[yt-users] merger tree crash

[Latif]

Hi Cameron,
Thanks, You are very right.  Indeed, the problem was coming from the fact
that it could not parent halo at higher redshift (i.e., z= 40). It was
misleading to some other error which confused me.  It might be good to put
a check statement in the code that halofinder is unable to find parents or
some thing similar.
Cheers
Latif


On Tue, Oct 29, 2013 at 2:19 PM, Cameron Hummels <chummels at gmail.com> wrote:

> 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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