Opened 7 years ago
Last modified 6 years ago
#18251 new defect
Equality comparison with 0 is not consistant — at Initial Version
| Reported by: | tscrim | Owned by: | tscrim |
|---|---|---|---|
| Priority: | critical | Milestone: | sage-7.4 |
| Component: | coercion | Keywords: | zero |
| Cc: | nthiery, darij, nbruin, robertwb, chapoton, vdelecroix | Merged in: | |
| Authors: | Reviewers: | ||
| Report Upstream: | N/A | Work issues: | |
| Branch: | Commit: | ||
| Dependencies: | Stopgaps: |
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Description
Currently we have the following in Sage:
sage: C = CombinatorialFreeModule(QQ, ['a','b']) sage: C.zero() == ZZ(0) True sage: C.zero() == QQ(0) False sage: M.zero() (0, 0, 0, 0) sage: M.zero() == ZZ(0) True sage: M.zero() == QQ(0) False
What I've been doing has been implementing a custom __eq__ which checks explicitly for the other argument is 0 and then checking self.is_zero. However I'm thinking we should have a general fix with this as a special case, but we could do it just for these element classes.
Additionally this works when there a coercion from the base ring. I guess more generally do we want equality checking for when there is a conversion to the base ring? Thoughts?
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