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59 lines
1.5 KiB
C++
59 lines
1.5 KiB
C++
//Definition of input feature quantity K of NNUE evaluation function
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#if defined(EVAL_NNUE)
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#include "k.h"
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#include "index_list.h"
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namespace Eval {
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namespace NNUE {
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namespace Features {
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// Orient a square according to perspective (rotates by 180 for black)
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inline Square orient(Color perspective, Square s) {
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return Square(int(s) ^ (bool(perspective) * 63));
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}
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// Index of a feature for a given king position.
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IndexType K::MakeIndex(Color perspective, Square s, Color king_color) {
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return IndexType(orient(perspective, s) + bool(perspective ^ king_color) * 64);
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}
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// Get a list of indices with a value of 1 among the features
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void K::AppendActiveIndices(
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const Position& pos, Color perspective, IndexList* active) {
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for (auto color : Colors) {
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active->push_back(MakeIndex(perspective, pos.square<KING>(color), color));
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}
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}
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// Get a list of indices whose values have changed from the previous one in the feature quantity
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void K::AppendChangedIndices(
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const Position& pos, Color perspective,
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IndexList* removed, IndexList* added) {
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const auto& dp = pos.state()->dirtyPiece;
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Color king_color;
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if (dp.piece[0] == Piece::W_KING) {
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king_color = WHITE;
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}
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else if (dp.piece[0] == Piece::B_KING) {
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king_color = BLACK;
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}
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else {
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return;
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}
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removed->push_back(MakeIndex(perspective, dp.from[0], king_color));
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added->push_back(MakeIndex(perspective, dp.to[0], king_color));
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}
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} // namespace Features
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} // namespace NNUE
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} // namespace Eval
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#endif // defined(EVAL_NNUE)
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