Function MakeSparseTensorIndexCOO

cpp/src/arrow/ipc/metadata_internal.cc:1069–1094

}

Status MakeSparseTensorIndexCOO(FBB& fbb, const SparseCOOIndex& sparse_index,
                                const std::vector<BufferMetadata>& buffers,
                                flatbuf::SparseTensorIndex* fb_sparse_index_type,
                                Offset* fb_sparse_index, size_t* num_buffers) {
  *fb_sparse_index_type =
      flatbuf::SparseTensorIndex::SparseTensorIndex_SparseTensorIndexCOO;

  // We assume that the value type of indices tensor is an integer.
  const auto& index_value_type =
      checked_cast<const IntegerType&>(*sparse_index.indices()->type());
  auto indices_type_offset =
      flatbuf::CreateInt(fbb, index_value_type.bit_width(), index_value_type.is_signed());

  auto fb_strides = fbb.CreateVector(sparse_index.indices()->strides().data(),
                                     sparse_index.indices()->strides().size());

  const BufferMetadata& indices_metadata = buffers[0];
  flatbuf::Buffer indices(indices_metadata.offset, indices_metadata.length);

  *fb_sparse_index =
      flatbuf::CreateSparseTensorIndexCOO(fbb, indices_type_offset, fb_strides, &indices,
                                          sparse_index.is_canonical())
          .Union();
  *num_buffers = 1;
  return Status::OK();
}

template <typename SparseIndexType>
struct SparseMatrixCompressedAxis {};