Issue 1:
I'm running on a CentOS ( release 7.4.1708 ) Linux environment that is on a Linux-based HPC. Python version 2.7.

I'm running a script to visualize TF-IDF values using the Isomap algorithm ( incorporating sci-kit learns) and then using a 3D scatterplot to visualize possible relationships between tfidf values of a corpus. This has already been preprocessed. This is my code:

def Isomap(tfidf):
jon = pd.read_csv(tfidf)
le = preprocessing.LabelEncoder()
tims = jon.apply(le.fit_transform)
iso = manifold.Isomap(n_neighbors=2, n_components=3)
john = iso.fit_transform(tims)
fig = plt.figure(1)
colors = ['red', 'yellow', 'green']
ax = fig.add_subplot(111, projection='3d')
ax.scatter(john[:,0], john[:,1],john[:,2],color=colors,alpha=.5) # x,y,z coord. jon 1-3
plt.title('Isomap of candiates')
plt.xlabel('x')
plt.ylabel('y')
plt.show()
plt.savefig('isomap.png')

However, the error code reads as so:

Traceback (most recent call last):
File "MasterScript.py", line 157, in <module>
Isomap('tfidf.txt')
File "MasterScript.py", line 134, in Isomap
fig = plt.figure(1)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/pyplot.py", line 535, in figure
**kwargs)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 44, in new_figure_manager
return new_figure_manager_given_figure(num, thisFig)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 51, in new_figure_manager_given_figure
canvas = FigureCanvasQTAgg(figure)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 242, in __init__
super(FigureCanvasQTAgg, self).__init__(figure=figure)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 66, in __init__
super(FigureCanvasQTAggBase, self).__init__(figure=figure)
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 236, in __init__
_create_qApp()
File "/util/common/python/anaconda-5.0.0/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 144, in _create_qApp
raise RuntimeError('Invalid DISPLAY variable')
RuntimeError: Invalid DISPLAY variable

I'm not exactly sure if it is a fault of matplotlib or my own handling of the library. Any help would be appreciated.

Issue 2:
In my AWS Ubuntu 14.02 instance I installed the matplotlib dependencies and then via pip I installed matplotlib:

sudo apt-get build-dep python-matplotlib

sudo pip install matplotlib

sudo pip freeze:

matplotlib==1.4.0

in a brand new file plotting1.py I wrote:

!/usr/bin/python

from pylab import *

plot([1,2,3])

show()

after typying chmod +x plotting1.py, I executed the little script:

time python plotting1.py

Traceback (most recent call last):

File "plotting1.py", line 4, in

plot([1,2,3])

File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py", line 3086, in plot

ax = gca()

File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py", line 827, in gca

ax = gcf().gca(*_kwargs)

File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py", line 461, in gcf

return figure()

File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py", line 434, in figure

*_kwargs)

File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt4ag g.py", line 47, in new_figure_manager

return new_figure_manager_given_figure(num, thisFig)

File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt4ag g.py", line 54, in new_figure_manager_given_figure

canvas = FigureCanvasQTAgg(figure)

File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt4ag g.py", line 72, in init

FigureCanvasQT.init(self, figure)

File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt4.p y", line 68, in init

_create_qApp()

File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt5.p y", line 139, in _create_qApp

raise RuntimeError('Invalid DISPLAY variable')

RuntimeError: Invalid DISPLAY variable

real 0m0.404s

user 0m0.284s

What do I have to do now?

Looking forward to your kind help.

Kind regards.

Marco