Repository navigation
Inputs to modeling not always broadcasted as expected #11060
Description
Description
This might not actually be a bug and nobody but me expects it to work this way, but this worked when I ran the same code through astropy.wcs.WCS and it fails with gwcs.WCS because of the input behaviour in modeling.
Expected behavior
When calling a 2D model with sparse, broadcastable inputs I expect the inputs to be broadcasted together.
Actual behavior
Traceback saying ValueError: All inputs must have identical shapes or must be scalars.
Steps to Reproduce
import numpy as np
from astropy.modeling import models
import astropy.units as u
shape = (3, 3)
data = np.arange(np.product(shape)).reshape(shape) * u.m / u.s
points_unit = u.pix
points = [np.arange(size) * points_unit for size in shape]
kwargs = {
'bounds_error': False,
'fill_value': np.nan,
'method': 'nearest',
}
transform = models.Tabular2D(points, data, **kwargs)
print(transform)Model: Tabular2D
N_inputs: 2
N_outputs: 1
Parameters:
points: [<Quantity [0., 1., 2.] pix>, <Quantity [0., 1., 2.] pix>]
lookup_table: [[0. 1. 2.]
[3. 4. 5.]
[6. 7. 8.]] m / s
method: nearest
fill_value: nan
bounds_error: False
points = np.meshgrid(np.arange(3), np.arange(3), indexing='ij', sparse=True)
print(points)[array([[0],
[1],
[2]]), array([[0, 1, 2]])]
transform(*points)---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-14-e007ddf28445> in <module>
----> 1 import codecs, os;__pyfile = codecs.open('''/tmp/pypuTmFL''', encoding='''utf-8''');__code = __pyfile.read().encode('''utf-8''');__pyfile.close();os.remove('''/tmp/pypuTmFL''');exec(compile(__code, '''/tmp/pypuTmFL''', 'exec'));
/tmp/pypuTmFL in <module>
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in __call__(self, model_set_axis, with_bounding_box, fill_value, equivalencies, inputs_map, *inputs, **new_inputs)
398 ('inputs_map', None)])
399
--> 400 new_call = make_function_with_signature(
401 __call__, args, kwargs, varargs='inputs', varkwargs='new_inputs')
402
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in __call__(self, *inputs, **kwargs)
377 def __call__(self, *inputs, **kwargs):
378 """Evaluate this model on the supplied inputs."""
--> 379 return super(cls, self).__call__(*inputs, **kwargs)
380
381 # When called, models can take two optional keyword arguments:
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in __call__(self, *args, **kwargs)
911 new_args, kwargs = self._get_renamed_inputs_as_positional(*args, **kwargs)
912
--> 913 return generic_call(self, *new_args, **kwargs)
914
915 def _get_renamed_inputs_as_positional(self, *args, **kwargs):
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in generic_call(self, *inputs, **kwargs)
3945 def generic_call(self, *inputs, **kwargs):
3946 """ The base ``Model. __call__`` method."""
-> 3947 inputs, format_info = self.prepare_inputs(*inputs, **kwargs)
3948 if isinstance(self, CompoundModel):
3949 # CompoundModels do not normally hold parameters at that level
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in prepare_inputs(self, model_set_axis, equivalencies, *inputs, **kwargs)
1608 inputs = [np.asanyarray(_input, dtype=float) for _input in inputs]
1609
-> 1610 _validate_input_shapes(inputs, self.inputs, n_models,
1611 model_set_axis, self.standard_broadcasting)
1612
~/.virtualenvs/ndcube-dev/lib/python3.8/site-packages/astropy/modeling/core.py in _validate_input_shapes(inputs, argnames, n_models, model_set_axis, validate_broadcasting)
3885 input_shape = check_consistent_shapes(*all_shapes)
3886 if input_shape is None:
-> 3887 raise ValueError(
3888 "All inputs must have identical shapes or must be scalars.")
3889
ValueError: All inputs must have identical shapes or must be scalars.
What I expect the output to be is what happens if you set sparse=False:
points = np.meshgrid(np.arange(3), np.arange(3), indexing='ij', sparse=False) * u.pix
print(transform(*points))[[[0. 0. 0.]
[1. 1. 1.]
[2. 2. 2.]]
[[0. 1. 2.]
[0. 1. 2.]
[0. 1. 2.]]] pix
System Details
Astropy 4.1
Activity
nden commentedon Nov 19, 2020
This is a known issue. I attempted a solution in #10362 but it's incomplete - handling of the bounding box needs to be fixed. Similar issues: #9953 , #10170
pllim commentedon Nov 19, 2020
Closing as duplicate. Thanks!
WilliamJamieson commentedon Apr 15, 2021
Even with the changes in #11548 I still get a crash with this example. Though it is slightly different. @nden can you reopen this?
WilliamJamieson commentedon Apr 15, 2021
With current changes in #11548 when I try:
The error:
WilliamJamieson commentedon Apr 15, 2021
Note that the above unit error can be resolved by running instead running:
However, this creates another shaping error which is related to the others fixed in #11548:
I have a possible fix for this crash. However I am not convinced that I get the correct answer back when I use this fix. Namely, under my fix the above code would return:
Does this seem reasonable?
Possible fix for issue astropy#11060.
Added test to show astropy#11060 has been fixed
nden commentedon Apr 22, 2021
@WilliamJamieson 👍 The above numbers match the answer without units.
Modified tabular so that both inputs in issue astropy#11060 produce s…
Potential fix for issue astropy#10170