Hi Zhouyang, The RestartFile stores the number of files, for example Nold, used for averaging. When re-running a simulation, new time snapshots are added to Nold * RestartFile and the number of files are also updated as Nold + Nnew. You can refer to this function for more details. SolverUtils::FilterFieldConvert::v_Initialise (https://doc.nektar.info/doxygen/latest/class_nektar_1_1_solver_utils_1_1_fil...) Cheers Ankang -- Research Associate Department of modern mechanics University of Science and Technology of China -----Original Messages----- From:"王舟阳" <wangzhouyang@buaa.edu.cn> Sent Time:2024-02-19 11:47:24 (Monday) To: nektar-users@imperial.ac.uk Cc: Subject: [Nektar-users] Question about restart file in Time-averaged fields filter | This email from wangzhouyang@buaa.edu.cn originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list to disable email stamping for this address. | Dear Nektar++ users and developers: Hi, everyone, I am sorry to disturb. My question is about the calculation of the "Time-averaged fields" in filters. One of the input options is: "RestartFile", how should I use this option correctly? For example: I have five checkpoints such as s_1.chk, s_2.chk, s_3.chk, s_4.chk, s_5.chk, and their time-mean field s_avg.fld, besides the final output file s.fld. Then, I want to continue my simulation, so I write s.fld as the initial condition function (in <FUNCTION NAME="InitialConditions">). At this time, I hope to use s_avg.fld as the restart file (in <PARAM NAME="RestartFile">s_avg.fld</PARAM>) of the time-average field filter to reduce the time consumption of the entire simulation process by utilizing all the results obtained. I would like to ask users and developers whether I understand RestartFile option correctly (might it be used to take the original time-average field as the first snapshot in my process)? How could I correctly fill the filter section of the xml document. Thank you very much and look forward to your reply. Best Regards, Wang Zhouyang