> Let me know if you have trouble.  I haven't used view much in the last year
> (I use the notebook more), so it might be somehow broken (??), as its
> hard to automatically test.

I only tried the 2.4 binary version on debian unstable and it works
nice. Thanks. That's what I am going to do in sympy - to launch an
external program, so that it doesn't block the command line. And the
notebook is very nice. The tab completion, that works at sagenb.com
didn't work for me locally (it printed a tab instead) - is it a bug?
I would expect it to work according to the documentation:
http://modular.math.washington.edu/sage/doc/html/ref/node19.html

But I myself prefer to work in my own python script in vim and execute
it in python using F10.

> That sympy depends on pygame is painful, since pygame isn't
> trivial to install.  When somebody recently was installing sympy
> into SAGE, they biggest issue was first installing pygame into SAGE
> (they did it, but it wasn't completely trivial).

That is a bug, sympy shouldn't depend on anything besides a pure
python (2.4) installation. You should have written to the sympy
mailinglist, we would fix that. I think it is already fixed now, but
we'd better check it again.

> SAGE makes no nontrivial use of either mathml or openmath.
>
> For latex output, all SAGE objects have an  _latex_ method, sort
> of like Python's __repr__ method; every object can thus output
> itself in latex format directly -- there is no mathml intermediate.
> Likewise, to export an object to maxima, every SAGE object
> has a _maxima_init_ method that outputs a string that, when
> interpreted by Maxima, gives a corresponding object.  Also,
> objects have a _maxima_ method that takes an instance of
> maxima and returns a Python classes of type MaximaElement
> that is a pointer to an actual object in a running instance
> of Maxima (and that object is cached, so subsequent calls
> return the same object -- moreover if the maxima session crashes
> the object is automatically recreated).    All the statements above
> about maxima apply to the other dozen or so SAGE interfaces, e.g.,
> to Maple, Magma, GAP, Singular, etc.  (there are defaults for
> the various .._init_ methods in the base class...).
>
> To convert an arbitrary symbolic expression as output by maxima back to
> SAGE there is a function (new in SAGE-2.5) that sets up some variables,
> does some minimal preparsing, then uses Python's eval command on
> a string.  Thus the conversion from maxima to Python is:
>
>   maxima string repr --> slightly parsed version
>             --> Python interpreter's eval --> Python object
>
> We have not written something like this (that works in general) for
> Maple or Mathematica yet, but Bobby Moretti is working on it right now.

Thanks for the explanation. That's how it was originally in SymPy,
that every class (like sin, cos, Mul) can export itself to
latex/python/ascii art/etc., but the code was becoming quite cluttered
with this printing stuff, so we decided to export only mathml and we
added optional modules to convert it from mathml (which seemed to us
as a standard) to any other format. But I am actually not 100%
convinced that the mathml way is optimal - because the xsl stylesheets
are really ugly.

And as to porting SymPy to SAGE - I wouldn't suggest to do it right
now, as currently SymPy is evolving too fast. But I guess at the end
of the summer it should be quite equipped with most things and the
interface will probably settle down. But I guess your calculus package
will be able to do the same things through maxima, so there will be no
need for porting SymPy anyway I think. Only if it turns out, that the
hybrid python+maxima is impossible to extend with new algorithms (for
limits, or integration, or differential equations, that maxima cannot
handle).

Ondrej

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