[SarahLee]

Dear all,

We are having trouble running OpenFOAM 3+ cases in parallel. When running:
mpiexec -np 2 buoyantboussinesqsimplefoam.exe -parallel (on Windows 7 and 10), we get:

--> FOAM FATAL ERROR:
bool IPstream::init(int& argc, char**& argv) : attempt to run parallel on 1 processor

This happens in a newly set up case, but also in old cases which were running fine with OpenFOAM 3+ about a month ago. So we don't believe the case is set up or decomposed incorrectly.

We have two theories:
- something got messed up by a windows update
- we have since then installed FDS, and this messed up the mpiexec for openFOAM

I am by far no IT-expert, so I don't know it these are even viable theories?

Any ideas on what to read or what to try?

I found an old thread that may help, but don't know how to translate the bashrc to Windows:
OF 2.0.1 parallel running problems

Thanks!

Sarah

[SarahLee]

Dear all

As an answer to my own question, we found the problem:
Using "where mpiexec" in the cmd-window, there were indeed two different mpiexec.exe's installed: FDS and Microsoft HPC Pack. The one from FDS has priority, but OpenFOAM needs the other one.

Solution: run the mpiexec with the full path.
There is probably a more elegant solution, but this one works. :-)

Cheers,

Sarah

[floquation]

Originally Posted by SarahLee

There is probably a more elegant solution, but this one works. :-)

You probably have defined an alias to load openfoam in your bashrc file. Within that alias, you could give the mpiexec you need preference by moving its path up in your $PATH environmental variable:

alias of240="blabla && PATH='path-to-directory-containing-the-desired-mpiexec:'$PATH"

The $PATH variable is searched top-down until your command is found. If your command appears multiple times in the list, only the first one is found/taken. Therefore, moving its path to the top of the list will ensure that it will be chosen.
Disadvantage: if other duplicate commands appear in those two directories (the two containing the two different mpiexec's), preference for a different command might suddenly be given to the one you didn't want, but this scenario is not very likely.