Opened 10 years ago
Closed 9 years ago
#11372 closed defect (fixed)
nasty side effect of a failed simon_two_descent search
Reported by: | was | Owned by: | cremona |
---|---|---|---|
Priority: | critical | Milestone: | sage-5.0 |
Component: | elliptic curves | Keywords: | rd2 |
Cc: | Merged in: | sage-5.0.beta11 | |
Authors: | William Stein | Reviewers: | Jennifer Balakrishnan |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
This could seriously confuse a person:
deep:sage-4.7.rc1 wstein$ ./sage ---------------------------------------------------------------------- | Sage Version 4.7.rc1, Release Date: 2011-04-29 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- sage: E = EllipticCurve([1, 1, 0, -23611790086, 1396491910863060]) sage: E.simon_two_descent() (1, 2, [(88716 : -44358 : 1)]) sage: E.gens() [] sage: E.rank() 0 sage: E = EllipticCurve([1, 1, 0, -23611790086, 1396491910863060]) sage: E.gens() [(4311692542083/48594841 : -13035144436525227/338754636611 : 1)]
The point that simon_two_descent finds is a torsion point. But for some reason E then thinks it has rank 0! Even though simon_two_descent's first output was 1, and in fact E has rank 1. This is pretty scary.
Related: #11005 (Update Simon's GP scripts and convert to use via gp2c)
Attachments (1)
Change History (9)
comment:1 Changed 10 years ago by
- Description modified (diff)
comment:2 Changed 10 years ago by
comment:3 Changed 9 years ago by
- Stopgaps set to #12695
Changed 9 years ago by
comment:4 Changed 9 years ago by
- Status changed from new to needs_review
comment:5 Changed 9 years ago by
- Reviewers set to Jennifer Balakrishnan
comment:6 Changed 9 years ago by
- Keywords rd2 added
- Status changed from needs_review to positive_review
- Stopgaps #12695 deleted
Looks great, and all tests pass.
Could someone else go to the stopgap ticket (#12695) and mark that it's no longer needed?
comment:7 Changed 9 years ago by
comment:8 Changed 9 years ago by
- Merged in set to sage-5.0.beta11
- Resolution set to fixed
- Status changed from positive_review to closed
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This may be a dup, because Cremona says: "Yet another one of many related bugs being looked at and/or already fixed, see #10832 and #11005 and #11130 and ...."