mirror of
https://github.com/HChaZZY/Stockfish.git
synced 2025-12-23 10:36:26 +08:00
255514fb29
Clarify the assumptions on the position passed to the AppendChangedIndices(). Closes https://github.com/official-stockfish/Stockfish/pull/3428 No functional change
88 lines
3.7 KiB
C++
88 lines
3.7 KiB
C++
/*
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
|
Copyright (C) 2004-2021 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/>.
|
|
*/
|
|
|
|
//Definition of input features HalfKP of NNUE evaluation function
|
|
|
|
#include "half_kp.h"
|
|
#include "index_list.h"
|
|
|
|
namespace Stockfish::Eval::NNUE::Features {
|
|
|
|
// Orient a square according to perspective (rotates by 180 for black)
|
|
inline Square orient(Color perspective, Square s) {
|
|
return Square(int(s) ^ (bool(perspective) * 63));
|
|
}
|
|
|
|
// Index of a feature for a given king position and another piece on some square
|
|
inline IndexType make_index(Color perspective, Square s, Piece pc, Square ksq) {
|
|
return IndexType(orient(perspective, s) + kpp_board_index[perspective][pc] + PS_END * ksq);
|
|
}
|
|
|
|
// Get a list of indices for active features
|
|
template <Side AssociatedKing>
|
|
void HalfKP<AssociatedKing>::AppendActiveIndices(
|
|
const Position& pos, Color perspective, IndexList* active) {
|
|
|
|
Square ksq = orient(perspective, pos.square<KING>(perspective));
|
|
Bitboard bb = pos.pieces() & ~pos.pieces(KING);
|
|
while (bb)
|
|
{
|
|
Square s = pop_lsb(bb);
|
|
active->push_back(make_index(perspective, s, pos.piece_on(s), ksq));
|
|
}
|
|
}
|
|
|
|
|
|
// AppendChangedIndices() : get a list of indices for recently changed features
|
|
|
|
// IMPORTANT: The `pos` in this function is pretty much useless as it
|
|
// is not always the position the features are updated to. The feature
|
|
// transformer code right now can update multiple accumulators per move,
|
|
// but since Stockfish only keeps the full state of the current leaf
|
|
// search position it is not possible to always pass here the position for
|
|
// which the accumulator is being updated. Therefore the only thing that
|
|
// can be reliably extracted from `pos` is the king square for the king
|
|
// of the `perspective` color (note: not even the other king's square will
|
|
// match reality in all cases, this is also the reason why `dp` is passed
|
|
// as a parameter and not extracted from pos.state()). This is of particular
|
|
// problem for future nets with other feature sets, where updating the active
|
|
// feature might require more information from the intermediate positions. In
|
|
// this case the only easy solution is to remove the multiple updates from
|
|
// the feature transformer update code and only update the accumulator for
|
|
// the current leaf position (the position after the move).
|
|
|
|
template <Side AssociatedKing>
|
|
void HalfKP<AssociatedKing>::AppendChangedIndices(
|
|
const Position& pos, const DirtyPiece& dp, Color perspective,
|
|
IndexList* removed, IndexList* added) {
|
|
|
|
Square ksq = orient(perspective, pos.square<KING>(perspective));
|
|
for (int i = 0; i < dp.dirty_num; ++i) {
|
|
Piece pc = dp.piece[i];
|
|
if (type_of(pc) == KING) continue;
|
|
if (dp.from[i] != SQ_NONE)
|
|
removed->push_back(make_index(perspective, dp.from[i], pc, ksq));
|
|
if (dp.to[i] != SQ_NONE)
|
|
added->push_back(make_index(perspective, dp.to[i], pc, ksq));
|
|
}
|
|
}
|
|
|
|
template class HalfKP<Side::kFriend>;
|
|
|
|
} // namespace Stockfish::Eval::NNUE::Features
|