Re: [Matplotlib-users] segfaults in ipython, mpl verbose

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

>>>>> "Steve" == Steve Schmerler <el...@gm...> writes:

    Steve> Hi Ups I think I missunderstood the meaning of VERBOSE =
    Steve> True in setup.py when compiling.

    Steve> When I start ipython -pylab and try to plot mpl prints a
    Steve> lot of mesages and _these_ are the ones of interest, sorry.

    Steve> OK here is the output of some tests:
...
    Steve> This was with GTKAgg. The same happens with Agg, TkAgg,
    Steve> GTK.

    Steve> This bug really annoys me by now and I'm wondering why mpl
    Steve> 0.82 installed as Debian package works.

Steve,

Thanks for the  patient tests.  I am taking this offlist so we don't annoy
everyone with too much mail on this subject, but am CC-ing the parties
who might have additional insight.

It is interesting that it happens both on Agg and non-Agg backends --
that narrows things down a bit.  It is also most interesting that it
only happens when you run as a normal user and not root.  The VERBOSE
output you posted suggests the problem is not occurring inside a mpl
extension code function, since it ends with "RendererAgg::draw_polygon
DONE"

I'm about out of suggestions sadly, but do have one more request

  Compile 0.82 from src.  Since that version is working in the debian
  build, it would be interesting to see if it works when *you* build
  it.  Ie, is there something wrong with matplotlib, or something
  wrong with your build environment.

  Also, how do you compile matplotlib, as a normal user or as root?
  If you are compiling and installing as root, may I suggests
  installing sudo (apt-get install sudo) and adding yourself to
  /etc/sudoers.  Then compile matplotlib as a normal user and install
  with sudo

  > python setup.py build
  > sudo python setup.py install

  Or is this the way you are already doing it.

As always, before anything else, sudo rm -rf site-packages/matplotlib
and the build dir of your matplotlib src tree.

One other thing that would be helpful, you can start inserting debug
print statements in lib/matplotlib/pylab.py

print "ich bin hier 1"
skip 20 lines
print "ich bin hier 2"
skip 20 lines
print "ich bin hier 3"

and try and figure out exactly where in the module the failure occurs
(it could also be in lib/matplotlib/__init__.py).  Once you have the
crash narrowed down between two lines, you can add more print
statements further subdivide it and triangulate down to the true evil
line.  If we could at least figure out which part of the code is
triggering the failure, it might help diagnose and fix it.  This can
be tedious, but is sometimes the best way to resolve these problems.

JDH