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PARALLELING COMPUTATION
Posted: 16 Jun 2021, 15:52
by Andrea_P
Good morning Community,
I want to run a simulation with more than one processor, but I don't know how to do it. I have Elmer on a Fedora machine. I appreciate any help.
Regards,
Andrea
Re: PARALLELING COMPUTATION
Posted: 16 Jun 2021, 17:54
by kevinarden
Do you run ElmerSolver for the GUI or a command line in general from a command line
You must first partition mesh to number of processors for example 4
ElmerGrid 2 2 Mymeshname -partdual -metiskway 4
then execute the mpi solver of the machine if it is openmpi then likely
mpirun -np 4 ElmerSolver_mpi
assuming the case.sif file is in the ELMERSOLER_STARTINFO file if not than
mpirun -np 4 ElmerSolver_mpi mycase.sif
If running from ElmerGUI go to run parallel settings and check parallel solver set number of processes, then set the commands in the window.
Re: PARALLELING COMPUTATION
Posted: 16 Jun 2021, 18:09
by Andrea_P
kevinarden wrote: ↑16 Jun 2021, 17:54
Do you run ElmerSolver for the GUI or a command line in general from a command line
You must first partition mesh to number of processors for example 4
ElmerGrid 2 2 Mymeshname -partdual -metiskway 4
then execute the mpi solver of the machine if it is openmpi then likely
mpirun -np 4 ElmerSolver_mpi
assuming the case.sif file is in the ELMERSOLER_STARTINFO file if not than
mpirun -np 4 ElmerSolver_mpi mycase.sif
If running from ElmerGUI go to run parallel settings and check parallel solver set number of processes, then set the commands in the window.
I am in the last case, so do I have to write something in the case.sif?
-Andrea
Re: PARALLELING COMPUTATION
Posted: 16 Jun 2021, 22:01
by raback
Hi
Usually sif file stays the same. There may be some features that do not work out of the box. It is good idea to verify that you get the same results in serial and parallel by comparing the results.
How many real cores do you have on your machine?
-Peter
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 01:31
by Andrea_P
raback wrote: ↑16 Jun 2021, 22:01
Hi
Usually sif file stays the same. There may be some features that do not work out of the box. It is good idea to verify that you get the same results in serial and parallel by comparing the results.
How many real cores do you have on your machine?
-Peter
I think 128, it is a cluster
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 12:01
by kevinarden
You go to run, parallel setting, check the box on hot select number of processes.
You will likely have to find the name of the mpi exectuable on the system, you can try the default, but it is probably different.
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 12:45
by Andrea_P
kevinarden wrote: ↑17 Jun 2021, 12:01
You go to run, parallel setting, check the box on hot select number of processes.
You will likely have to find the name of the mpi exectuable on the system, you can try the default, but it is probably different.
I have tried, but it does not work.
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 12:56
by kevinarden
Good news is that the mesh partition with ElmerGrid work
Problem is that last line in the output
Unable to start parallel solver
means that you do not have the right mpi executable name in executable field, either you have a different mpi solver installed on the system or there is no mpi solver on the system.
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 13:00
by Andrea_P
kevinarden wrote: ↑17 Jun 2021, 12:56
Good news is that the mesh partition with ElmerGrid work
Problem is that last line in the output
Unable to start parallel solver
means that you do not have the right mpi executable name in executable field, either you have a different mpi solver installed on the system or there is no mpi solver on the system.
How can I check? By the way, could I use this function of Elmer in windows?
Re: PARALLELING COMPUTATION
Posted: 17 Jun 2021, 14:45
by kevinarden
Yes it can be used in windows.
You could try mpiexec instead of mpirun, MPICH uses mpiexec.