Opened 12 years ago
Closed 9 years ago
#10308 closed defect (fixed)
bug in genus of ideal on 64 bits
Reported by: | Luis Felipe Tabera Alonso | Owned by: | William Stein |
---|---|---|---|
Priority: | major | Milestone: | sage-5.11 |
Component: | interfaces | Keywords: | genus, Singular, 64bits |
Cc: | Merged in: | sage-5.11.rc0 | |
Authors: | Luis Felipe Tabera Alonso | Reviewers: | Peter Bruin |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
The following problem was discovered by Victor Miller in Sage-support
http://groups.google.com/group/sage-support/browse_thread/thread/e30af8c695b6a912
sage: T.<t1,t2,u1,u2> = QQ[] sage: TJ = Ideal([t1^2 + u1^2 - 1,t2^2 + u2^2 - 1, (t1-t2)^2 + (u1-u2)^2 -1]) sage: TJ.genus() 4294967295 sage: TJ.dimension() 1
I can confirm the bug in debian 64bits. Howeber, in debian 32 bits the answer is
sage: TJ.genus() -1
So it seems to be a problem with 232-1 in 32 vs 64 bits.
A simpler example (Ubuntu 64-bit):
sage: R.<x, y, z> = QQ[] sage: C = Curve(x^2 - 2*y^2) sage: C.is_singular() True sage: C.genus() 4294967295
Attachments (1)
Change History (7)
comment:1 Changed 12 years ago by
Description: | modified (diff) |
---|
Changed 10 years ago by
Attachment: | 10380.patch added |
---|
comment:2 Changed 10 years ago by
Status: | new → needs_review |
---|
comment:4 Changed 10 years ago by
Authors: | → Luis Felipe Tabera Alonso |
---|
comment:5 Changed 9 years ago by
Reviewers: | → Peter Bruin |
---|---|
Status: | needs_review → positive_review |
The bug does not appear to be present in 5.11.beta3, the patch applies and the tests that it introduces run correctly. Note that the answer -1
is really the (geometric) genus, not an error code (as one could be led to suspect by the sage-support discussion cited above).
comment:6 Changed 9 years ago by
Merged in: | → sage-5.11.rc0 |
---|---|
Resolution: | → fixed |
Status: | positive_review → closed |
It seems to me that the bug is solved in linux 64 bits with newer versions of Sage.
I attach a doctest for the record.