Opened 7 years ago
Closed 7 years ago
#13903 closed defect (fixed)
polynomial .reduce returns type int over p-adic field
Reported by: | bhutz | Owned by: | AlexGhitza |
---|---|---|---|
Priority: | minor | Milestone: | sage-5.6 |
Component: | algebra | Keywords: | polynomial reduce |
Cc: | Merged in: | sage-5.6.beta3 | |
Authors: | John Perry | Reviewers: | Karl-Dieter Crisman |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
The .reduce() function for a polynomial ring can return an 'int' type when the base field is a p-adic field.
R.<y1,y2>=PolynomialRing(Qp(5),2, order='lex') G=[y1^2 + y2^2, y1*y2 + y2^2, y2^3] type((y2^3).reduce(G))
It should be returning an element of the polynomial ring.
This was noticed since it causes .variety() to fail.
R.<y1,y2>=PolynomialRing(Qp(5),2, order='lex') G=[y1^2 + y2^2, y1*y2 + y2^2, y2^3] I=ideal(G) I.variety()
Some discussion at: https://groups.google.com/forum/?fromgroups=#!topic/sage-support/Ar7z2b5cOic
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Attachments (2)
Change History (13)
comment:1 Changed 7 years ago by
- Description modified (diff)
comment:2 Changed 7 years ago by
- Description modified (diff)
And promptly broke them, as well. (It looked good before I hit submit, honest!) Okay, I'll try again...
I can work on this, if no one else has their heart set on it.
comment:3 follow-up: ↓ 4 Changed 7 years ago by
Please do! If it's a simple fix of type, maybe I can review it for you.
comment:4 in reply to: ↑ 3 Changed 7 years ago by
Replying to kcrisman:
Please do! If it's a simple fix of type, maybe I can review it for you.
It would be very easy if I could figure out how I pooched my development environment. I have a working fix, but mercurial doesn't seem to notice the changes. I hate it when this happens.
comment:5 Changed 7 years ago by
- Status changed from new to needs_review
I said it was an easy fix. This bug has burned me in other contexts, so it wasn't hard to find and fix.
comment:6 Changed 7 years ago by
- Description modified (diff)
comment:7 follow-up: ↓ 9 Changed 7 years ago by
I still get
sage: I=ideal(G) sage: I.variety() verbose 0 (3482: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. verbose 0 (1359: multi_polynomial_ideal.py, dimension) Warning: falling back to very slow toy implementation. verbose 0 (2365: multi_polynomial_ideal.py, variety) Warning: falling back to very slow toy implementation. verbose 0 (3482: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. [{y1: O(5^20), y2: O(5^20)}]
but presumably that's okay. I'm uploading a slight refresh of your patch to use our new(ish) :trac:
markup, and fixed the other non-occurrence of that in the file (there were several with the new markup already).
comment:8 Changed 7 years ago by
- Description modified (diff)
- Reviewers set to Karl-Dieter Crisman
- Status changed from needs_review to positive_review
Patchbot, apply trac_13903-reviewed.patch
comment:9 in reply to: ↑ 7 Changed 7 years ago by
Replying to kcrisman:
I still get
sage: I=ideal(G) sage: I.variety() verbose 0 (3482: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. verbose 0 (1359: multi_polynomial_ideal.py, dimension) Warning: falling back to very slow toy implementation. verbose 0 (2365: multi_polynomial_ideal.py, variety) Warning: falling back to very slow toy implementation. verbose 0 (3482: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. [{y1: O(5^20), y2: O(5^20)}]but presumably that's okay.
If you mean that the warnings are bothering you, then yes, that's okay. Unless I misread the Singular manual, it doesn't deal with Qp, though I could be wrong (I know next to nothing about p-adics, and Singular does deal with Zp). If Singular DOES implement Qp, then we haven't yet implemented that interface. That should be another ticket, though, because this bug would likely pop up even if we weren't in Qp.
I'm uploading a slight refresh of your patch to use our new(ish) :trac: markup...
Hunh. I didn't know about that. I wonder if I can remember it for the future... ;-)
comment:10 Changed 7 years ago by
Thanks. This looked good on my tests as well.
Yes, that result from .variety() is the correct final answer, well really the result is the point (1:0:0) in projective space Qp, but up to precision that is what is returned. The warnings I ignored ;)
comment:11 Changed 7 years ago by
- Merged in set to sage-5.6.beta3
- Resolution set to fixed
- Status changed from positive_review to closed
I fixed some formatting issues with the ticket description.