morphology_parameters: AttributeErrror

[Elisa-Visentin]

Hi,
Sorry for the banal question but... While computing morphology parameters (morphology_parameters(...)) on a set of images with ctapipe 0.19.0, some of the events make the script crash with the following error lines

Traceback (most recent call last):
  File "/home/evisentin/Desktop/lstchain/magic-cta-pipe/magicctapipe/scripts/lst1_magic/lst1_magic_mc_dl0_to_dl1.py", line 522, in <module>
    main()
  File "/home/evisentin/Desktop/lstchain/magic-cta-pipe/magicctapipe/scripts/lst1_magic/lst1_magic_mc_dl0_to_dl1.py", line 513, in main
    mc_dl0_to_dl1(args.input_file, args.output_dir, config)
  File "/home/evisentin/Desktop/lstchain/magic-cta-pipe/magicctapipe/scripts/lst1_magic/lst1_magic_mc_dl0_to_dl1.py", line 343, in mc_dl0_to_dl1
    morphology_params = morphology_parameters(
  File "/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/ctapipe/image/morphology.py", line 194, in morphology_parameters
    n_islands, island_labels = number_of_islands(geom=geom, mask=image_mask)
  File "/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/ctapipe/image/morphology.py", line 74, in number_of_islands
    neighbors = geom.neighbor_matrix_sparse
  File "/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/astropy/utils/decorators.py", line 841, in __get__
    val = self.fget(obj)
  File "/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/ctapipe/instrument/camera/geometry.py", line 682, in neighbor_matrix_sparse
    return self.calc_pixel_neighbors(diagonal=False)
  File "/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/ctapipe/instrument/camera/geometry.py", line 740, in calc_pixel_neighbors
    if (neighbor_matrix.T != neighbor_matrix).sum() > 0:
AttributeError: 'bool' object has no attribute 'sum'

whereas other events (same script, same input file) are well reconstructed or only return a warning

/home/evisentin/mambaforge/envs/lstchain/lib/python3.9/site-packages/ctapipe/instrument/camera/geometry.py:741: UserWarning: Neighbor matrix is not symmetric. Is camera geometry irregular?
  warnings.warn(

which needs this if to be executed.
Maybe some events need a lot of memory to be processed? Or are there some 'anomalous' images on which the morphology_parameters algorithm fails? Other issues (dependencies...)?

Thanks.

[Tobychev]

Hi @Elisa-Visentin, it looks like you've come across a bug! Please create an issue reporting the problem 🙏

Probably some of your image contains single pixels that somehow survive cleaning and thus result in neightbour matrices that contain only a single value and are thus not proper numpy arrays, which is why the comparison results in a bool type variable instead of an array of values that does have the sum attribute.

[maxnoe]

Normally, we require events to have at least a couple of pixels after the cleaning to be included in the parametrizations, which is probably why this wasn't noticed before.

[maxnoe]

@Tobychev we can just convert discussions into issues

[maxnoe]

See #2316

[Elisa-Visentin]

Thank you. Actually, in the script (magic-cta-pipe, lst1_magic_mc_dl0_to_dl1.py), events are skipped before parameterization only if no pixel survive the cleaning step, and morphology parameters were not evaluated up to now (I think) so I never run into this error before. Sorry (I didn't want to disturb you so much)

[maxnoe]

@Elisa-Visentin You identified a real issue, which I opened in #2316, so please don't worry about bothering us.

Instead, keep bothering us a bit more if you find more issues ;)