[ghastbug]

I have installed the OpenFOAM mingw build for windows. And I have been trying to run the PitzDaily case in parallel. It does not work properly



My decomposeParDict is set with 6 cores, scotch, and coeff( 3,2,1). It works fine. So when I run decomposePar, it works


However, when I run mpirun -nc 6 simpleFOAM -parallel, I get an error:
"bash: mpirun: could not find the command" EDIT: it is mpirun -np 6 simpleFoam -parallel, the previous command is a typo, thx Yann


I also tried the foamjob version: foamJob -s -parallel simpleFoam, and I get the error: 'mpirun' not found


Idea: I think I don't have openMPI installed. I mean, I installed MSMPI with openFOAM by default, but they are different things... I think, yeah.



Idea 2: I ran :mpiexec -n 6 simpleFoam. Because I found in How to ues MSMPI in CONVERGE? that msmpi can be run with mpiexec. But it is slower than running simpleFoam alone.
simpleFoam: clocktime = 6 seconds
mpiexec- -n 6 simpleFoam: clocktime = 10 seconds
Actually, running mpiexec simpleFoam takes 26 seconds. So the problem is that mpiexec is slower than the default openFOAM mpi stuff

Idea3: if I run the airfoil2D tutorial case with ./Allrun, it works, with parallel processing included. However, I do not even know in what programming language the Allrun file is writtten. I mean, probably C, but there are lines of code I don't understand


Questions:


1-What is the correct command to run solvers in parallel with mingw?
2- Do I have to install openmpi? I think there is no windows version
3- why is it slower when I run mpiexec ? what is the difference between writing simpleFoam and mpiexdc simpleFoam

[Yann]

Hi,

Originally Posted by ghastbug

However, when I run mpirun -nc 6 simpleFOAM -parallel, I get an error:

"bash: mpirun: could not find the command"

I'm not sure this is related to your error and I'm also not sure if you made some typos when writing your post but just to be sure, this is the exact command you should type:

mpirun -np 6 simpleFoam -parallel

Originally Posted by ghastbug

Idea 2: I ran :mpiexec -n 6 simpleFoam. Because I found in How to ues MSMPI in CONVERGE? that msmpi can be run with mpiexec. But it is slower than running simpleFoam alone.
simpleFoam: clocktime = 6 seconds
mpiexec- -n 6 simpleFoam: clocktime = 10 seconds
Actually, running mpiexec simpleFoam takes 26 seconds. So the problem is that mpiexec is slower than the default openFOAM mpi stuff

The "-parallel" option is missing. If this is not a typo it means you are running 6 instances of simpleFoam in serial, and this is why it's longer. The correct command should be:

mpiexec -n 6 simpleFoam -parallel

Originally Posted by ghastbug

Idea3: if I run the airfoil2D tutorial case with ./Allrun, it works, with parallel processing included. However, I do not even know in what programming language the Allrun file is writtten. I mean, probably C, but there are lines of code I don't understand

Allrun files are written in shell and it uses RunFunctions which are functions defined in OpenFOAM (for instance, runApplication and runParallel are RunFunctions)

Not sure this will solve your openMPI issues but I hope at least it will give you some hints.
Yann

[ghastbug]

1- mpirun -nc 6 simpleFOAM -parallel is a typo, I'm adding a note to the OP


2- mpiexe -n 6 simpleFoam -parallel : oooh, beautiful, it works, thx.


3- shell files with runfunctions: exactly what I asked, thx. Now I can get some introductory knowledge on shell scripts from google and check where the runfunctions are located in openfoam