text: # -*- coding: utf-8 -*-
  """
  Created on Tue May 27 21:21:19 2014
  
  @author: rlabbe
  """
  import matplotlib.pyplot as plt
  
  
  def show_fixed_lag_numberline():
      fig = plt.figure()
      ax = fig.add_subplot(111)
      ax.set_xlim(0,10)
      ax.set_ylim(0,10)
  
      # draw lines
      xmin = 1
      xmax = 9
      y = 5
      height = 1
  
      plt.hlines(y, xmin, xmax)
      plt.vlines(xmin, y - height / 2., y + height / 2.)
      plt.vlines(4.5, y - height / 2., y + height / 2.)
      plt.vlines(6, y - height / 2., y + height / 2.)
      plt.vlines(xmax, y - height / 2., y + height / 2.)
      plt.vlines(xmax-1, y - height / 2., y + height / 2.)
  
      # add numbers
      plt.text(xmin, y-1.1, '$x_0$', fontsize=20, horizontalalignment='center')
      plt.text(xmax, y-1.1, '$x_k$', fontsize=20, horizontalalignment='center')
      plt.text(xmax-1, y-1.1, '$x_{k-1}$', fontsize=20, horizontalalignment='center')
      plt.text(4.5, y-1.1, '$x_{k-N+1}$', fontsize=20, horizontalalignment='center')
      plt.text(6, y-1.1, '$x_{k-N+2}$', fontsize=20, horizontalalignment='center')
      plt.text(2.7, y-1.1, '.....', fontsize=20, horizontalalignment='center')
      plt.text(7.2, y-1.1, '.....', fontsize=20, horizontalalignment='center')
  
      plt.axis('off')
      plt.show()
  
  if __name__ == '__main__':
  
      #show_2d_transform()
      #show_sigma_selections()
  
      show_sigma_transform(True)
      #show_four_gps()
      #show_sigma_transform()
      #show_sigma_selections()
  
  