[yt-users] Star Projections

Stephen Skory s at skory.us
Tue Dec 4 13:10:56 PST 2012


Hi Munier,

>   File
> "/share/home/01686/msalem/yt-x86_64/src/yt-hg/yt/data_objects/field_info_container.py",
> line 412, in __call__
>     raise NeedsDataField(doesnt_have)
> yt.data_objects.field_info_container.NeedsDataField: (['creation_time'])
>
>      Is anyone aware of what the issue may be? I'm wondering if enzo itself
> is not printing something yt needs here.

This last bit of your error message says what's going on - yt is
trying to access the 'creation_time' particle field and can't find it.
There are a few reasons for this - either the snapshot you're using
has no stars, has only a few stars in a few grids and yt isn't finding
it automatically, or perhaps the snapshot has a grid with no particles
at all. All are easy to test with this simple example script:

pf = load('snapshot')
all_fields = set(pf.h.derived_field_list + pf.h.field_list)

if 'creation_time' not in all_fields:
    print "creation_time is probably not in this simulation"

ct_yes = 0
ct_no = 0
for g in pf.h.grids:
    try:
        ct = g['creation_time']
        ct_yes+=1
    except:
        ct_no += 1

print "From %d grids, %d have stars, and %d have no particles." %
(ct_yes + ct_no, ct_yes, ct_no)

Can you run this script (modified for your situation) and report back, please?

Good luck!

--
Stephen Skory
s at skory.us
http://stephenskory.com/
510.621.3687 (google voice)



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