text: """
  FLOW: Vadose: van Genuchten
  ===========================
  
  Shows the water retention curve and the hydraulic conductivity
  function for a number of soil types.
  
  For more information about the parameters used see:
  
  The RETC code for quantifying the hydraulic functions of unsaturated
  soils, Van Genuchten, M Th, Leij, F J, Yates, S R
  """
  import matplotlib.pyplot as plt
  
  from SimPEG import Mesh
  from SimPEG.FLOW import Richards
  
  
  def run(plotIt=True):
      mesh = Mesh.TensorMesh([10])
      VGparams = Richards.Empirical.VanGenuchtenParams()
      leg = []
      for p in dir(VGparams):
          if p[0] == '_':
              continue
          leg += [p]
          params = getattr(VGparams, p)
          k_fun, theta_fun = Richards.Empirical.van_genuchten(mesh, **params)
          theta_fun.plot(ax=plt.subplot(121))
          k_fun.plot(ax=plt.subplot(122))
  
      plt.legend(leg, loc=3)
  
  if __name__ == '__main__':
      run()
      plt.show()
  