pynbody/pynbody — pull request #157 by rokroskar (2014-04-24 22:59:31+00:00)
Title: fix for #156 -- support loading DM only files for gadgethdf

fixed a few things:

* check which particle types are actually present https://github.com/pynbody/pynbody/blob/gadget_hdf_fix/pynbody/gadgethdf.py#L107-L113

* fixed the parameter and unit decorators to fail gracefully if certain things aren't there
* recognize to use default units when no unit information is present and issue a warning (as per what is done for the tipsy format)

still needs fixing:

* in the file given to me by Brendan, it seems that the velocities array is not being read properly, i.e. `s['vel']` doesn't find the 'Velocity' array

need to check:

* does this break outputs with dm+stars+gas? I don't have one to test