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Model evaluation crashes if some inputs are scalars #10170
Description
Edited
I originally posted this because I thought it was specific to fix_inputs, but it's more fundamental than that, this is a revised description.
Description
A model can be called with some inputs as scalars and some as arrays/lists, with the scalars being broadcasted to the same shape as the other inputs. After evaluation, the output is rebroadcast by prepare_outputs() but this checks the shapes of the outputs against the shapes of the inputs, and crashes if any of the first n_outputs inputs were scalars.
Expected behavior
I should get identical results from, but the first works and the second crashes.
>>> g = Gaussian2D(1, 2, 3, 4, 5)
>>> g([2.5,2.5], 1)
>>> g(2.5, [1,1])
Actual behavior
ValueError: can only convert an array of size 1 to a Python scalar
Steps to Reproduce
>>> from astropy.modeling.models import Gaussian2D
>>> g = Gaussian2D(1, 2, 3, 4, 5)
>>> g([2.5,2.5], 1)
array([0.9159326, 0.9159326])
>>> g(2.5, [1,1]) # should be the same
Traceback (most recent call last):
...
ValueError: can only convert an array of size 1 to a Python scalar
System Details
Python 3.7.6 (default, Jan 8 2020, 13:42:34)
[Clang 4.0.1 (tags/RELEASE_401/final)]
Numpy 1.18.1
astropy 4.0
Scipy 1.4.1
Activity
[-]fix_inputs fails to expand value into array if other inputs are arrays[/-][+]Model evaluation crashes if some inputs are scalars[/+]nden commentedon Apr 20, 2020
Thanks for the report. I think this is related to #9953 and the first example works only by accident.
astropy-bot commentedon Apr 28, 2020
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Potential fix for issue astropy#10170
Added tests to show that issue astropy#10170 is fixed.
Potential fix for issue astropy#10170