Hi Ehsan, The optimization is likely to be problem and architecture dependent. Normally, Nektar++ automatically produce an optimization file *.opt. You should be able to see it. If you want to examine the influence of optimization on computational time, I guess you can manually set IMPTYPE to “NoCollection”. Best, Jacques From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> On Behalf Of Ehsan Asgari Sent: Wednesday, August 9, 2023 3:23 PM To: Isaac Rosin <isaac.rosin1@ucalgary.ca> Cc: Maziyar Hassanpour <maziyar.hassanpour@ucalgary.ca>; nektar-users@imperial.ac.uk Subject: Re: [Nektar-users] Optimisation Issues Hi Isaac I am doing a simulation on a similar configuration, a wall-mounted cylinder with Re=750. It's actually the first time I read about the optimization technique to speed up the run. Could you let me know if it had a significant influence? Kind regards syavash On Wed, Aug 9, 2023 at 4:38 AM Isaac Rosin <isaac.rosin1@ucalgary.ca<mailto:isaac.rosin1@ucalgary.ca>> wrote: This email from isaac.rosin1@ucalgary.ca<mailto:isaac.rosin1@ucalgary.ca> 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<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Hello Nektar Community, I am running a full 3D DNS simulation at Re=400 of a flow past a rectangular prism using the incompressible solver. This flow is laminar but 3D effects are present. I am using a structured mesh generated using gmsh with a p order of 4 which comes to roughly 2.6 million degrees of freedom. A colleague is able to run a similar but slightly more complex DNS simulation at Re=3900 on 1/8 the number of processors and he still obtains results much faster. All signs indicate I should be able to use far fewer resources than I currently am, but neither of us can figure out how to optimise further than I already have. I followed the optimisation section of the Nektar user guide, tweaked my mesh several times, changed the time step size, etc., but all of these adjustments showed marginal improvements at best. I would be very grateful if anyone has any suggestions. I am providing my case files here: https://drive.google.com/drive/folders/1iT0GvZgE0MyfmjNe1GYMlAKJp-8fh57X?usp... the slurm file called P4.sh has the script I normally use on clusters. I look forward to hearing from you! All the best, Isaac _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users