Moved the nnue folder.

src/nnue/features/k.cpp

@@ -0,0 +1,49 @@
+//Definition of input feature quantity K of NNUE evaluation function
+
+#if defined(EVAL_NNUE)
+
+#include "k.h"
+#include "index_list.h"
+
+namespace Eval {
+
+namespace NNUE {
+
+namespace Features {
+
+// Get a list of indices with a value of 1 among the features
+void K::AppendActiveIndices(
+    const Position& pos, Color perspective, IndexList* active) {
+  // do nothing if array size is small to avoid compiler warning
+  if (RawFeatures::kMaxActiveDimensions < kMaxActiveDimensions) return;
+
+  const BonaPiece* pieces = (perspective == BLACK) ?
+      pos.eval_list()->piece_list_fb() :
+      pos.eval_list()->piece_list_fw();
+  assert(pieces[PIECE_NUMBER_BKING] != BONA_PIECE_ZERO);
+  assert(pieces[PIECE_NUMBER_WKING] != BONA_PIECE_ZERO);
+  for (PieceNumber i = PIECE_NUMBER_KING; i < PIECE_NUMBER_NB; ++i) {
+    active->push_back(pieces[i] - fe_end);
+  }
+}
+
+// Get a list of indices whose values ​​have changed from the previous one in the feature quantity
+void K::AppendChangedIndices(
+    const Position& pos, Color perspective,
+    IndexList* removed, IndexList* added) {
+  const auto& dp = pos.state()->dirtyPiece;
+  if (dp.pieceNo[0] >= PIECE_NUMBER_KING) {
+    removed->push_back(
+        dp.changed_piece[0].old_piece.from[perspective] - fe_end);
+    added->push_back(
+        dp.changed_piece[0].new_piece.from[perspective] - fe_end);
+  }
+}
+
+}  // namespace Features
+
+}  // namespace NNUE
+
+}  // namespace Eval
+
+#endif  // defined(EVAL_NNUE)