#11526 closed defect (fixed)
count_points() error for generic schemes. (includes patch)
Reported by: | mmarco | Owned by: | AlexGhitza |
---|---|---|---|
Priority: | major | Milestone: | sage-4.8 |
Component: | algebraic geometry | Keywords: | |
Cc: | Merged in: | sage-4.8.alpha4 | |
Authors: | Miguel Marco, David Eklund, Frithjof Schulze | Reviewers: | Johan Bosman, Julian Rueth |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
sage raises an error when trying to count the number of points of a subscheme of an affine scheme.
See, for instance:
sage: F=FiniteField(3) sage: R.<x,y>=F[] sage: A=AffineSpace(F,2) sage: I=R.ideal(x^2-y^2-1) sage: S=A.subscheme(I) sage: S.count_points(2) --------------------------------------------------------------------------- NameError Traceback (most recent call last) /home/mmarco/sage-4.6.2/<ipython console> in <module>() /usr/lib64/python2.7/site-packages/sage/schemes/generic/scheme.py in count_points(self, n) 531 F1 = GF(q**i, name='z') 532 S1 = self.base_extend(F1) --> 533 a.append(len(S1.rational_points())) 534 return(a) 535 /usr/lib64/python2.7/site-packages/sage/schemes/generic/algebraic_scheme.py in rational_points(self, F, bound) 1129 raise TypeError, "Unable to enumerate points over %s."%F 1130 try: -> 1131 return X.points() 1132 except TypeError: 1133 raise TypeError, "Unable to enumerate points over %s."%F /usr/lib64/python2.7/site-packages/sage/schemes/generic/homset.py in points(self, B) 162 except TypeError: 163 raise TypeError, "Domain of argument must be of the form Spec(S)." --> 164 if is_RationalField(R) or R == Z: 165 if not B > 0: 166 raise TypeError, "A positive bound B (= %s) must be specified."%B NameError: global name 'Z' is not defined
Apply:
Attachments (5)
Change History (15)
Changed 10 years ago by
comment:1 Changed 10 years ago by
- Description modified (diff)
comment:2 Changed 10 years ago by
- Status changed from new to needs_review
comment:3 Changed 10 years ago by
Changed 10 years ago by
In addition to fixing the bug, the patch includes a doctest illustrating this.
comment:4 Changed 10 years ago by
- Description modified (diff)
The patch trac_11526_bugfix_with_doctest.patch was made using Sage 4.7.1.
comment:5 Changed 10 years ago by
- Status changed from needs_review to needs_work
Now that you're working on the docstring anyway, it would be good to add INPUT and OUTPUT sections to it, as is the standard convention.
comment:6 Changed 10 years ago by
- Description modified (diff)
- Status changed from needs_work to needs_review
The patch trac_11526_bugfix_with_docstring.patch was made using Sage 4.7.1.
Changed 10 years ago by
fixes the bug (also for the projective case), docstring with Input and Output.
comment:7 Changed 10 years ago by
- Description modified (diff)
- Reviewers set to Johan Bosman, Julian Rueth
- Status changed from needs_review to positive_review
Apply trac_11526_final.patch
Tested against sage-4.8.alpha3 and doctests pass.
trac_11526_final.patch is identical to [trac_11526_bugfix_with_docstring.2.patch] except for the commit message which I replaced with something that makes hopefully more sense to somebody who does not know this ticket.
We still don't have a docstring for SchemeHomset?_projective_coordinates_ring.points() but I guess that is acceptable since there wasn't any before and it's not implemented anyway.
I'm unsure if "Reviewers" should only mention the person who clicked "positive review" or everybody who was part of the review process. Anyway, I added some authors and reviewers, I hope nobody minds.
Btw. davideklund, your name is not in the AccountNamesMappedtoRealNames? on the trac wiki start page.
comment:8 Changed 10 years ago by
comment:9 Changed 10 years ago by
- Merged in set to sage-4.8.alpha4
- Resolution set to fixed
- Status changed from positive_review to closed
The patch makes sense, it fixes a bug in the method points() of the class SchemeHomset_affine_coordinates.
Note: the same typo (Z instead of ZZ) seems to occur in the method points() of the class SchemeHomset_projective_coordinates_ring, which is not implemented yet.