[yt-dev] Issue #1166: YTFieldNotFound for angular momentum (yt_analysis/yt)

[Joyce Lee]

New issue 1166: YTFieldNotFound for angular momentum
https://bitbucket.org/yt_analysis/yt/issues/1166/ytfieldnotfound-for-angular-momentum

Joyce Lee:

I'm working with 3D simulation data (ORION) to find angular momentum vector. 

http://use.yt/upload/f1926f08
http://use.yt/upload/272030ab
http://use.yt/upload/5e496e7c

I run the following:

```
#!python

import yt
file = "data.0200.3d.hdf5"
ds = yt.load(file)
sp = ds.sphere("center", (0.1, 'pc'))

L = sp.quantities.angular_momentum_vector()
```


and get the following traceback

```
#!python

/Users/joycelee/yt-x86_64/src/yt-hg/yt/data_objects/derived_quantities.pyc in __call__(self, *args, **kwargs)
     66         storage = {}
     67         for sto, ds in parallel_objects(chunks, -1, storage = storage):
---> 68             sto.result = self.process_chunk(ds, *args, **kwargs)
     69         # Now storage will have everything, and will be done via pickling, so
     70         # the units will be preserved.  (Credit to Nathan for this

/Users/joycelee/yt-x86_64/src/yt-hg/yt/data_objects/derived_quantities.pyc in process_chunk(self, data, use_gas, use_particles)
    458             rvals.extend([(data["all", "particle_specific_angular_momentum_%s" % axis] *
    459                            data["all", "particle_mass"]).sum(dtype=np.float64) \
--> 460                           for axis in "xyz"])
    461             rvals.append(data["all", "particle_mass"].sum(dtype=np.float64))
    462         return rvals

/Users/joycelee/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in __getitem__(self, key)
    244         Returns a single field.  Will add if necessary.
    245         """
--> 246         f = self._determine_fields([key])[0]
    247         if f not in self.field_data and key not in self.field_data:
    248             if f in self._container_fields:

/Users/joycelee/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in _determine_fields(self, fields)
    513                     raise YTFieldNotParseable(field)
    514                 ftype, fname = field
--> 515                 finfo = self.ds._get_field_info(ftype, fname)
    516             else:
    517                 fname = field

/Users/joycelee/yt-x86_64/src/yt-hg/yt/data_objects/static_output.pyc in _get_field_info(self, ftype, fname)
    541                     self._last_finfo = self.field_info[(ftype, fname)]
    542                     return self._last_finfo
--> 543         raise YTFieldNotFound((ftype, fname), self)
    544 
    545     def _setup_classes(self):

YTFieldNotFound: Could not find field '('all', 'particle_specific_angular_momentum_x')' in data.0200.3d.hdf5.
```