Hi,
I have a problem with draw() to do simple animations of the contents of
arrays in matplotlib.
I was trying to use the idea in the animations cookbook (
http://www.scipy.org/Cookbook/Matplotlib/Animations)
to animate some "random walkers", but found that the animation did not work.
A minimal example of the problem is given by changing the first recipe in
the cookbook to just draw random arrays.
This version correctly animates as expected:
from pylab import *
import time
ion()
tstart = time.time() # for profiling
x = rand(100)
y = rand(100)
line, = plot(x,y, ',')
for i in arange(1,200):
x = rand(100)
y = rand(100)
line.set_data(x,y)
draw() # redraw the canvas
Now, however, changing the "x =" and "y =" lines as follows:
x[:] = rand(100)
y[:] = rand(100)
so that they are modified in place, rather than creating new arrays, no
longer animates anything.
I am using version 0.99 on linux (Kubuntu 9.10).
The same behaviour is found from within ipython -pylab or from the command
line with python.
In my real application, I wish to use this as a simple way to animate a
collection of random walkers.
I thus have an array of positions which is updated at every step, and this
is what I want to animate,
which is the reason why I tried the array updating step above.
So far, my code is as follows:
from pylab import *
ion()
N = 1000
pos = zeros((N,2))
figure(figsize=(8,8))
points, = plot(pos[:,0], pos[:,1], ',')
axis([-20,20,-20,20])
for t in range(1000):
pos += uniform(-1,1,N*2).reshape(N,2)
points.set_data(pos[:,0].copy(), pos[:,1].copy())
draw()
The ".copy()" are an attempt at creating new arrays. Nonetheless, there is
no animation.
And if I put
points._x
in ipython, then it still has all zeros! Apparently the .set_data() hasn't
done anything.
Any help at getting this animation to work are greatly appreciated!
Thanks and best wishes,
David.
------------------------------------------------------------------------------
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
