[yt-users] Error loading data in ray

[Sam Geen]

Hi,

I'm trying to read data from a RAMSES output using a ray (c.f. 
http://yt-project.org/docs/dev/analyzing/generating_processed_data.html#line-queries-and-planar-integrals) 
- I basically call:

import yt.mods
pf = yt.mods.load("output_00007/info_00007.txt")
ray = pf.h.ray((0.5,0.5,0.5),(0,0,0))
ray["Density"] # <-- throws exception here

It works fine up until when I try to query the density, whereupon it 
throws a KeyError (ray.keys() is also empty). It seems to find all the 
fields fine when creating the ray object. Error log at the bottom of the 
e-mail.

I'm pretty sure I'm using the latest version of YT from the yt-3.0 
branch of the yt repository, but if I'm the only one getting this error 
I can double-check.

Anyone have any ideas? Failing that, if there's a better way to sample 
data along a line in YT, let me know.

Thanks!

Sam

---
In [5]: print ray["Density"]
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-5-dbeb4caf2ed1> in <module>()
----> 1 print ray["Density"]

/home/samgeen/.local/lib/python2.7/site-packages/yt-3.0dev-py2.7-linux-x86_64.egg/yt/data_objects/data_containers.pyc 
in __getitem__(self, key)
     189                 return self.field_data[f]
     190             else:
--> 191                 self.get_data(f)
     192         # Note that this is less succinct so that we can 
account for the case
     193         # when there are, for example, no elements in the object.

/home/samgeen/.local/lib/python2.7/site-packages/yt-3.0dev-py2.7-linux-x86_64.egg/yt/data_objects/data_containers.pyc 
in get_data(self, fields)
     573         # need to be generated.
     574         read_fluids, gen_fluids = 
self.hierarchy._read_fluid_fields(
--> 575                                         fluids, self, 
self._current_chunk)
     576         self.field_data.update(read_fluids)
     577

/home/samgeen/.local/lib/python2.7/site-packages/yt-3.0dev-py2.7-linux-x86_64.egg/yt/geometry/geometry_handler.pyc 
in _read_fluid_fields(self, fields, dobj, chunk)
     533             selector,
     534             fields_to_read,
--> 535             chunk_size)
     536         for field in fields_to_read:
     537             ftype, fname = field

/home/samgeen/.local/lib/python2.7/site-packages/yt-3.0dev-py2.7-linux-x86_64.egg/yt/frontends/ramses/io.pyc 
in _read_fluid_selection(self, chunks, selector, fields, size)
      47         d = {}
      48         for field in fields:
---> 49             d[field] = np.concatenate(tr.pop(field))
      50         return d
      51

KeyError: ('gas', 'Density')
---