[Matplotlib-users] Memory leak with pcolor

[Alexander M. <ale...@co...>]

Thanks for your advice with installing matplotlib on cygwin. I =
downloaded and installed the windows binaries and it worked.

Anyway, the reason that I didn't want to use binaries in the first place =
was because I wanted to modify the matplotilb source code. But it seems =
like even with the binaries, if I change the source code then it will =
still affect the operation of the program when I run it, which is what I =
want.

In particular, I am looking to speed up the pcolor() function because it =
runs exceedingly slow with large mesh sizes. I believe the reason it is =
running slow is because of a memory leak. When I do the following:

from pylab import *
n=3D200
[x,y]=3Dmeshgrid(arange(n+1)*1./n,arange(n+1)*1./n)
z=3Dsin(x**2 + y**2)

and then do

pcolor(x,y,z)

repeatedly, the memory usage increases by about 15 MB each time, and it =
runs progressively slower.each time. By using the profiler I can see =
that almost all the time is spent in the pcolor function itself, rather =
than any functions it calls. When I take out the line =
"self.add_collection(collection)", there is no memory leak and it runs =
much faster (of course, since I'm not actually adding the collection on, =
when I do that i can no longer actually see the plot). It seems to me =
like what is happening is that it is repeatedly appending the same =
PolyCollection to the collections list, using up more and more memory. =
What I want to know is what the "collections" are and how they are used =
so I can figure out a way of getting rid of extraneous collections.

-Alexander Mont