Arch Linux

goodgrue

Member

From: CA, USA

Registered: 2008-11-19

Posts: 41

ipython -pylab no longer interactive (confirmed: upstream bug)

I just did a pacman -Syu that involved the big python upgrade.  As part of the upgrade I reinstalled matplotlib and I also deleted the .matplotlib/fontList.cache that causes problems.  Everything seemed to work great except now when I run "ipython -pylab", ipython doesn't seem to start a separate thread for GUI stuff.  I get the following behavior:

ipython -pylab

Python 2.7 (r27:82500, Oct  6 2010, 12:18:19) 
Type "copyright", "credits" or "license" for more information.

IPython 0.10.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

  Welcome to pylab, a matplotlib-based Python environment.
  For more information, type 'help(pylab)'.

[~]
|1>plot([0,1], [0,1])
[1] [<matplotlib.lines.Line2D object at 0x92cd22c>]

I can use show() to see the plot, but then I'm stuck in gtk.main().

I have no idea how to troubleshoot this as there is no actual error message.  Anyone else experiencing this or have suggestions?

Update: I have one 32-bit and one 64-bit Arch machine, and this issue is present on both of them.
Update2: It would also be nice to hear if there is at least one person with an up-to-date system not having this issue.
Update3: I've done some tests trying to set up an interactive matplotlib environment manually, with interesting results.  I've played with both ipython (without -pylab) and the standard python shell, and used the following sequence of commands:

import matplotlib
matplotlib.use('gtkagg') # (or 'tkagg')
from matplotlib.pylab import *
ion()
figure()

The standard python shell worked perfectly with both tkagg and gtkagg (a figure window opened and control returned to the shell).  With ipython, the tkagg backend worked, but gtkagg did not (it produced the same behavior I see with ipython -pylab.
Update4: Okay, turns out this is a bug in ipython and there is a report here: http://github.com/ipython/ipython/issues/issue/185 .  Hopefully it will be fixed soon .

Last edited by goodgrue (2010-10-26 07:07:53)