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

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).