Troubleshooting NekRS at Runtime
This page collects some common issues encountered when running NekRS models. Generally, if you are encountering issues it is a good idea to clear the cache directory so that you're absolutely sure there aren't old case build files lingering around that are causing conflicts. Try the following first:
and then re-run your case. If the issue persists, check out these other potential causes.
MPI_Abort
If a NekRS-wrapped case immediately fails with just an MPI Abort, like this:
this usually means that you have an error in your NekRS case files (like an invalid parameter). Unfortunately, NekRS does not always propagate these errors upwards to the console, so it's impossible to diagnose what actually went wrong if you only see an MPI Abort. You can figure out what the error is by instead just running the nrsmpi
executable, like
which will display the root cause of the MPI Abort. We have an issue to resolve this in the future.
Insufficient Memory
If you encounter an error like the following
this means that you have likely run out of memory. Please increase the number of nodes. In some cases, you might need to delete the .cache
directory for the new pre-compilation to occur correctly.
Threading
NekRS does not support threading. On some systems, you might see an error like
This error can usually be addressed by explicitly telling NekRS to use just 1 OpenMC thread, with export OMP_NUM_THREADS=1
.