def xydist(p1=(0.0, 0.0), p2=(0.0, 0.0)):
 return numpy.sqrt((pow((p1[0] - p2[0]), 2) + pow((p1[1] - p2[1]), 2)))

def xydist ( p1 = ( 0.0 , 0.0 ) , p2 = ( 0.0 , 0.0 ) ) : return numpy . sqrt ( ( pow ( ( p1 [ 0 ] - p2 [ 0 ] ) , 2 ) + pow ( ( p1 [ 1 ] - p2 [ 1 ] ) , 2 ) ) )
helper function returning the cartesian distance between p1 and p2 .