Remove useless group and part attributes

src/output/VTKWriter.cpp

@@ -523,10 +523,9 @@ VTKWriter::_write(const std::shared_ptr<const MeshType>& mesh,
       sout << m_base_filename;
       sout << '.' << std::setfill('0') << std::setw(4) << i_time << ".pvtu";
 
-      fout << "<DataSet timestep=\"" << m_saved_times[i_time] << "\" "
-           << "file=\"" << sout.str() << "\"/>\n";
+      fout << "<DataSet timestep=\"" << m_saved_times[i_time] << "\" file=\"" << sout.str() << "\"/>\n";
     }
-    fout << "<DataSet timestep=\"" << time << "\" group=\"\" part=\"0\" file=\"" << _getFilenamePVTU() << "\"/>\n";
+    fout << "<DataSet timestep=\"" << time << "\" file=\"" << _getFilenamePVTU() << "\"/>\n";
 
     fout << "</Collection>\n";
     fout << "</VTKFile>\n";