matplotlib pgf: OSError: No such file or directory in subprocess.py - matplotlib

Question

I try to use matplotlib to create a pgf file for LaTeX:
from matplotlib.pyplot import subplots
from numpy import linspace
x = linspace(0, 100, 30)
fig, ax = subplots(figsize = (10, 6))
ax.scatter(x, x)
fig.tight_layout()
fig.savefig('/home/mark/dicp/python/figure.pgf')
But I get OSError: [Errno 2] No such file or directory:
Traceback (most recent call last):
File "visualize/latex_figs.py", line 32, in <module>
fig.savefig('/home/mark/dicp/python/figure.pgf')
File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py", line 1421, in savefig
self.canvas.print_figure(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py", line 2220, in print_figure
**kwargs)
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py", line 1957, in print_pgf
return pgf.print_pgf(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pgf.py", line 818, in print_pgf
self._print_pgf_to_fh(fh, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pgf.py", line 797, in _print_pgf_to_fh
RendererPgf(self.figure, fh),
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pgf.py", line 409, in __init__
self.latexManager = LatexManagerFactory.get_latex_manager()
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pgf.py", line 223, in get_latex_manager
new_inst = LatexManager()
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pgf.py", line 305, in __init__
cwd=self.tmpdir)
File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
It also generates this part of the output file:
%% [whole bunch of comments]
\begingroup%
\makeatletter%
\begin{pgfpicture}%
\pgfpathrectangle{\pgfpointorigin}{\pgfqpoint{10.000000in}{6.000000in}}%
\pgfusepath{use as bounding box}%
I do not understand what OSError: No such file or directory in subprocesses.py has to do with anything... The file I'm trying to save is writable. Am I misunderstanding something, or is this a bug I should report?

Answer 1

I also had this problem while trying to run the example scripts. The problem occurs where backend_pgf.py first tries to use the default LaTeX command. It seems that the PGF backend assumes that it should use xelatex by default. If the problem is the same for you as for me, then you have two options:
add the key "pgf.texsystem" : "pdflatex" (or lualatex, whatever) to your matplotlib.rcParams. For example, add the following snippet to the top of your script:
import matplotlib
pgf_with_rc_fonts = {"pgf.texsystem": "pdflatex"}
matplotlib.rcParams.update(pgf_with_rc_fonts)
ensure that you have xelatex, and that it is on your PATH, and use that as the default latex command (i.e. assuming you're on a Mac or Linux system, which xelatex should return a path).