Opened 4 years ago
Closed 4 years ago
#18467 closed defect (fixed)
PolynomialRealDense.quo_rem() returns zero polynomials with wrong degree
Reported by: | pbruin | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-6.8 |
Component: | basic arithmetic | Keywords: | polynomial degree quo_rem |
Cc: | Merged in: | ||
Authors: | Peter Bruin | Reviewers: | Bruno Grenet |
Report Upstream: | N/A | Work issues: | |
Branch: | 9dc90cc (Commits) | Commit: | 9dc90cc9367a016745c85326d7a8abfabe2e3d53 |
Dependencies: | Stopgaps: |
Description
In Sage 6.7, the following is correct:
sage: R.<x> = QQ[] sage: z = R.zero() sage: z.degree() -1 sage: q, r = z.quo_rem(x) sage: q.degree() -1
The following (QQ
-> RR
) is not:
sage: S.<x> = RR[] sage: z = S.zero() sage: z.degree() -1 sage: q, r = z.quo_rem(x) sage: q.degree() -2
The last result should be -1
; the given answer implies for example
sage: q == z False
which is nonsense since q
and z
are both the zero polynomial.
Change History (5)
comment:1 Changed 4 years ago by
- Branch set to u/pbruin/18467-quo_rem
- Commit set to 9dc90cc9367a016745c85326d7a8abfabe2e3d53
- Status changed from new to needs_review
comment:2 follow-up: ↓ 3 Changed 4 years ago by
- Reviewers set to Bruno Grenet
comment:3 in reply to: ↑ 2 ; follow-up: ↓ 4 Changed 4 years ago by
Replying to bruno:
Looks fine to me! A minor comment: It seems that people prefer not referring to
`self`
in the documentation
If you really insist I can change it, but I personally prefer self
over this polynomial
(see comment:5:ticket:13442).
There was some recent discussion on a related question, namely whether self
should be documented in INPUT
sections of methods. On that question I agree with most people that it should not.
comment:4 in reply to: ↑ 3 Changed 4 years ago by
- Status changed from needs_review to positive_review
Replying to pbruin:
Replying to bruno:
Looks fine to me! A minor comment: It seems that people prefer not referring to
`self`
in the documentationIf you really insist I can change it, but I personally prefer
self
overthis polynomial
(see comment:5:ticket:13442).There was some recent discussion on a related question, namely whether
self
should be documented inINPUT
sections of methods. On that question I agree with most people that it should not.
Actually, I was referring to (the beginning of) this discussion. Yet there does not seem to be a consensus. And I do not have a strong opinion on this... so I do not insist!
comment:5 Changed 4 years ago by
- Branch changed from u/pbruin/18467-quo_rem to 9dc90cc9367a016745c85326d7a8abfabe2e3d53
- Resolution set to fixed
- Status changed from positive_review to closed
Looks fine to me! A minor comment: It seems that people prefer not referring to
`self`
in the documentation, so you could replace the documentation of this function by