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`cupy.ndarray` cannot be compared with ellipsis

See original GitHub issue

Not sure if it’s due to #4198. The __richcmp__ method does not handle trivial comparison with Python objects correctly:

>>> np.empty(3) == ...
array([False, False, False])
>>>
>>> cp.empty(3) == ...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "cupy/_core/core.pyx", line 1094, in cupy._core.core.ndarray.__richcmp__
    return numpy.equal(self, other)
TypeError: operand type(s) all returned NotImplemented from __array_ufunc__(<ufunc 'equal'>, '__call__', array([0., 0., 0.]), Ellipsis): 'ndarray', 'ellipsis'

It seems NumPy internally calls PyObject_RichCompare to handle this. Perhaps before delegating to numpy.equal() (and friends) we should handle this edge case first?

Issue Analytics

State:
Created 2 years ago
Comments:8 (7 by maintainers)

Top GitHub Comments

2reactions

toslunarcommented, Sep 8, 2021

#1989 discusses comparison with None.

0reactions

takagicommented, Dec 17, 2021

As @toslunar mentioned in https://github.com/cupy/cupy/issues/5715#issuecomment-985991356, I think NumPy’s current code works without any problem. But, yes, your diff would be exactly what we want to do there.