#10308: bug in genus of ideal on 64 bits
--------------------------+-------------------------------------------------
Reporter: lftabera | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-4.6.2
Component: interfaces | Keywords: genus, Singular, 64bits
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
--------------------------+-------------------------------------------------
Description changed by davidloeffler:
Old description:
> 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
> anser is
>
> {{{
> sage: TJ.genus()
> -1
> }}}
>
> So it seems to be a problem with 2**32-1 in 32 vs 64 bits.
New description:
The following problem was discovered by Victor Miller in Sage-support
http://groups.google.com/group/sage-
support/browse_thread/thread/e30af8c695b6a912
{{{
#!python
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 2**32-1 in 32 vs 64 bits.
A simpler example (Ubuntu 64-bit):
{{{
#!python
sage: R.<x, y, z> = QQ[]
sage: C = Curve(x^2 - 2*y^2)
sage: C.is_singular()
True
sage: C.genus()
4294967295
}}}
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10308#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
