On Fri, Sep 19, 2008 at 6:10 PM, Jason Merrill <[EMAIL PROTECTED]> wrote:
>
> On Sep 18, 2:09 pm, Burcin Erocal <[EMAIL PROTECTED]> wrote:
>> On Thu, 18 Sep 2008 06:57:20 -0700 (PDT)
>>
>> Jason Merrill <[EMAIL PROTECTED]> wrote:
>>
>> > On Sep 18, 8:01 am, Burcin Erocal <[EMAIL PROTECTED]> wrote:
>> <snip>
>> > > Did you manage to build the pynac package? If not, I can post a
>> > > modified version which should build in your environment so you can
>> > > start playing with the new code.
>>
>> > I am now able to install the spkg if I take macports off my path
>> > (which I also had to do to build 3.1.2.rc2). Trying to apply the
>> > patch athttp://trac.sagemath.org/sage_trac/ticket/3872, though,
>> > causes a conflict. Any chance there could be an updated patch
>> > sometime soon that takes into account all the changes that went into
>> > 3.1.2?
>>
>> You can use the bundle here:
>>
>> http://www.risc.jku.at/people/berocal/sage/pynac.hg
>
> Hi Burcin,
>
> I was able to apply the above patch cleanly, and I now have a working
> version of the new symbolic ring to play with. Thanks!
>
> I'd like to have a better understanding of the status of pynac, and
> what it means for working on Sage in the coming weeks. Now that I can
> play with pynac, who should I tell about my experience, and what sorts
> of things are useful to share? Pynac as it stands seems far from
> feature complete, but I'm sure you already know that.
Yes. It is very very very far from "feature complete". In fact, we view
it as an absolutely minimal implementation of just enough to be useful
to start a second stage of development.
> For instance,
>
> sage: x = var('x',ns=1)
>
> sage: type(x)
> <type 'sage.symbolic.expression.Expression'>
>
> # No plotting, I assume most other numerical operations
> # don't work for similar reasons
> sage: plot(x^3,-3,3)
> verbose 0 (3585: plot.py, _plot) WARNING: When plotting, failed to
> evaluate function at 400 points.
> verbose 0 (3585: plot.py, _plot) Last error message:
> ''sage.symbolic.expression.Expression' object is not callable'
>
> # Making a callable symbolic function involving x actually
> # changes x back to the old symbolic ring
> sage: g(x) = x^3
> sage: type(x)
> <class 'sage.calculus.calculus.SymbolicVariable'>
>
> Somehow I doubt a flood of bug reports like these would be useful
> right now.
Yes, that would be useless.
> But at the same time, William suggests that writing code
> specific to the current calculus module is now pointless. So what is
> the best use of time currently? Waiting? For how long?
Yes. I'm sorry, but unfortunately this is how software development
sometimes works. It's painful. It has been very bad already because
another developer put a "lock" on symbolic calculus stuff in January 2008, and
in August had made worrisome progress. Yes, this is happening again
now, but hopefully Burcin/my progress will be much faster.
You could also help with the work to make the pynac based symbolic
calculus in sage feature complete.
> I'm really grateful to Burcin and William for taking the time and
> initiative to write this new code. Because of your leadership and
> hard work, symbolics in Sage looks to have a bright future. But at
> least to me, it has a hazy present.
I hope the above statements clarify the situation. You could also
look at the todo file in the
SAGE_ROOT/devel/sage/sage/symbolic
directory.
William
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