Opened 7 years ago
Last modified 4 weeks ago
#15297 new defect
Elements from a Field of Fractions that compare equal should have equal hashes
Reported by: | Stefan | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-9.2 |
Component: | algebra | Keywords: | field of fractions, hashing |
Cc: | yzh, mkoeppe | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Sage can't guarantee that p == q
implies hash(p) == hash(q)
, but it is not unreasonable to strive to make this work in case p,q
belong to the same ring or field.
This ticket deals with Fields of Fractions. The proposed solution from this post appears to do the trick: https://groups.google.com/forum/#!topic/sage-devel/TOp_5LCBBR4
Example:
sage: R.<x> = ZZ['x'] sage: F = R.fraction_field() sage: p = 1/(1-x) sage: q = (-1)/(x-1) sage: p == q True sage: hash(p) == hash(q) False
Change History (6)
comment:1 Changed 6 years ago by
- Milestone changed from sage-6.1 to sage-6.2
comment:2 Changed 6 years ago by
- Milestone changed from sage-6.2 to sage-6.3
comment:3 Changed 6 years ago by
- Milestone changed from sage-6.3 to sage-6.4
comment:4 Changed 5 years ago by
- Cc yzh mkoeppe added
comment:5 Changed 20 months ago by
- Milestone changed from sage-6.4 to sage-8.4
comment:6 Changed 4 weeks ago by
- Milestone changed from sage-8.4 to sage-9.2
Still broken in 9.1.rc2
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Still broken even with #16268; see #26339.