Re: [Matplotlib-users] Memory problem using pylab.savefig() [bis]

[John H. <jdh...@ac...>]

>>>>> "aurelien" == aurelien gourrier <aur...@fr...> writes:

    aurelien> Dear all, I posted a message two days ago mentionning
    aurelien> memory problems while saving a large number of images,
    aurelien> which I guess was not so clear... I've worked a bit on
    aurelien> it and I think the questions seem clearer to me now. I
    aurelien> have paid particular attention to the threads in the
    aurelien> user mailing list dealing with memory problems.

What happens if you explicitly name the figure (ef figure(1)) 

for i in range(indEnd):

    figure(1)
    subplot(221)
    plot(ind, xx)

    subplot(222)
    X = rand(50,50)
    
    imshow(X)
    subplot(223)
    scatter(rand(50), rand(50))
    subplot(224)
    pcolor(10*rand(50,50))

    savefig('tmp%d' % i, dpi = 75)
    close(1)

See also the FAQ http://matplotlib.sourceforge.net/faq.html#LEAKS
which shows the canonical way to make multiple plots to prevent leaks,
namely, pairing a close with each figure creation?

I'm not sure why you are seeing a problem right now, but my memory
leak test script memleak_hawaii3.py does not appear to be leaking

#!/usr/bin/env python

import os, sys, time
import matplotlib
#matplotlib.interactive(True)
#matplotlib.use('Cairo')
matplotlib.use('Agg')
from pylab import *


def report_memory(i):
    pid = os.getpid()
    a2 = os.popen('ps -p %d -o rss,sz' % pid).readlines()
    print i, '  ', a2[1],
    return int(a2[1].split()[1])



# take a memory snapshot on indStart and compare it with indEnd

indStart, indEnd = 30, 201
for i in range(indEnd):

    figure(1); clf()

    subplot(221)
    t1 = arange(0.0, 2.0, 0.01)
    y = sin(2*pi*t1)
    plot(t1,y,'-')
    plot(t1, rand(len(t1)), 's', hold=True)


    subplot(222)
    X = rand(50,50)

    imshow(X)
    subplot(223)
    scatter(rand(50), rand(50), s=100*rand(50), c=rand(50))
    subplot(224)
    pcolor(10*rand(50,50))
    savefig('tmp%d' % i, dpi = 75)
    close(1)

    val = report_memory(i)
    if i==indStart: start = val # wait a few cycles for memory usage to stabilize

end = val
print 'Average memory consumed per loop: %1.4fk bytes\n' % ((end-start)/float(indEnd-indStart))