Merge pull request #6527 from uiuc-hpc/fix-lci-doc

Improve the LCI parcelport documentation

docs/sphinx/manual/using_the_lci_parcelport.rst

@@ -89,14 +89,19 @@ Run |hpx| with the LCI parcelport
 =================================
 
 We use the same mechanisms as MPI to launch LCI, so you can use the same way you run MPI parcelport to run LCI
-parcelport. Typically, it would be ``hpxrun``, ``mpirun``, or ``srun``.
+parcelport. Typically, it would be ``hpxrun.py``, ``mpirun``, or ``srun``.
 
-If you are using ``hpxrun.py``, just pass ``--parcelport lci`` to the scripts.
+``hpxrun.py`` serves as a wrapper for ``mpirun`` and ``srun``.
+If you are using ``hpxrun.py``, pass ``-p lci`` to the scripts. You also need to pass either ``-r mpi`` or
+``-r srun`` to select the correct run wrapper according to the platform.
 
 If you are using ``mpirun`` or ``srun``, you can just pass
 ``--hpx:ini=hpx.parcel.lci.priority=1000``, ``--hpx:ini=hpx.parcel.lci.enable=1``, and
 ``--hpx:ini=hpx.parcel.bootstrap=lci`` to the |hpx| applications.
 
+The ``hpxrun.py`` argument ``-r none`` (the default option for the run wrapper) and its corresponding |hpx| arguments
+``--hpx:hpx`` and ``--hpx:agas`` do not work for the MPI or the LCI parcelport.
+
 .. _tune_lci_pp:
 
 Performance tuning of the LCI parcelport