matplotlib-devel

[matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[Neal B. <ndb...@gm...>]

I'm getting these messages, which did not occur with 1.1:

Traceback (most recent call last):
  File "/home/nbecker/.local/lib/python2.7/site-
packages/matplotlib/backends/backend_qt4.py", line 151, in <lambda>
    lambda: self.close_event())
  File "/home/nbecker/.local/lib/python2.7/site-
packages/matplotlib/backend_bases.py", line 1564, in close_event
    self.callbacks.process(s, event)
RuntimeError: underlying C/C++ object has been deleted

Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[Michael D. <md...@st...>]

Can you provide more detail about how to reproduce this?

I can deduce you're using the Qt4Agg backend -- but running 
simple_plot.py, zooming around, and then closing the window does not 
seem to reproduce the error here.

What version of Qt/PyQt/PySide are you running.  What platform?

Mike

On 03/28/2012 08:34 AM, Neal Becker wrote:
> I'm getting these messages, which did not occur with 1.1:
>
> Traceback (most recent call last):
>    File "/home/nbecker/.local/lib/python2.7/site-
> packages/matplotlib/backends/backend_qt4.py", line 151, in<lambda>
>      lambda: self.close_event())
>    File "/home/nbecker/.local/lib/python2.7/site-
> packages/matplotlib/backend_bases.py", line 1564, in close_event
>      self.callbacks.process(s, event)
> RuntimeError: underlying C/C++ object has been deleted
>
>
> ------------------------------------------------------------------------------
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Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[Neal B. <ndb...@gm...>]

qt-x11-4.8.0-7.fc16.x86_64
PyQt4-4.8.6-1.fc16.x86_64

But interestingly, I'm not actually using the display in this script.  I'm using 
pdfpages.

The basic outline is:
At the start:

        from matplotlib.backends.backend_pdf import PdfPages
        self.pdf = PdfPages(file_name)

Then at the start of each page I do:
        self.prop = mpl.font_manager.FontProperties(size='xx-small')

        self.fig = fig = plt.figure() 
        self.ax = fig.add_subplot(111)
        fig.subplots_adjust(bottom=0.2)
        self.colors = itertools.cycle(['r','g','b','c','y','m','k']) 
        self.markers = itertools.cycle(['o','s','v']) 

Then at the start of each plot on a page I do:
        
	self.ax.semilogy (esno, [e for e in per], c=self.colors.next(), 
marker=self.markers.next(), label='iter=%s'%n_iter)

Finally, to finish each page:

        plt.title (...)
        plt.grid(which='major', linestyle='solid')
        plt.grid(which='minor', linestyle='dashed')
        plt.legend(prop=self.prop, loc='best')
        self.ax.set_xlabel ('${E_s}/N_0$')
        self.ax.set_ylabel ('per')
        plt.figtext (0, 0, res['carriers'].values, horizontalalignment='left', 
verticalalignment='bottom', size=5)
        self.pdf.savefig (self.fig)
        plt.close()

Then when all pages are done:
        self.pdf.close()

It looks like I'm getting one of these error messages for each page.


Michael Droettboom wrote:

> Can you provide more detail about how to reproduce this?
> 
> I can deduce you're using the Qt4Agg backend -- but running
> simple_plot.py, zooming around, and then closing the window does not
> seem to reproduce the error here.
> 
> What version of Qt/PyQt/PySide are you running.  What platform?
> 
> Mike
> 
> On 03/28/2012 08:34 AM, Neal Becker wrote:
>> I'm getting these messages, which did not occur with 1.1:
>>
>> Traceback (most recent call last):
>>    File "/home/nbecker/.local/lib/python2.7/site-
>> packages/matplotlib/backends/backend_qt4.py", line 151, in<lambda>
>>      lambda: self.close_event())
>>    File "/home/nbecker/.local/lib/python2.7/site-
>> packages/matplotlib/backend_bases.py", line 1564, in close_event
>>      self.callbacks.process(s, event)
>> RuntimeError: underlying C/C++ object has been deleted
>>
>>
>> 
------------------------------------------------------------------------------
>> This SF email is sponsosred by:
>> Try Windows Azure free for 90 days Click Here
>> http://p.sf.net/sfu/sfd2d-msazure
>> _______________________________________________
>> Matplotlib-devel mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
> 
> 
> ------------------------------------------------------------------------------
> This SF email is sponsosred by:
> Try Windows Azure free for 90 days Click Here
> http://p.sf.net/sfu/sfd2d-msazure

Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[John H. <jd...@gm...>]

On Wed, Mar 28, 2012 at 8:57 AM, Neal Becker <ndb...@gm...> wrote:

> qt-x11-4.8.0-7.fc16.x86_64
> PyQt4-4.8.6-1.fc16.x86_64
>
> But interestingly, I'm not actually using the display in this script.  I'm
> using
> pdfpages.


