sorry, i replied to Mike and not to the list. see below.
On Thu, Jul 2, 2009 at 2:57 PM, Ralf Gommers <ralf.gomm...@googlemail.com>wrote: > Thanks for looking into this Mike. > > On Thu, Jul 2, 2009 at 10:39 AM, Michael Droettboom <md...@stsci.edu>wrote: > >> It is not surprising that memory usage is much lower without printing the >> plot. Very little is actually done by the "plot" command other than setting >> up a tree of objects that is later rendered during the printing process >> (where most of the work happens). >> >> The attached script based on what you provided doesn't leak memory for me >> with matplotlib 0.98.5.2. It would appear that there is something else in >> your application triggering the leak. Perhaps there is something holding a >> reference longer than it should? >> > > Your attached script memleak2.py is indeed fine, it never takes up more > than 60Mb of RAM. But did you try to run the PyQt4 GUI I attached? There > the same save_png() function does increase memory usage for each call. > > I'm not sure how to exactly measure memory usage for a GUI program, but it > is so large I can look at "System Activity" (or Task Manager on XP) and get > the approximate number: > > Loading the GUI: 30.5Mb > 1st call to save_png: 82Mb > 2nd call: 116Mb > 10th call: 380Mb > > I can see the memory usage drop after some calls, so I guess it is a > problem of references being held and sometimes being released as you said. > But memory use does seem to be unbounded. Waiting for minutes, or > interacting with the GUI, never releases any memory. It is strange, the > PyQt4 demo program is fine by itself, save_png() is fine by itself, but > combine them and there's a memory problem. > > Cheers, > Ralf > > > >> You can see from the attached massif plots that memory usage never becomes >> unbounded. It is normal for Python to delay deallocation for efficiency >> reasons. Calling gc.collect (the second graph) does help keep memory usage >> more compact however, if that is a primary concern. >> >> Cheers, >> Mike >> >> Ralf Gommers wrote: >> >>> Hi, >>> >>> I am working on a PyQt4 application with some embedded MPL figures, and >>> am also trying to save some figures as png's without displaying them. I am >>> observing huge memory increases (10s or 100s of Mb) the moment I try to save >>> a png. I reproduced the issue by combining two mpl examples, >>> http://matplotlib.sourceforge.net/examples/user_interfaces/embedding_in_qt4.htmland >>> http://matplotlib.sourceforge.net/examples/api/agg_oo.html. Full code is >>> attached. When pressing the "save figure" button, memory usage shoots up, >>> multiple clicks keep sending it higher (although not monotonically). >>> >>> I tested on two different platforms >>> - Matplotlib 98.5.2 and Python 2.6.2 on Ubuntu. >>> - latest Enthought Python Distribution on Windows XP. >>> >>> The function that does the png saving is: >>> >>> def save_png(): >>> """Save an image as a png file""" >>> >>> pngpath = 'test_mplsave.png' >>> >>> fig = Figure() >>> canvas = FigureCanvas(fig) >>> ax = fig.add_subplot(111) >>> x = arange(5e3) >>> ax.plot(x, sin(x)) >>> canvas.print_figure(pngpath) >>> >>> ## tried all things commented out below, all makes no difference ## >>> #fig.savefig(pngpath) >>> >>> #del(fig) >>> #del(canvas) >>> #del(ax) >>> >>> #import matplotlib.pyplot as plt >>> #plt.close(fig) >>> >>> #import gc >>> #gc.collect() >>> >>> Commenting out the canvas.print_figure line fixes the issue. >>> >>> Am I doing something obviously wrong, or mixing two incompatible ways of >>> doing things? >>> >>> Cheers, >>> Ralf >>> >>> ------------------------------------------------------------------------ >>> >>> >>> ------------------------------------------------------------------------------ >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >> >> -- >> Michael Droettboom >> Science Software Branch >> Operations and Engineering Division >> Space Telescope Science Institute >> Operated by AURA for NASA >> >> >> from matplotlib.backends.backend_agg import FigureCanvasAgg as >> FigureCanvas >> from matplotlib.figure import Figure >> >> from numpy import arange, sin >> >> import gc >> >> def save_png(): >> """Save an image as a png file""" >> >> pngpath = 'test_mplsave.png' >> >> fig = Figure() >> canvas = FigureCanvas(fig) >> ax = fig.add_subplot(111) >> x = arange(5e3) >> ax.plot(x, sin(x)) >> canvas.print_figure(pngpath) >> >> # The below is not necessary to prevent a leak, but it does make >> # memory usage more compact >> gc.collect() >> >> for i in range(100): >> save_png() >> >> >> >> >
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