message: fix compilation issue with parallel for collapse
diff: @@ -354,10 +354,11 @@ void convert_to_hybrid(std::shared_ptr<const OmpExecutor> exec,
  Array<IndexType> coo_row_ptrs_array(exec, num_rows);
  auto coo_row_ptrs = coo_row_ptrs_array.get_data();
  + auto ell_nnz_row = result->get_ell_num_stored_elements_per_row();
  + auto ell_stride = result->get_ell_stride();
  #pragma omp parallel for collapse(2)
  - for (size_type i = 0; i < result->get_ell_num_stored_elements_per_row();
  - i++) {
  - for (size_type j = 0; j < result->get_ell_stride(); j++) {
  + for (size_type i = 0; i < ell_nnz_row; i++) {
  + for (size_type j = 0; j < ell_stride; j++) {
  result->ell_val_at(j, i) = zero<ValueType>();
  result->ell_col_at(j, i) = 0;
  }
  