[OMPI users] How to override default hostfile to specify host

[Saurabh T]

Hi,

If I use "orterun -H <machine>" and <machine> does not belong in the default 
hostfile ("etc/openmpi-default-hostfile"), openmpi gives an error. Is there an 
easy way to get the aforementioned command to work without specifying a 
different hostfile with <machine> in it? Thank you.