content: import matplotlib as mpl
  mpl.use('Agg')
  import numpy
  from pyearth import Earth
  from matplotlib import pyplot
  
  #=========================================================================
  # V-Function Example
  #=========================================================================
  # Create some fake data
  numpy.random.seed(0)
  m = 1000
  n = 10
  X = 80 * numpy.random.uniform(size=(m, n)) - 40
  y = numpy.abs(X[:, 6] - 4.0) + 1 * numpy.random.normal(size=m)
  
  # Fit an Earth model
  model = Earth()
  model.fit(X, y)
  
  # Print the model
  print model.trace()
  print model.summary()
  
  # Plot the model
  y_hat = model.predict(X)
  pyplot.figure()
  pyplot.plot(X[:, 6], y, 'r.')
  pyplot.plot(X[:, 6], y_hat, 'b.')
  pyplot.xlabel('x_6')
  pyplot.ylabel('y')
  pyplot.title('Simple Earth Example')
  pyplot.savefig('simple_earth_example.png')
  
  #=========================================================================
  # Hinge plot
  #=========================================================================
  from xkcdify import XKCDify
  x = numpy.arange(-10, 10, .1)
  y = x * (x > 0)
  
  fig = pyplot.figure(figsize=(10, 5))
  pyplot.plot(x, y)
  ax = pyplot.gca()
  
  pyplot.title('Basic Hinge Function')
  pyplot.xlabel('x')
  pyplot.ylabel('h(x)')
  pyplot.annotate('x=t', (0, 0), xytext=(-30, 30), textcoords='offset points',
                  arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
  XKCDify(ax)
  pyplot.setp(ax, frame_on=False)
  pyplot.savefig('hinge.png')
  
  #=========================================================================
  # Piecewise Linear Plot
  #=========================================================================
  m = 1000
  x = numpy.arange(-10, 10, .1)
  y = 1 - 2 * (1 - x) * (x < 1) + 0.5 * (x - 1) * (x > 1)
  
  pyplot.figure(figsize=(10, 5))
  pyplot.plot(x, y)
  ax = pyplot.gca()
  pyplot.xlabel('x')
  pyplot.ylabel('y')
  pyplot.title('Piecewise Linear Function')
  XKCDify(ax)
  pyplot.setp(ax, frame_on=False)
  pyplot.savefig('piecewise_linear.png')
  