Cannot plot inline in IPython console on Linux

[petebachant]

Using 2.3.3 with Python 3.4.3 installed via Conda. Attempting to plot via matplotlib inline in the IPython console kills the kernel. I am not having this problem on Windows.

[blink1073]

I can confirm:

%matplotlib inline

import matplotlib.pyplot as plt

plt.plot([1,2,3])
Out[3]: [<matplotlib.lines.Line2D at 0x7fc1e46c5f60>]
It seems the kernel died unexpectedly. Use 'Restart kernel' to continue using this console.

[blink1073]

Works fine with Py2.7.

[blink1073]

...and it works fine from a standalone IPython QtConsole with Py3.4.

[blink1073]

I used IPython 3.0.0 in both cases.

[ccordoba12]

I was about to release 2.3.4 tomorrow but this seems pretty serious.

I can't reproduce it on my end with pip installed mpl 1.4.3 and Python 3.4.0. It seems to be an issue with mpl or Anaconda or both.

Edit: I'm also using IPython 3.0

[ccordoba12]

Is %matplotlib qt working for you?

[petebachant]

%matplotlib qt does work for me.

[blink1073]

Also for me.

[ccordoba12]

What about mpl 1.4.2 and/or Python 3.4.2?

[petebachant]

Tried both (one at a time) and kernel is still dying.

[blink1073]

Ditto.

[ccordoba12]

@stonebig, have you seen this problem on WinPython?

This really seems a compilation bug to me. I don't understand what we can be doing to make the kernel crash.

What if you try to use 2.3.4dev or 2.4dev? I made some commits to change how we set the mpl backend that could help in this case...

[ccordoba12]

Checking older Spyder versions (in the 2.3 series) would be useful too :-)

[petebachant]

Works fine in 2.3.2.

[ccordoba12]

@petebachant, great, some progress!! Could you use git bisect to detect the faulty commit?

[petebachant]

I don't know how to do that; sorry! I did, however get the console to plot SVGs, and noticed this commit: ac52a4a. Maybe the dpi for PNGs is being set incorrectly?

[petebachant]

I just noticed that spinbox does not work in 2.3.3.

[ccordoba12]

I'll take a look at that tomorrow. Thanks a lot for the feedback @petebachant, perfect timing!

[stonebig]

Well, I don't see the problem on winpython with python3.4.3 32 bit + Spyder 2.3.3 + Qt4.8.6 + windows 7 64bit.
(+all wheels carefully packed by Christoph Gohlke)

https://github.com/petebachant, you may check it works with IDLE, in case it is your graphic driver:

>>> import matplotlib.pyplot as plt
>>> plt.plot([1,2,3])
>>> plt.show()

[petebachant]

I also do not have the problem on Windows, and have tried on multiple systems with different graphics drivers. An IPython Qt console can plot inline externally without a problem. I think this is a Spyder issue.

[ccordoba12]

So this is on Linux? It's true that the issue title says it, but the description mentions Windows. That's why I asked @stonebig about it.

@petebachant, are you using Kubuntu, or KDE, as your main desktop, by any chance?

[petebachant]

This is on Linux only (for me anyway). I have had the problem on both XFCE and Cinnamon desktops.

[ccordoba12]

Could you create a new conda environment and install the new PyQt packages I'm working on? For that you need to run this command after creating the env:

conda install -c ccordoba12 pyqt

Then you need to install IPython and Spyder with

conda install pygments ipython
conda install --no-deps spyder

Try to see if this error happens in that env too

[petebachant]

I gave that a try. Could not load Spyder without some additional dependencies. Once I got to that point I didn't have the IPython Qt console, which wants to downgrade Qt to install.

[ccordoba12]

@blink1073, help me out here, please. Since you're able to reproduce this error, could you run git bisect or git blame to locate the faulty commit between 2.3.2 and 2.3.3?

[ccordoba12]

Ok, I fixed the problem with the inability to change our dpi value. This will be part of 2.3.4

[blink1073]

Sorry Carlos, I was travelling today.

[blink1073]

Found it:

commit 08596df5a484cce6852e193a7b938e5c200aec43
Author: Carlos Cordoba <ccordoba12@gmail.com>
Date:   Sun Feb 8 22:17:15 2015 -0500

    External Console: Fix plotting with Matplolib Tk and Gtk backends

    Fixes issue 2022
    Fixes issue 1946
    Fixes issue 1987

    - This also lets users to set their preferred mpl backend on Mac *again* when
    using PySide.
    - To solve this we moved to handle input hooks using code from IPython.
    - We also carefully decide what input hook to use according to the mpl backend
    and operating system.

[blink1073]

Quicklink: 08596df

[ccordoba12]

Thanks @blink1073! It was easier to narrow down the problem after that :-)