Which ticket? Thanks,  William
On Dec 16, 2011 7:56 PM, "syd.lavas...@gmail.com" <syd.lavas...@gmail.com>
wrote:

> Hi William,
>
> Thank you for you advices. I wrote the wrapper and submitted it. I
> also checked the singular's code briefly. It seems that fundamentally
> the same as the one I cited in counting singularities. I'm going to
> contatct Florian Hess to ask him about the best algorithm.
>
> On Dec 14, 12:34 am, William Stein <wst...@gmail.com> wrote:
> > On Tue, Dec 13, 2011 at 3:57 PM, syd.lavas...@gmail.com
> >
> > <syd.lavas...@gmail.com> wrote:
> > > AFAIK, currently the function field object can not compute itsgenus
> > > (see below). I'm thinking about adding this feature in following few
> > > days. Now, there are two different approaches I can take, and I would
> > > like to know which one is more desirable for Sage community:
> >
> > > 1. Sage can use singular to compute thegenus, so we can write
> > > (essentially) a wrapper which compute thegenusand make it a member
> > > of the function field class.
> >
> > What function field object are you talking about?    Do you mean the
> code at
> >
> >    http://trac.sagemath.org/sage_trac/ticket/9054
> >
> > which isn't included in any version of Sage yet, but has a positive
> review?
> >
> >
> >
> > > 2. To implement the algorithm (for example the one in [1]) from
> > > scratch.
> >
> > > Please, tell me which one is the more desirable approach. If anybody
> > > has any comment or has already the implementation please bring it up
> > > in the discussion.
> >
> > I think one should of course at a minimum do 1 (wrap singular),
> > because it will be easy.  Then do 2 as well, if you can -- and make it
> > easy to compare 1 and 2 on many inputs, so you can find lots of bugs
> > in both.  Also do 3, which is to implement whatever algorithm Florian
> > Hess suggests, which might be different than 1 or 2.
> >
> >  -- William
> >
> >
> >
> >
> >
> >
> >
> > > [1] Sendra, J. R. and Winkler, F. and Pérez-Díaz, S., Rational
> > > Algebraic Curves - A Computer Algebra Approach, Springer, 2007.
> >
> > > sage: kx.<x> = FunctionField(QQ)
> > > sage: kxY.<Y> = PolynomialRing(kx, 'Y')
> > > sage: kxy.<y> = kx.extension(Y^2 - x^5 -1)
> > > sage: kxy
> > > Function field in y defined by Y^2 - x^5 - 1
> > > sage: kxy.genus()
> > >
> ---------------------------------------------------------------------------
> > > AttributeError                            Traceback (most recent call
> > > last)
> >
> > > /home/syd/Documents/RecherchePhD/Codes/sage/GrbBasis/<ipython console>
> > > in <module>()
> >
> > > /home/syd/Programmes/sage-4.7.2/local/lib/python2.6/site-packages/sage/
> > > structure/parent.so in sage.structure.parent.Parent.__getattr__ (sage/
> > > structure/parent.c:6260)()
> >
> > > /home/syd/Programmes/sage-4.7.2/local/lib/python2.6/site-packages/sage/
> > > structure/parent.so in sage.structure.parent.getattr_from_other_class
> > > (sage/structure/parent.c:3110)()
> >
> > > AttributeError: 'FunctionField_polymod_with_category' object has no
> > > attribute 'genus'
> > > sage:
> >
> > > --
> > > To post to this group, send an email to sage-devel@googlegroups.com
> > > To unsubscribe from this group, send an email to
> sage-devel+unsubscr...@googlegroups.com
> > > For more options, visit this group athttp://
> groups.google.com/group/sage-devel
> > > URL:http://www.sagemath.org
> >
> > --
> > William Stein
> > Professor of Mathematics
> > University of Washingtonhttp://wstein.org
>
> --
> To post to this group, send an email to sage-devel@googlegroups.com
> To unsubscribe from this group, send an email to
> sage-devel+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/sage-devel
> URL: http://www.sagemath.org
>

-- 
To post to this group, send an email to sage-devel@googlegroups.com
To unsubscribe from this group, send an email to 
sage-devel+unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/sage-devel
URL: http://www.sagemath.org

Reply via email to