I am running a simple python script in the server:
import matplotlib.pyplot as plt
import numpy as np
x = np.random.randn(60)
y = np.random.randn(60)
plt.scatter(x, y, s=20)
out_png = 'path/to/store/out_file.png'
plt.savefig(out_png, dpi=150)
I try to use the command python example.py
in this server which has matplotlib 1.5.1 installed it fails with the error:
Traceback (most recent call last):
File "example.py", line 7, in <module>
plt.scatter(x, y, s=20)
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 3241, in scatter
ax = gca()
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 928, in gca
return gcf().gca(**kwargs)
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 578, in gcf
return figure()
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 527, in figure
**kwargs)
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.py", line 84, in new_figure_manager
return new_figure_manager_given_figure(num, figure)
File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.py", line 92, in new_figure_manager_given_figure
window = Tk.Tk()
File "/usr/local/lib/python2.7/lib-tk/Tkinter.py", line 1810, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
What is happening here?
Matplotlib chooses Xwindows backend by default. You need to set matplotlib to not use the Xwindows backend.
Add this code to the start of your script (before importing pyplot) and try again:
import matplotlib
matplotlib.use('Agg')
Or add to .config/matplotlib/matplotlibrc
line backend: Agg
to use non-interactive backend.
echo "backend: Agg" > ~/.config/matplotlib/matplotlibrc
Or when connect to server use ssh -X remoteMachine
command to use Xwindows.
Also you may try to export display: export DISPLAY=mymachine.com:0.0
.
For more info: https://matplotlib.org/faq/howto_faq.html#matplotlib-in-a-web-application-server