish::Eval::NNUE::Features {
35 // Feature HalfKP: Combination of the position of own king
36 // and the position of pieces other than kings
39 // unique number for each piece type on each square
43 PS_B_PAWN = 1 * SQUARE_NB + 1,
44 PS_W_KNIGHT = 2 * SQUARE_NB + 1,
45 PS_B_KNIGHT = 3 * SQUARE_NB + 1,
46 PS_W_BISHOP = 4 * SQUARE_NB + 1,
47 PS_B_BISHOP = 5 * SQUARE_NB + 1,
48 PS_W_ROOK = 6 * SQUARE_NB + 1,
49 PS_B_ROOK = 7 * SQUARE_NB + 1,
50 PS_W_QUEEN = 8 * SQUARE_NB + 1,
51 PS_B_QUEEN = 9 * SQUARE_NB + 1,
52 PS_NB = 10 * SQUARE_NB + 1
55 static constexpr IndexType PieceSquareIndex[COLOR_NB][PIECE_NB] = {
56 // convention: W - us, B - them
57 // viewed from other side, W and B are reversed
58 { PS_NONE, PS_W_PAWN, PS_W_KNIGHT, PS_W_BISHOP, PS_W_ROOK, PS_W_QUEEN, PS_NONE, PS_NONE,
59 PS_NONE, PS_B_PAWN, PS_B_KNIGHT, PS_B_BISHOP, PS_B_ROOK, PS_B_QUEEN, PS_NONE, PS_NONE },
60 { PS_NONE, PS_B_PAWN, PS_B_KNIGHT, PS_B_BISHOP, PS_B_ROOK, PS_B_QUEEN, PS_NONE, PS_NONE,
61 PS_NONE, PS_W_PAWN, PS_W_KNIGHT, PS_W_BISHOP, PS_W_ROOK, PS_W_QUEEN, PS_NONE, PS_NONE }
64 // Orient a square according to perspective (rotates by 180 for black)
65 static Square orient(Color perspective, Square s);
67 // Index of a feature for a given king position and another piece on some square
68 static IndexType make_index(Color perspective, Square s, Piece pc, Square ksq);
72 static constexpr const char* Name = "HalfKP(Friend)";
74 // Hash value embedded in the evaluation file
75 static constexpr std::uint32_t HashValue = 0x5D69D5B8u;
77 // Number of feature dimensions
78 static constexpr IndexType Dimensions =
79 static_cast<IndexType>(SQUARE_NB) * static_cast<IndexType>(PS_NB);
81 // Maximum number of simultaneously active features. 30 because kins are not included.
82 static constexpr IndexType MaxActiveDimensions = 30;
84 // Get a list of indices for active features
85 static void append_active_indices(
88 ValueListInserter<IndexType> active);
90 // Get a list of indices for recently changed features
91 static void append_changed_indices(
95 ValueListInserter<IndexType> removed,
96 ValueListInserter<IndexType> added);
98 // Returns the cost of updating one perspective, the most costly one.
99 // Assumes no refresh needed.
100 static int update_cost(StateInfo* st);
101 static int refresh_cost(const Position& pos);
103 // Returns whether the change stored in this StateInfo means that
104 // a full accumulator refresh is required.
105 static bool requires_refresh(StateInfo* st, Color perspective);
108 } // namespace Stockfish::Eval::NNUE::Features
110 #endif // #ifndef NNUE_FEATURES_HALF_KP_H_INCLUDED