Returns (i, val) where i is the component index (0 - 2)
    which has largest absolute value and val is the value
    of the component.

def LargestComponent(self):
    """
    Returns (i, val) where i is the component index (0 - 2)
    which has largest absolute value and val is the value
    of the component.
    """
    if abs(self.x) > abs(self.y):
      if abs(self.x) > abs(self.z):
        return (0, self.x)
      else:
        return (2, self.z)
    else:
      if abs(self.y) > abs(self.z):
        return (1, self.y)
      else:
        return (2, self.z)