Hi everyone,
I have been searching on the internet and the forum to understand how I can setup an MFIX-DEM simulation from scratch with parallel runs. I have not seen an option on the GUI for partitioning options or number of processes to run. I saw a post and some replies that were concluding it is possible through Linux. Can you please indicate the steps necessary to run a case on parallel from scratch?
Thank you so much.
Hi Mahdi -
There are two forms of parallelism supported in MFiX: SMP (Shared Memory Parallel) which uses multiple CPUs on a single host, and DMP (Distributed Multiprocessing) which uses multiple hosts on a network (cluster). SMP is supported on Windows and Linux, DMP is Linux-only. Which of these are you interested in?
Hi Charles!
Thank you for your reply. I am starting to experiment MFIX-DEM for laminar flows on my computer first, which has 48 processor. Then I guess SMP will work for me for the moment. I have installed MFIX on Linux.
Thanks.
SMP is fairly straighforward, but you will need to compile the solver with SMP support. In the “Build solver” popup (wrench icon), make sure the SMP option is enabled:
Then when you run the job, you should be able to select up to 48 threads.
You may find it interesting to watch top in a terminal to see what’s going on. (Also very interesting is perf top if you have it installed).
Let us know how it goes!
– Charles
Thank you so much again Charles. Is there any tutorial that shows step by step simulation of a case by building the solver? There is an [advanced tutorials] (3.11. Advanced Tutorials — MFiX 22.1 documentation) section that looks to contain such examples of reacting flows which need solver building, but they are not active.
Thank you.
There’s this section of the manual: 5.1. Building Custom Interactive Solver — MFiX 22.1 documentation
Building the solver in the GUI is really just a few mouse-clicks, note that you don’t have to modify code, just enable SMP.
Are you having trouble with the build process? If so, what problem are you having?
– Charles
Oh no, I have not tried yet. I was just wondering the order of steps. So, it is like that you design the geometry, mesh, flow and solid properties, and the turbulent models so on… and then you click on the “build solver” right?
If you are not using UDFs (user-defined functions, i.e. writing your own custom Fortran code) then building the solver is really orthogonal to setting up the model. You can click the little wrench icon any time.
Thank you again for your response.
Hi Charles,
I had MFIX to build the solver using SMP, and then I tried to run it in parallel, and I received this message in the attached picture. Can you please have a look and give me a solution? Thank you so much.
Can it be because the directory path should not have any space between in the folder name?
Yes, it looks like that’s exactly what’s wrong. Try renaming the directory.
– Charles
Thanks again for your comment.
