'Initializes the object and starts the computation of the Voronoi
diagram.
points : The generator points of the Voronoi diagram assumed to be
all on the sphere with radius supplied by the radius parameter and
center supplied by the center parameter.
radius : The radius of the sphere. Will default to 1 if not supplied.
center : The center of the sphere. Will default to the origin if not
supplied.'

def __init__(self, points, radius=None, center=None):

    self.points = points
    if np.any(center):
        self.center = center
    else:
        self.center = np.zeros(3)
    if radius:
        self.radius = radius
    else:
        self.radius = 1
    self.vertices = None
    self.regions = None
    self._tri = None
    self._calc_vertices_regions()
