Hi Nicola, In the check point file, the expansion coefficients of the flow fields are stored based on the number of modes and the expansion type defined in the session file. You are correct that the FieldConvert reads the coefficients data in the checkpoint file and then evaluates the physics values at the equispaced points. This evaluation is exact. I don't think you need to specify the number of modes or expansion type in this process. I am not quite sure what causes the bad_alloc issue. Given that you are using quite a large value 128 for -n, could it be possible that your machine runs out of memory? Best Regards Ankang Gao -- Research Associate Department of Modern Mechanics University of Science and Technology of China -----Original Messages----- From:"Nico Clinco" <nicoclinco@gmail.com> Sent Time:2024-01-29 15:44:39 (Monday) To: nektar-users@imperial.ac.uk Cc: Subject: [Nektar-users] FieldConvert: problem in specifying the number of equispaced points | This email from nicoclinco@gmail.com 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 All, i'm trying to use the FieldConvert utility with the option "-n" to specify the number of points for equispaced interpolation in each direction. I have attached in the pic below what happens if i try the command (i receive a bad_alloc error). I think that FieldConvert use the modes specified in the session file to interpolate at a set of equispaced points. I was wondering if it is possible to specify the number of modes and also the types for the interpolation. Thanks in advance. Nicola