text: #!/usr/bin/env python
  """
  You can use TeX to render all of your matplotlib text if the rc
  parameter text.usetex is set.  This works currently on the agg and ps
  backends, and requires that you have tex and the other dependencies
  described at http://matplotlib.sf.net/matplotlib.texmanager.html
  properly installed on your system.  The first time you run a script
  you will see a lot of output from tex and associated tools.  The next
  time, the run may be silent, as a lot of the information is cached in
  ~/.tex.cache
  
  """
  from matplotlib import rc
  from numpy import arange, cos, pi
  from matplotlib.pyplot import figure, axes, plot, xlabel, ylabel, title, \
       grid, savefig, show
  
  
  rc('text', usetex=True)
  rc('font', family='serif')
  figure(1, figsize=(6,4))
  ax = axes([0.1, 0.1, 0.8, 0.7])
  t = arange(0.0, 1.0+0.01, 0.01)
  s = cos(2*2*pi*t)+2
  plot(t, s)
  
  xlabel(r'\textbf{time (s)}')
  ylabel(r'\textit{voltage (mV)}',fontsize=16)
  title(r"\TeX\ is Number $\displaystyle\sum_{n=1}^\infty\frac{-e^{i\pi}}{2^n}$!",
        fontsize=16, color='r')
  grid(True)
  savefig('tex_demo')
  
  
  show()
  