I think you could also do something similar with a 1D profile, though it isn't quite as easy to dial in an exact limit:
where you define the whole box as the region you care about and then do:
# Get the whole box
reg = pf.h.all_data()
# Make the profile
metal_mass = pc.add_profile_object(reg, ["Metallicity", "CellMass"])
# Get some easy pointers to the profile data
bins = metal_mass.data._bins
mass = metal_mass.data["CellMass"]
# Now get total mass with Metallicity above a 1.0e-4 by getting the number of
mass_frac = mass[bins>1.0e-4].sum()/mass.sum()
That should give you something close to what you'd want. You may want to increase the number of xbins if you want higher accuracy answer. Finally, I'll just make a quick note that the profile creation can be done in parallel as long as lazy_reader=True, which it is by default.
There may be other ways to do this as well, but this is what I'd probably do.
On Thu, Aug 26, 2010 at 7:00 AM, John Wise <email@example.com>
I wanted to calculate volume filling fractions and mass fractions of gas that met some criteria. Specifically, the fractions that have a certain metallicity. The _Action routine looked promising, but I couldn't figure out how to use it. I remember there was some talk about filters on the list, but I searched and found that it concerned the halo finder.
I might have reinvented the wheel, but this is how I did it.
It's basically _TotalQuantity with a filter. Also I wanted it to accept multiple limits to avoid re-reading the data for every filter.
Was there an easier way to do this?
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Samuel W. Skillman
DOE Computational Science Graduate Fellow
Center for Astrophysics and Space Astronomy
University of Colorado at Boulder