Ok, thank you for your answer. I think this rankfile feature is very interesting to run some jobs like MPMD jobs or hybrid jobs (multithreaded or GPU for examples).Point taken. The basic premise Jeff and I are working on is to see if we could come up with a set of options that can cover most cases of job layouts. I am thinking jobs that are fairly uniform in layout (which I believe hybrid jobs can be) are easily supported. In the case of MPMD jobs I imagine one can conjure up a non-uniform layout that would be difficult, if not impossible, to define with some options.