matplotlib pgf savefig(pdf) fails
Question: On a modern texlive installation on fedora 20, using pgf backend fails in
savefig ('blah.pdf').

Example:

    
    
    # -*- coding: utf-8 -*-
    
    import matplotlib as mpl
    mpl.use("pgf")
    pgf_with_rc_fonts = {
        "font.family": "serif",
        "font.serif": [],                   # use latex default serif font
        "font.sans-serif": ["DejaVu Sans"], # use a specific sans-serif font
    }
    mpl.rcParams.update(pgf_with_rc_fonts)
    
    import matplotlib.pyplot as plt
    plt.figure(figsize=(4.5,2.5))
    plt.plot(range(5))
    plt.text(0.5, 3., "serif")
    plt.text(0.5, 2., "monospace", family="monospace")
    plt.text(2.5, 2., "sans-serif", family="sans-serif")
    plt.text(2.5, 1., "comic sans", family="Comic Sans MS")
    plt.xlabel(u"µ is not $\\mu$")
    plt.tight_layout(.5)
    

trace back:

    
    
    Traceback (most recent call last):
      File "testpgf.py", line 20, in <module>
        plt.tight_layout(.5)
      File "/usr/lib64/python2.7/site-packages/matplotlib/pyplot.py", line 1255, in tight_layout
        fig.tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad, rect=rect)
      File "/usr/lib64/python2.7/site-packages/matplotlib/figure.py", line 1600, in tight_layout
        renderer = get_renderer(self)
      File "/usr/lib64/python2.7/site-packages/matplotlib/tight_layout.py", line 222, in get_renderer
        renderer = canvas.get_renderer()
      File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 925, in get_renderer
        return RendererPgf(self.figure, None, dummy=True)
      File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 409, in __init__
        self.latexManager = LatexManagerFactory.get_latex_manager()
      File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 223, in get_latex_manager
        new_inst = LatexManager()
      File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_pgf.py", line 305, in __init__
        cwd=self.tmpdir)
      File "/usr/lib64/python2.7/subprocess.py", line 711, in __init__
        errread, errwrite)
      File "/usr/lib64/python2.7/subprocess.py", line 1308, in _execute_child
        raise child_exception
    OSError: [Errno 2] No such file or directory
    


Answer: OK, problem is that according to <http://matplotlib.org/1.3.1/users/pgf.html>
the default tex processor is xelatex, which was not installed. Either 1) sudo
yum install texlive-xetex-bin or 2) set pgf to use some other latex processor:

    
    
    pgf_with_pdflatex = {
        "pgf.texsystem": "lualatex",
        "pgf.preamble": [
            r'\usepackage{amsmath}',
            r'\usepackage[scientific-notation=true]{siunitx}',
        ##      r"\usepackage[utf8x]{inputenc}",
        ##      r"\usepackage[T1]{fontenc}",
            ]
    }
    mpl.rcParams.update(pgf_with_pdflatex)
    

