[yt-dev] [yt_analysis/yt] cut_region doesn't work in 3.0 (issue #552)

[Nathan Goldbaum]

New issue 552: cut_region doesn't work in 3.0
https://bitbucket.org/yt_analysis/yt/issue/552/cut_region-doesnt-work-in-30

Nathan Goldbaum:

It seems that subselecting on data objects using field cuts hasn't been implemented in 3.0.


```
#!python

from yt.mods import *

pf = load('DD0000/DD0000')
dd = pf.h.all_data()
lt = dd.cut_region("grid['Temperature'] < 1e5")
lt['CellMassMsun'].sum()

```


```
#!python traceback

Traceback (most recent call last):
  File "test2.py", line 8, in <module>
    lt['CellMassMsun'].sum()
  File "/home/goldbaum/yt-3.0/yt/data_objects/data_containers.py", line 200, in __getitem__
    self.get_data(f)
  File "/home/goldbaum/yt-3.0/yt/data_objects/data_containers.py", line 470, in get_data
    self.hierarchy._identify_base_chunk(self)
  File "/home/goldbaum/yt-3.0/yt/geometry/grid_geometry_handler.py", line 237, in _identify_base_chunk
    gi = dobj.selector.select_grids(self.grid_left_edge,
  File "/home/goldbaum/yt-3.0/yt/data_objects/data_containers.py", line 441, in selector
    raise YTDataSelectorNotImplemented(self._type_name)
yt.utilities.exceptions.YTDataSelectorNotImplemented: Data selector 'cut_region' not implemented.

```