[yt-users] ARTIO and find_field_value_at_point

[Nathan Goldbaum]

The code is still there, but it is not hooked up to anything.  In
particular the grid hierarchy object no longer inherits from the
ObjectFindingMixin.

I think It should be possible to implement a generic version of
find_field_value_at_point that uses the chunking system.  If that's not
true, I think different Index subclass (i.e. the GridIndex - which used to
be the GridHierarchy - the OctIndex, etc.) should implement it and then
delegate to a method that is attached to the `Dataset` class.  For example,
the find_min and find_max methods which used to be defined using
ObjectFindingMixin are now implemented in a chunk-aware method using
derived quantities.

I think this is totally doable, it's just that no one has actually sat down
and done it yet.  It would be nice if we could get
find_field_value_at_point implemented before the release of yt 3.0 since
it's a useful bit of functionality.

-Nathan


On Wed, May 21, 2014 at 2:48 PM, Douglas Harvey Rudd <drudd at uchicago.edu>wrote:

>  Hi Nathan,
>
>  When you say it's not functional, is it an issue of
> find_field_value_at_point not being implemented for Oct (or ART oct)
> geometry?
>
>  Douglas Rudd
> Scientific Computing Consultant
> Research Computing Center
>  drudd at uchicago.edu
>
>
>
>  On May 21, 2014, at 2:05 PM, Nathan Goldbaum <nathan12343 at gmail.com>
> wrote:
>
>  Hi Alexander,
>
>  You're right, that functionality is currently not functional.  The error
> message could certainly be improved - but basically it is trying to find
> the attribute find_field_value_at_point attached to the `Dataset` object
> and is not successful.  Also, it's worth noting that `pf.h` is the same
> thing as just `pf` in the current version of yt-3.0.  `pf.h` exists only
> for compatibility with legacy scripts and should be avoided in new scripts.
>
>  In yt 2.x, this functionality was provided via the ObjectFindingMixin
> class, which the GridHierarchy inherited from. Since the algorithm
> implemented by the find_field_value_at_point only worked for grid datasets,
> it has been disabled in yt-3.0. I think the plan is to reimplement it using
> the new chunking system but no one has done so yet.
>
>  See this issue:
> https://bitbucket.org/yt_analysis/yt/issue/499/missing-hierarchy-functions
>
>  Cheers,
>
>  Nathan
>
>
>
> On Wed, May 21, 2014 at 11:42 AM, Alexander A. Kaurov <akaurov at gmail.com>wrote:
>
>> Hi all,
>>
>> I'm trying to access field value in a given point in ARTIO file (sample
>> data file: sizmbhloz-clref04SNth-rs9_a0.9011
>> ​). ​The function '
>>  ​
>> find_field_value_at_point
>> ​' seems to be not working. May be I'm using it wrong?​
>>
>>  ​Here is the code:
>>
>>  from yt.mods import *
>> ​
>>
>> pf=load('test-data/sizmbhloz-clref04SNth-rs9_a0.9011/sizmbhloz-clref04SNth-rs9_a0.9011.art')
>> pf.h.
>> ​​
>> find_field_value_at_point(('artio', 'HVAR_GAS_DENSITY'),[0.1,0.1,0.1])
>>
>> ​And the error:
>>
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in <module>
>>   File
>> "/lustre/kaurov/anaconda/lib/python2.7/site-packages/yt-3.0dev-py2.7-linux-x86_64.egg/yt/data_objects/static_output.py",
>> line 84, in __getattr__
>>     raise AttributeError
>> AttributeError
>>
>>  ​Thanks!
>>
>>  Sasha​
>>
>>
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>>
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