On 4/22/07, Ondrej Certik <[EMAIL PROTECTED]> wrote:
> > If tab completion doesn't work for you locally there is some sort of bug
> > somewhere. Though there are no known (by me) bugs that would cause
> > that problem.
>
> I was trying it in Epiphany, so that was probably it (unless I did
> something wrong), because I just tried firefox and it works great.
Thanks for the report. We really need to add a visible warning when
a person uses a non-supported browser. Implementing javascript
tab completion in a web browser textarea was quite tricky -- Tom Boothby
finally figured out how to do it -- the main trick involves figuring out
where the cursor is by copying all text up to the cursor and seeing how
many characters there are (!).
> > Cool -- I'm glad it's easy to install. I assume it also works fine with
> > Python 2.5. Anyway, let me know when you guys have a new stable
> > ready version, and I can make it an optional SAGE package, so it's
> > trivial for any SAGE users to install sympy.
>
> ...
>
> > It is extendable with new algorithms. It's just that the approach of
> > making a hybrid python + maxima system gives us a CAS that is
> > very powerful and full featured _today_ while minimizing the need
> > to re-implement basic algorithms, at least until there is sufficient
> > energy and funding to do so. It's not inconceivable that slowly but
> > surely in the future many things in the SAGE CAS functionality that
> > rely on Maxima right now will instead rely on either native Python
> > code (e.g., via sympy), compiled SageX code, or something else
> > (e.g., yacas, ginac, etc.). It's an iterative process.
>
> I see. You are right, when we release the 0.4 in couple of weeks, I'll
> try to create a SAGE package with your help, because that would allow
It will be very easy to create a SAGE package. All you do is create a directory
with sympy in it and a setup.py, just like you have already. Then, if the
directory is called sympy-0.4 you do
sage -pkg sympy-0.4
from the directory that contains the sympy-0.4 directory. This will result
in a SAGE package sympy-0.4.spkg, which can be installed by typing
sage -i sympy-0.4.spkg
Probably nothing else will be required.
> easy comparisons with other CASes. Of course there is no need to
> reimplement anything, that Maxima can do. What I don't like on them is
> their interface. So I am looking forward to your sage.calculus, that
> actually can make Maxima quite usable.
>
> As to the extensibility - I think it would be quite difficult to
> extend for example Maxima's limits facility (there are some limits
> that Maxima cannot do, but SymPy can), or Maxima's differential
> equations solver module. Either it would have to be done in LISP, or
> rewrite the whole module to python, neither of which I find easy. Or
> is there a better approach?
I had in mind the following iterative approach:
(1) Implement the basic limit formulas for products, sums, quotients, etc.,
in Python.
(2) This reduces computing limits of symbolic expressions to computing
the limits of the leaves in the tree, i.e., symbolic
variables, constants, and
primitive functions (like sinh, exp, log, erf).
(3) Limits of symbolic variables and constants are trivial.
(4) For some special functions one writes an optional method _limit_
that computes the limit of that special function at a point from a given
direction. The default _limit_ method in the base class computes the
limit using maxima. So for each function for which you want better
speed or a different behavior from maxima, you just fill in the
_limit_ method.
Exactly the steps above would also work for symbolic differentiation.
(Integration is a completely different story.)
--
William Stein
Associate Professor of Mathematics
University of Washington
http://www.williamstein.org
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