[yt-users] merger tree crash

Cameron Hummels chummels at gmail.com
Tue Oct 29 06:19:46 PDT 2013


Hi Latif,

Thanks for the detailed information including the yt version and the output!

What you're experiencing here looks like normal behavior actually, at least
in my experience.  When the merger tree tracks halos back in time, it goes
from timestep output to earlier timestep output, looking for the halo at a
previous timestep which contains the largest number of the particles in the
current timestep.  Unfortunately, at early times, like z=30, very few halos
have actually formed because they just haven't had enough time for
gravitational collapse to take over.  Thus, the merger tree fails because
it cannot find a parent halo at that timestep.

However, it might be worthwhile for us to make the error message more
explanatory so that it's obvious what is happening.  I'll make an issue for
this to be corrected in the future.

Cameron


On Tue, Oct 29, 2013 at 4:12 AM, Latif <latifne at gmail.com> wrote:

> Hi all,
> I am running merger tree on Enzo simulations following the recipe given in
> YT documentation. YT crashes by producing the following error. I am using
> yt version "b118390aa42c".  Any ideas what is going on here?
>
> FOF CPU TIME: 2.408634 secs
> ========== Cycle 00009 (z=9.999997) ==========
> Parent halo = 0
> --> Most massive progenitor == Halo -1
> ========== Cycle 00008 (z=14.999989) ==========
> ========== Cycle 00007 (z=19.999992) ==========
> ========== Cycle 00006 (z=29.999961) ==========
> Traceback (most recent call last):
>   File "enzo.py", line 33, in <module>
>     mt.save_halo_evolution('halos.h5')
>   File
> "/home/uni05/mlatif/ytnew/yt-x86_64/src/yt-hg/yt/analysis_modules/halo_merger_tree/enzofof_merger_tree.py",
> line 507, in save_halo_evolution
>     halo_id = self.levels[cycle_fin][0].halo_id
> IndexError: list index out of range
>
> Thanks in advance,
> Cheers
> Latif
>
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>


-- 
Cameron Hummels
Postdoctoral Researcher
Steward Observatory
University of Arizona
http://chummels.org
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