[Yt-dev] RMS mass overdensity method

[Matthew Turk]

>> Do you have ideas of what I should try next? Is there anywhere I can put some prints that would help us debug this? Should I switch tatics and instead extract the particle data out and use a KDTree?

Hi Stephen, sorry to reply to my own email, but on second thought I
wonder if maybe the variable over_density could be the problem.  I'd
suggest you try removing all interaction with it; alternatively, you
could instead make it a single float that gets updated, rather than a
list that goes to array that goes to float.  I am slightly concerned
that is where the wonkiness could come from.  Also try removing your
calls to the _mpi_* methods.  Also, you do see that you re-assign
self.samples during the call to sigma.__init__, yeah?  That could be a
problem.

-Matt