Matplotlib pgf 后端针对所有图返回“LaTeX 返回错误，可能是缺少字体或序言中有错误”

Question

我花了几个小时尝试让 PGF 后端工作。我尝试使用 xelatex，但它根本无法运行。

现在我做了这个例子：

# -*- coding: utf-8 -*-

import matplotlib as mpl
mpl.use("pgf")
pgf_with_rc_fonts = {
    "pgf.texsystem": "pdflatex"
}
mpl.rcParams.update(pgf_with_rc_fonts)

import matplotlib.pyplot as plt
plt.figure(figsize=(4.5,2.5))
plt.plot(range(5))
plt.savefig('figure.pgf')

这会引发错误。我马上就会讲到。但是，如果我删除 plt.savefig('figure.pgf')，错误就会消失。终端返回的输出是：

Traceback (most recent call last):
  File "Dokumenter/fys2130/oblig4/test.py", line 13, in <module>
    plt.savefig('figure.pgf')
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py", line 577, in savefig
    res = fig.savefig(*args, **kwargs)
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/figure.py", line 1470, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backend_bases.py", line 2194, in print_figure
    **kwargs)
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 835, in print_pgf
    self._print_pgf_to_fh(fh, *args, **kwargs)
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 814, in _print_pgf_to_fh
    RendererPgf(self.figure, fh),
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 422, in __init__
    self.latexManager = LatexManagerFactory.get_latex_manager()
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 232, in get_latex_manager
    new_inst = LatexManager()
  File "/home/marius/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 322, in __init__
    raise LatexError("LaTeX returned an error, probably missing font or error in preamble:\n%s" % stdout)
matplotlib.backends.backend_pgf.LatexError: LaTeX returned an error, probably missing font or error in preamble:
This is pdfTeX, Version 3.1415926-2.4-1.40.13 (TeX Live 2012/Debian)
 restricted \write18 enabled.
**---! /home/marius/.texmf-var/web2c/pdftex/pdflatex.fmt doesn't match pdftex.pool
(Fatal format file error; I'm stymied)

我的matplotlib版本是1.4.2。

我的问题是，我该如何解决这样的问题？

我不知道从哪儿开始。