Opened 11 years ago
Closed 8 years ago
#10168 closed defect (fixed)
fraction field of InfinitePolynomialRing
Reported by: | chapoton | Owned by: | malb |
---|---|---|---|
Priority: | minor | Milestone: | sage-5.12 |
Component: | commutative algebra | Keywords: | fraction field; polynomial ring |
Cc: | sage-combinat | Merged in: | sage-5.12.beta4 |
Authors: | Frédéric Chapoton | Reviewers: | Travis Scrimshaw |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
I would like to use the fraction field of infinite polynomial ring.
sage: P.<x,y> = InfinitePolynomialRing(QQ, implementation='sparse') sage: z=P(x[1]) sage: 1/z
So far, one gets
NotImplementedError: Fraction Fields of Infinite Polynomial Rings are not implemented
This seems to be a coercion problem.
Attachments (1)
Change History (16)
comment:1 Changed 11 years ago by
comment:2 Changed 11 years ago by
comment:3 Changed 10 years ago by
- Description modified (diff)
comment:4 Changed 10 years ago by
- Description modified (diff)
comment:5 Changed 8 years ago by
It seems now that the example of comment 1 does no longer work.
Here is a proposed patch, that could have worked maybe.
comment:6 Changed 8 years ago by
- Cc sage-combinat added
- Status changed from new to needs_info
- Work issues set to coercion problem
comment:7 Changed 8 years ago by
Here is a patch that works (but there is a problem still with reduction)
comment:8 Changed 8 years ago by
The main problem comes from the gcd :
sage: R.<x>=InfinitePolynomialRing(QQ) sage: p1=x[0]+x[0]**2 sage: p1.gcd(p1)
fails completely.
comment:9 Changed 8 years ago by
well, it almost works now. I have added a custom gcd procedure.
I am not sure that this is the correct way to handle these problems. If somebody has a better idea ?
comment:10 Changed 8 years ago by
- Status changed from needs_info to needs_review
comment:11 Changed 8 years ago by
- Keywords polynomial ring added
- Milestone set to sage-6.0
- Work issues coercion problem deleted
comment:12 Changed 8 years ago by
I think this is the right way since the gcd
needed an implementation. However I have a few comments:
- Could you add some tests showing that you get something in the fraction field?
- Now we don't need the
# indirect doctest
for any method with a leading and trailing underscore. - Are you pushing this off to 6.0 because of the large number of changes to the file? I don't think this is really touched often, so I don't expect there to be rebasing problems and we should try to get this into sage-5.12 IMO.
Best,
Travis
Changed 8 years ago by
comment:13 Changed 8 years ago by
- Milestone changed from sage-6.0 to sage-5.12
Hello again,
Thanks for looking at my code. Here is an updated patch.
- I have removed the "#indirect doctests" in _div_
- I have added two .parent() tests in _div_
- I have set back the milestone to 5.12 (I have no good reason to postpone)
comment:14 Changed 8 years ago by
- Reviewers set to Travis Scrimshaw
- Status changed from needs_review to positive_review
Looks good to me. Thanks Frederic.
comment:15 Changed 8 years ago by
- Merged in set to sage-5.12.beta4
- Resolution set to fixed
- Status changed from positive_review to closed
Also note that this seems to work (at least a little bit):