matplotlib raises error

[rtotheb2000]

Hi,

I am trying to install matplotlib on a fresh conda installation, which throws:

Linking packages ...
[COMPLETE]|###################################################################| 100%
dbus post-link :: /etc/machine-id not found ..
dbus post-link :: .. using /proc/sys/kernel/random/boot_id

.

Information about the os:

lsb_release -a

LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID: Scientific
Description: Scientific Linux release 6.8 (Carbon)
Release: 6.8
Codename: Carbon

Using matplotlib.pyplot in a script then leads to

QXcbConnection: Could not connect to display

and trying to set

import matplotlib as mpl
mpl.use('Agg')
import matplotlib.pyplot as plt

raised

python3.5/site-packages/matplotlib/__init__.py:1357: UserWarning: This call to matplotlib.use() has no effect because the backend has already been chosen;

Can someone help with this error? I am sorry, if that is not actually a bug and I am just to uninformed to understand the issue. But setting up a new env and only trying to install matplotlib created the exact same behavior.

[ccordoba12]

@mingwandroid?

[mingwandroid]

The text is informative only, nothing to worry about.

How are you using matplotlib? From with Spyder? If so, this may be useful:

http://stackoverflow.com/questions/23452550/spyder-matplotlib-userwarning-this-call-to-matplotlib-use-has-no-effect-becau

[rtotheb2000]

@mingwandroid I do not use it from any IDE (spyder or any other), I just run a script python test.py importing pyplot as specified above and it raises the described error.

Minimal example that raises the error:

import matplotlib.pyplot as plt
plt.plot()

python test.py
QXcbConnection: Could not connect to display localhost:0.0
Aborted (core dumped)

[rtotheb2000]

This seems to work:

import matplotlib as mpl
mpl.use('Agg')
import matplotlib.pyplot as plt
plt.ioff() #http://matplotlib.org/faq/usage_faq.html (interactive mode)

source: Stackoverflow - Problem running python/matplotlib in background after ending ssh session

And this warning

python3.5/site-packages/matplotlib/__init__.py:1357: UserWarning: This call to matplotlib.use() has no effect because the backend has already been chosen;

goes away when I import matplotlib first (before numpy, pandas, seaborn, etc.). So my guess is that maybe seaborn or pandas sets some kind of matplotlib env already.

[mingwandroid]

Ah yes, of course. Thanks for updating us.