[matplotlib-devel] merging sympy plotting stuff with matplotlib

Resending, the first try doesn't seem to make it to the list.


---------- Forwarded message ----------
From: Ondrej Certik <on...@ce...>
Date: Dec 30, 2007 7:33 PM
Subject: merging sympy plotting stuff with matplotlib
To: mat...@li...


Hi matplotlib developers,

we are developing a symbolic manipulation library in pure Python:

http://code.google.com/p/sympy/

and we wanted to do 3D plotting. To make a long story short, here is a
tutorial for our 3D plotting stuff:

http://code.google.com/p/sympy/wiki/PlottingModule

here is a reasoning behind all of this:

http://code.google.com/p/sympy/wiki/PlottingReport

especially this:

http://straightupcoding.blogspot.com/2007/05/case-for-dropping-matplotlib.html


We should have gotten involved more in matplotlib development earlier,
but at least now. I think there should be just one 3D plotting
library in Python and imho matplotlib should do it. However, we need:

* it should be pure python
* fast and interactive 3D stuff
* needs to work out of the box on linux, mac os x, windows (without compilation)

you can read all details above, but we simply use pyglet
(http://pyglet.org/), that is like pygame, but better (pure python,
works out of the box on all platforms etc).

Are you interested in getting our 3D stuff into matplotlib?

If yes, is there a way to make matplotlib pure python?

Looking at matplotlib sources, the only things done in C++ are agg
backend, and then the src/* directory, which I am not sure what
exactly it's doing, but I don't see a reason why the kernel of
matplotlib cannot be in pure Python (calling python gtk etc.).
Optionally, there can be the C++ modules.

If such a division is possible, then we could just include matplotlib
in sympy sources, the license of matplotlib seems quite permissive:

http://matplotlib.sourceforge.net/license.html

so it should allow this (sympy and pyglet is BSD). In distributions,
like Debian, sympy will just depend on matplotlib in debian. But the
sympy tarball should be self-contained.

The sympy plotting is quite nice, especially that you just download
the tarball and it works (even on windows, or macosx) without
compilation, however it's missing a lot of features that matplotlib
has, so the best thing to do is to integrate it in matplotlib.

Another cool stuff in matplotlib is the pure python latex renderer
(/matplotlib-0.91.1/lib/matplotlib/mathtext.py). See our issue for
more info:

http://code.google.com/p/sympy/issues/detail?id=506

we want to use it in our preview capability (currently only in our hg repo):

$ hg clone http://hg.sympy.org/sympy/
$ cd sympy
$ bin/isympy
[...]
In [1]: from sympy.abc import *

In [2]: pngview(Integral(exp(-(tau-mu)**2/2/sigma**2), (tau, -oo, oo))/
   ...: sigma/sqrt(2*pi))

And a window will popup (using pyglet) showing a nice latex printed
expression. Currently, you need to have latex installed (and
python-pexpect)
for it to be working. (if you use sympy hg right now, you need
python-pexpect, but we'll fix this before we release soon:
http://code.google.com/p/sympy/issues/detail?id=520, any sympy tarball
only needs pure Python 2.4 or newer and it will just work, otherwise
it's a bug)

So it'd be cool to you your pure python reimplementation of the tex
engine. Maybe let's create a new (standalone) project just for this
feature? I am sure
it will benefit to a lot of people. And sympy and matplotlib will just
include it in the sources.

If you have any other ideas regarding these issues, we are interested.

Looking for collaboration,
Ondrej