Fix compound regions

[keflavich]

Subcubes from region lists were untested and had some incorrect code

[coveralls]

Coverage increased (+0.03%) to 87.938% when pulling 4f27d66 on keflavich:compound_regions_fix into 6e8d71b on radio-astro-tools:master.

[keflavich]

+8.5% seems like a lot for one line....

[keflavich]

Hit a related issue pretty fast, built on #595:

In [10]: scube = cube.subcube_from_regions(reg)
Traceback (most recent call last):
  File "<ipython-input-10-946720ff5a29>", line 1, in <module>
    scube = cube.subcube_from_regions(reg)
  File "/orange/adamginsburg/repos/spectral-cube/spectral_cube/spectral_cube.py", line 1991, in subcube_from_regions
    return masked_subcube.minimal_subcube(spatial_only=True)
  File "/orange/adamginsburg/repos/spectral-cube/spectral_cube/spectral_cube.py", line 1740, in minimal_subcube
    spatial_only=spatial_only)]
  File "/orange/adamginsburg/repos/spectral-cube/spectral_cube/spectral_cube.py", line 1778, in subcube_slices_from_mask
    wcs_tolerance=self._wcs_tolerance)
  File "/orange/adamginsburg/repos/spectral-cube/spectral_cube/masks.py", line 116, in include
    return self._include(data=data, wcs=wcs, view=view)
  File "/orange/adamginsburg/repos/spectral-cube/spectral_cube/masks.py", line 407, in _include
    return np.bitwise_and(result_mask_1, result_mask_2)
TypeError: operand type(s) all returned NotImplemented from __array_ufunc__(<ufunc 'bitwise_and'>, '__call__', dask.array<getitem, shape=(1920, 188, 62), dtype=float64, chunksize=(40, 28, 28)>, array([[[False, False, False, ..., False,
False, False],
...
        [False, False, False, ..., False, False, False]]])): 'Array', 'ndarray'

[keflavich]

I guess dask hasn't implemented the bitwise_and operation?

ipdb> np.logical_and(result_mask_1, result_mask_1)
dask.array<logical_and, shape=(1920, 188, 62), dtype=bool, chunksize=(40, 28, 28)>                                                                                                                                                          
ipdb> np.bitwise_and(result_mask_1, result_mask_1)
*** TypeError: operand type(s) all returned NotImplemented from __array_ufunc__(<ufunc 'bitwise_and'>, '__call__', dask.array<getitem, shape=(1920, 188, 62), dtype=float64, chunksize=(40, 28, 28)>, dask.array<getitem, shape=(1920, 188, 62), dtype=float64, chunksize=(40, 28, 28)>): 'Array', 'Array'

[astrofrog]

Looks good to me (ignoring the dask issue) but maybe add a changelog entry if this is a bug that could have affected users?