On Nov 25, 2007 4:29 PM, William Stein <[EMAIL PROTECTED]> wrote:
>
>
> On Nov 25, 2007 3:27 AM, Martin Albrecht <[EMAIL PROTECTED]> wrote:
> >
> > > @Martin Albrecht:
> > > - Is there a reasonable way to fix this in the interface?
> >
> > Hi, the 'trivial' way to fix it, is to implement a Python function for
> > SinguleElement called invariant_ring which calls the Singular function,
> > parses the output and returns a tuple. If you call A.invariant_ring the
> > Singular function is only called directly if there is no Python function
> > with
> > the same name.
> >
> > A better - and I guess doable - approach is to track down why it fails and
> > fix
> > it.
> >
> > > - If not: What could we do on the side of Singular to make the return
> > > of a tuple (like return(P,S,IS)) comprehensible for the interface? I
> > > guess "return(list(P,S,IS))" would work, but i'm not sure if this
> > > change of syntax wouldn't have nasty consequences for existing
> > > applications.
> > >
> > > There is a very clumsy way to pull the output of invariant_ring into
> > > sage:
> > > First, define A and R as above. Then say
> > > singular.eval('matrix P,S,IS=invariant_ring(%s)'%(A.name()))
> > > P=singular('P')
> > > S=singular('S')
> > > IS=singular('IS')
> > >
> > > But definitely i do think the correct syntax should be
> > > P,S,IS=A.invariant_ring()
> >
> > and this is definitely possible either by doing what you are doing above
> > within a Python wrapper function or by fixing that issue.
> >
> > > Now, another question on the Singular interface:
> > > In Singular, doing
> > > matrix P,S,IS = invariant_ring(A,1);
> > > would make Singular to additionally print information about the
> > > progress of computations (which, in big examples, might be nice to
> > > have).
> > >
> > > However, when i use the Singular interface, i can not see such
> > > informations. Where are they gone?
> >
> > The information is printed but ignored because pexpect expects
> > Singular 'output' and ignores the rest. I am no pexpect expert so I don't
> > know how to fix it. It would very very useful though. Anyone else has any
> > idea?
>
> I think this would be possible to implement, by modifying
> interfaces/singular.py.
> Please open a trac ticket. It's easiest if we just have it print out
Done:
http://sagetrac.org/sage_trac/ticket/1274
I'll open one up regarding the original question (about invariant rings)
when I've thought about it more. Hopefully Tuesday sometime.
> the result of
> all the verbose output, rather than all of it along the way as it is
> output by singular,
> though the latter would also be possible. With pseudo-tty's it is
> possible to do
> anything you could really imagine doing by hand while physically using
> a terminal
> to interact with singular. Anything.
>
> -- William
>
>
> >
>
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