Licallo/Troubleshooting.md

@@ -23,3 +23,28 @@ You need to remove the obsolete commands from your login resource files.
  * If that fail, the following command might help finding those files: `egrep '\bmodule\b' .??*`. 
 
 Then, setup your environment according to the [Software Environment](Licallo/Software Environment) page.
+
+## MPI
+### I get an error in `PMPI_Init` with module **intel-gnu8-runtime/19.0.5.281** and **impi**
+
+**Symptom**
+
+If you are using `mpirun/mpiexec` in that context, the PMI2 library comes in the way and causes problem.
+
+The error message will look like:
+```
+Abort(567055) on node 0 (rank 0 in comm 0): Fatal error in PMPI_Init: Other MPI error, error stack:
+MPIR_Init_thread(703):
+MPID_Init(739).......: PMI_Init returned -1
+
+```
+
+**Solution**
+
+In your script, before launching your code, unset **I_MPI_PMI_LIBRARY**:
+```
+...
+unset I_MPI_PMI_LIBRARY
+# Run the code, could use mpiexec                                                                                                                                                                  
+mpirun -n $SLURM_NTASKS ./dice
+```
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