ns3-三维数据如何记录

FileHelper fileHelper;

// Configure the file to be written.
fileHelper.ConfigureFile ("echo-distributed-simulaton",
                          FileAggregator::FORMATTED);

// Set the labels for this formatted output file.
fileHelper.Set3dFormat ("Time (Seconds) = %.3f\t"
                        "Packt byte of sending = %.0f\t"
                        "Packt byte of receiving = %.0f");

// Write the values generated by the probe.  The path that we
// provide helps to disambiguate the source of the trace.
fileHelper.WriteProbe ("ns3::Ipv4PacketProbe",
                       "/NodeList/*/$ns3::Ipv4L3Protocol/Tx",
                       "OutputBytes");
fileHelper.WriteProbe ("ns3::Ipv4PacketProbe",
                       "/NodeList/*/$ns3::Ipv4L3Protocol/Rx",
                       "OutputBytes");

这样子出来的txt总是写不进去东西 麻烦各位帮我看看