Re: [Visualpython-users] How to plot only 'the last N points' using gcurve

[Gary <pa...@in...>]

Hans Fangohr wrote:

> Dear all, I am trying to use gcurve to continuously display the last N
> points of a scalar function. More concrete: a simulation goes through
> a number of iterations and for each iteration, I'd like to plot one
> scalar value. I want to display the last N points using gcurve.

I'm not exactly sure what you are trying to achieve, but I have 
something that seems similar.

I wanted a stripchart...  somthing that displays the latest data, while 
the older data falls off of the other end.   Pmw.Blt has a stripchart.  
So I married Pmw.Blt and Vpython.   An early demo is here: 

http://enigma.rider.edu/~gpajer/python.htm

(IT is warning us that this server may disappear soon ... so don't 
delay!)  since then I've spruced it up a bit, but this example displays 
various little features.  The code is a bit hard to read ... sorry about 
that.

It is also possible to make a stripchart using matplotlib 
(matplotlib.sf.net) .   It's much slower (see below). 

Blt seems no longer supported or developed, but it works.  A shame ... 
it has some nice features.  For some reason, it is hard to install.  I 
can attest that Pmw.Blt *does* work on Windows,  OS X,  and Linux.   
Windows instructions are on my weblink above.  On OS X, it installs and 
runs readily using fink.  Because of a bug in the configure script, 
Linux requires an environment variable ... can't recall it right now.  
I'll get it later if anyone wants it.


[commercial break:  nothing against matplotlib!!!  I find that the 
combination of ipython/scipy/matplotlib/Vpython  plus the non-pythonic 
Maxima makes a powerhouse of a scientific package.  More functionality 
than Matlab or Mathematica at none of the price.  And better support :)   ]

-gary