[Yt-dev] HaloProfiler Problems

Britton Smith brittonsmith at gmail.com
Sun Jan 25 15:40:16 PST 2009


I think I see what the problem is here.  The smallest bin for the profile is
0.021 and the maximum radius is 0.029, so even if 64 bins are requested, the
profiler is only going to have one bin or bins full of zeros.  From the
orginal error message, it looks like it only had one bin.  Since virial
quantities are calculated by interpolating between bins where the
overdensity crosses the critical overdensity, it needs at least 2 bins to do
anything.  I think the solution is to put a check in to see if the profile
only has one bin, and skip further operations on that halo.

As a side note, the first bin for CellVolume will always be zero, since the
radius of the bin is zero.  Maybe that should be changed.  Any thoughts on
that?

I can commit a fix to this that works as mentioned above.  Any objections to
this?

Thanks for finding that!

Britton

On Sun, Jan 25, 2009 at 4:27 PM, Stephen Skory <stephenskory at yahoo.com>wrote:

>
>
> ----- Original Message ----
> > From: Matthew Turk <matthewturk at gmail.com>
> > To: yt-dev at lists.spacepope.org
> > Sent: Sunday, January 25, 2009 3:22:09 PM
> > Subject: Re: [Yt-dev] HaloProfiler Problems
> >
> > OH!  And what's the radius of the halo, and how many cells does it get
> > if you make a sphere from the HOPGroup?  THAT is the key thing,
> > actually...
>
> When it calls this on the first problem halo:
>
> profile =
> lagos.BinnedProfile1D(sphere,self.haloProfilerParameters['n_bins'],"RadiusMpc",
>                        (4*self.pf.h.get_smallest_dx() * self.pf
> ['mpc']),halo['r_max'],
>                        log_space=True, lazy_reader=True)
>
>
> self.haloProfilerParameters['n_bins'] = 64
> (4*self.pf.h.get_smallest_dx() * self.pf['mpc']) = 0.021143
> halo['r_max'] = 0.029493
>
> _______________________________________________________
> sskory at physics.ucsd.edu           o__  Stephen Skory
> http://physics.ucsd.edu/~sskory/ <http://physics.ucsd.edu/%7Esskory/> _.>/
> _Graduate Student
> ________________________________(_)_\(_)_______________
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