Smoothing with 3D

[matthew-w-lundy]

Running with

config['io']['3d_bkg'] = True

and

config['background_selection']['smooth'] = True

results in the following error when running:

config = run_make_background(config)

 RemoteTraceback                           Traceback (most recent call last)
RemoteTraceback: 
"""
Traceback (most recent call last):
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py", line 125](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py#line=124), in worker
    result = (True, func(*args, **kwds))
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py", line 48](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py#line=47), in mapstar
    return list(map(*args))
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/make_background.py", line 184](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/make_background.py#line=183), in get_background_for_run
    hdul.append(estimator.background_rate.to_table_hdu())
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/background_models.py", line 393](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/background_models.py#line=392), in background_rate
    rate = smooth(rate, sigma=self.smooth_sigma)
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/background_models.py", line 415](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/background_models.py#line=414), in smooth
    offset = bkg.axes['offset'].center.value
  File "[/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy/maps/axes.py", line 1821](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy/maps/axes.py#line=1820), in __getitem__
    raise KeyError(f"No axes: {idx!r}")
KeyError: "No axes: 'offset'"
"""

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)
Cell In[61], line 1
----> 1 config = run_make_background(config)

File [~/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/make_background.py:450](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/site-packages/gammapy_tools/make_background/make_background.py#line=449), in run_make_background(config)
    448     map_fn = get_background_for_run
    449     with Pool(1) as pool:
--> 450         output = pool.map(map_fn, obs_parameters)
    452 if from_run:
    453     flist = output

File [~/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py:364](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py#line=363), in Pool.map(self, func, iterable, chunksize)
    359 def map(self, func, iterable, chunksize=None):
    360     '''
    361     Apply `func` to each element in `iterable`, collecting the results
    362     in a list that is returned.
    363     '''
--> 364     return self._map_async(func, iterable, mapstar, chunksize).get()

File [~/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py:771](http://localhost:8888/home/matthew/anaconda3/envs/mamba/envs/gammapy1/lib/python3.10/multiprocessing/pool.py#line=770), in ApplyResult.get(self, timeout)
    769     return self._value
    770 else:
--> 771     raise self._value

KeyError: "No axes: 'offset'"

[steob92]

3D Backgrounds maker isn't passing the smoothing method:
https://github.com/VERITAS-Observatory/gammapy-tools/blob/2d46ac43dea4afe36dca0ec3cf3619a7fa0fce5b/gammapy_tools/make_background/background_models.py#L389C1-L395C1

So it defaults to poly, which explicitly assumes a 2D background:
https://github.com/VERITAS-Observatory/gammapy-tools/blob/2d46ac43dea4afe36dca0ec3cf3619a7fa0fce5b/gammapy_tools/make_background/background_models.py#L414C1-L419C38

Suggest just adding a value in the config file that then gets passes to smooth:

https://github.com/VERITAS-Observatory/gammapy-tools/blob/2d46ac43dea4afe36dca0ec3cf3619a7fa0fce5b/gammapy_tools/templates/config.py#L64C1-L64C21

There needs to be some check if the method matches 2D/3D background.

Alternatively just add:

        if type(bkg) == gammapy.irf.background.Background2D:
            bkg = bkg.to_3d()

To convert between the background types.

[steob92]

@matthew-w-lundy can you test with f17a55b?