Opened 5 years ago
Closed 5 years ago
#20435 closed defect (fixed)
factorisation of polynomials over integers has wrong parent
Reported by: | chapoton | Owned by: | |
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Priority: | critical | Milestone: | sage-7.2 |
Component: | algebra | Keywords: | factor, polynomial, parent |
Cc: | tscrim, jdemeyer | Merged in: | |
Authors: | Frédéric Chapoton | Reviewers: | Bruno Grenet |
Report Upstream: | N/A | Work issues: | |
Branch: | 3e28bfc (Commits, GitHub, GitLab) | Commit: | 3e28bfc536ac1b69c365213f4ff385874b6aee1e |
Dependencies: | Stopgaps: |
Description (last modified by )
sage: x,y=polygen(ZZ,'x,y') sage: p=x**2-y**2 sage: p.parent() Multivariate Polynomial Ring in x, y over Integer Ring sage: factor(p) (x - y) * (x + y) sage: factor(p)[0][0].parent() Multivariate Polynomial Ring in x, y over Multivariate Polynomial Ring in x, y over Integer Ring
but no problem over QQ
Change History (7)
comment:1 Changed 5 years ago by
- Cc tscrim jdemeyer added
- Description modified (diff)
comment:2 Changed 5 years ago by
- Keywords factor polynomial parent added
- Priority changed from major to critical
comment:3 Changed 5 years ago by
comment:4 Changed 5 years ago by
- Branch set to public/20435
- Commit set to 5ec9040c9bbf46103eec0505cfec1e350f414dbf
- Status changed from new to needs_review
New commits:
5ec9040 | trac #20435 fixing the parents in factorisation of integer multi-polynomials
|
comment:5 Changed 5 years ago by
- Commit changed from 5ec9040c9bbf46103eec0505cfec1e350f414dbf to 3e28bfc536ac1b69c365213f4ff385874b6aee1e
Branch pushed to git repo; I updated commit sha1. New commits:
3e28bfc | trac #20435 correct link to trac
|
comment:6 Changed 5 years ago by
- Reviewers set to Bruno Grenet
- Status changed from needs_review to positive_review
Sorry for that! The correction looks good to me.
P.S.: I suspected that using f[0].change_ring(self._parent.base_ring())
would have been faster than the conversion self._parent(f[0])
but it appears not to be the case!
comment:7 Changed 5 years ago by
- Branch changed from public/20435 to 3e28bfc536ac1b69c365213f4ff385874b6aee1e
- Resolution set to fixed
- Status changed from positive_review to closed
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caused by the line
in #17840