old_contents: from hydrogen import common
  
  def define():
      l = common('tmp/t.1.node', 3)
      return l
  
  def funV( ts, coor, region, ig, mode = None ):
      from numpy import sqrt
  
      out = {}
      C = 0.5
      r = sqrt( coor[:,0]**2 + coor[:,1]**2 + coor[:,2]**2 )
      V = - C * 1.0 / r
      out['V'] = V
      return out
  
new_contents: from hydrogen import common
  
  def define():
      l = common(dim=3)
      return l
  
  def funV( ts, coor, region, ig, mode = None ):
      from numpy import sqrt
  
      out = {}
      C = 0.5
      r = sqrt( coor[:,0]**2 + coor[:,1]**2 + coor[:,2]**2 )
      V = - C * 1.0 / r
      out['V'] = V
      return out
  
subject: use tmp/mesh.vtk in hydrogen