Hi Syavash, Thank you for reaching out! 1. At the moment it is not possible to over-write the output fields that already written. However, it is intended to add this functionality in future versions. 2. Very Briefly: “MODIFIED” corresponds to modified Legendre polynomials (modal basis functions), while “GLL_LAGRANGE” corresponds to Lagrange polynomials (nodal basis functions) to approximate the pressure and the velocity fields that you are solving for. Each of these has a different formulation and implementation inside nektar++. If you are interested in knowing more about their implementation, you can look in chapter 2 of this book: https://academic.oup.com/book/7538 Kind regards, Alexandra From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> On Behalf Of Ehsan Asgari Sent: 07 March 2023 14:39 To: Nektar-users@imperial.ac.uk Subject: [Nektar-users] (no subject) This email from <mailto:eh.asgari@gmail.com> eh.asgari@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 <https://spam.ic.ac.uk/SpamConsole/Senders.aspx> safe senders list to disable email stamping for this address. Hi Everyone, I had two questions: 1-Is it possible to specify the output field overwrite using a parameter? For example, keeping only the last two time fields. I searched through the user-guide but couldn't find it. 2-What is the difference between "MODIFIED" and "GLL_LAGRANGE" under TYPE in the incompressible solver? I appreciate your kind responses. syavash