At the beginning of your script (before importing pylab/pyplot) you should
be doing

import matplotlib
matplotlib.use('pdf')

It looks like you are inadvertently importing the qt library in a headless
script run.

JDH

Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[Neal B. <ndb...@gm...>]

John Hunter wrote:

> On Wed, Mar 28, 2012 at 8:57 AM, Neal Becker
> <ndb...@gm...> wrote:
> 
>> qt-x11-4.8.0-7.fc16.x86_64
>> PyQt4-4.8.6-1.fc16.x86_64
>>
>> But interestingly, I'm not actually using the display in this script.  I'm
>> using
>> pdfpages.
> 
> 
> At the beginning of your script (before importing pylab/pyplot) you should
> be doing
> 
> import matplotlib
> matplotlib.use('pdf')
> 
> It looks like you are inadvertently importing the qt library in a headless
> script run.
> 
> JDH

Thanks, but should that cause a (scary looking) error?  Or is there a real 
problem?

Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[John H. <jd...@gm...>]

On Wed, Mar 28, 2012 at 1:22 PM, Neal Becker <ndb...@gm...> wrote:

>
> > import matplotlib
> > matplotlib.use('pdf')
> >
> > It looks like you are inadvertently importing the qt library in a
> headless
> > script run.
> >
> > JDH
>
> Thanks, but should that cause a (scary looking) error?  Or is there a real
> problem?
>
>
> It's just a clean up error in the qt destructors I  think.  You are
basically in an unsupported use case: using a gui backend, but not raising
the figures with show, so our initialization code doesn't get run properly,
which means the clean up may not be properly configured.  Our work is hard
enough supporting all the GUI toolkits across multiple operating systems --
I don't know that we want to get into trying to support *unsupported* use
cases.

JDH

Re: [matplotlib-devel] 1.1.1rc RuntimeError: underlying C/C++ object has been deleted

[Benjamin R. <ben...@ou...>]

On Wed, Mar 28, 2012 at 2:36 PM, John Hunter <jd...@gm...> wrote:

>
>
> On Wed, Mar 28, 2012 at 1:22 PM, Neal Becker <ndb...@gm...> wrote:
>
>>
>> > import matplotlib
>> > matplotlib.use('pdf')
>> >
>> > It looks like you are inadvertently importing the qt library in a
>> headless
>> > script run.
>> >
>> > JDH
>>
>> Thanks, but should that cause a (scary looking) error?  Or is there a real
>> problem?
>>
>>
>> It's just a clean up error in the qt destructors I  think.  You are
> basically in an unsupported use case: using a gui backend, but not raising
> the figures with show, so our initialization code doesn't get run properly,
> which means the clean up may not be properly configured.  Our work is hard
> enough supporting all the GUI toolkits across multiple operating systems --
> I don't know that we want to get into trying to support *unsupported* use
> cases.
>
> JDH
>
>
True that this is probably an unsupported use-case, but I don't see it as a
totally unreasonable one.  For example, in many of my scripts in one of my
projects, I have command-line options to determine if I am going to save
the figure to a file and another option to determine if I am going to show
the figure as well.  I could run these scripts with or without showing a
figure.  By the time I process the command-line arguments, I have already
imported matplotlib.  Of course, it isn't very difficult to recode it to
import and select a backend according to the command-line arguments, it
would be a more convoluted script that way.

Note, I have not noticed any issues with this approach while using TkAgg
and GTKAgg.  I guess it could probably be made into a low-priority TODO
item in PyQt4 to see if the destructor is being over-zealous.  Neal, your
best bet would be to file a wishlist item and tag it as such.  Again, low
priority, but maybe someone will notice something obvious at a later time.

Cheers!
Ben Root