Hello Praveer,
glad to see that you could make it work in the end.
Yours, Roland
Dear Dr. Roland,
Thank you for your detailed response. I really appreciate the time and thought you must've put into it.
I have followed your suggestion of removing the current Cactus build and compiling it again but received yet another error. The problem seems to be a mixup of multiple MPI implementations, just as you had suggested. I couldn't finesse my way out of it, so I re-installed Ubuntu instead(deleting everything in the process) and began from scratch. I installed only those packages mentioned on the Jupyter tutorial and the code compiled successfully this time.
Thank you once again for your helpful advice.
Regards, Praveer Krishna
On Fri, Mar 27, 2020 at 8:42 PM Roland Haas rhaas@illinois.edu wrote:
Hello Praveer Krishna,
since mpirun was not found initially it would seem that you had not MPI stack installed when compiling Cactus.
Cactus is best used with an MPI stack installed beforehand. The new user tutorial
https://nbviewer.jupyter.org/github/nds-org/jupyter-et/blob/master/CactusTut...
contains instructions on how to install a set up packages that simplify building Cactus, including MPI. Did you follow those instructions or started from a vanilla, freshly installed OS? Also, what OS are you using (OSX, Linux, Linux-Subsystem-on-Windows)?
The easiest way to get a working copy of Cactus, if you did not install an MPI stack before compiling Cactus, is:
- install an MPI stack (OpenMPI is fine)
- remove the current Cactus build using "rm -rf configs/sim"
- build once more
The solution above is the suggested solution.
If you would like to avoid recompiling (and risk triggering other issues instead), here's an alternative: When it detected that no MPI stack was installed then Cactus built its own copy of OpenMPI. It will have copied "mpirun" to "exe/sim/mpirun" and you can use that by making sure that the full path to the directory "exe/sim" appears in your PATH before you start the simulation. Using an mpirun from a different MPI stack than the one used to compile Cactus is what gives the error that Erik descibes in the email you found.
Yours, Roland
Dear ET Users,
I'm a beginner attempting to follow the Jupyter tutorial for new users. I have been able to successfully run the helloworld.par and tov_ET.par
files
with procs set to 1 but I'm having issues when I try to use multiple processors on my laptop. I initially got this error https://imgur.com/a/cuLLp79 saying "mpirun: not found", following which I installed Open MPI on my system. The error persisted, so I removed Open MPI and installed mpich instead. This seemingly fixed the issue, but I received another error https://imgur.com/gdXSqCj saying "CACTUS_NUM_PROCS is set to 4 but
there
are 1 MPI processes"
I found one <
https://www.mail-archive.com/search?l=users@einsteintoolkit.org&q=subjec...
or two https://www.mail-archive.com/users@einsteintoolkit.org/msg01591.html previous queries regarding this exact error, but the suggestions have not worked for me so far. Having never worked with MPI before, I am not sure what else I should try.
I'd be grateful for a few words of advice on this issue from anyone in
the
community. Thank you in advance for your time.
Regards, Praveer Krishna
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