def getInterface(self,phi=None,smoothing_width=None):
"""
creates a characteristic function which is 1 over the over the length
*2*h*smoothing_width* around the interface and zero elsewhere
"""
if smoothing_width is None: smoothing_width = self.__smooth
if phi is None: phi = self.__phi
s=smoothing_width*self.__h
phi_on_h=es.interpolate(phi,esc.Function(self.__domain))
return es.whereNegative(abs(phi_on_h)-s)
def getSmoothedJump(self,phi=None,smoothing_width=None):
"""
Creates a smooth interface from -1 to 1 over the length
*2*h*smoothing_width* where -1 is used where the level set is negative
and 1 where the level set is 1.
"""
if smoothing_width is None: smoothing_width = self.__smooth
if phi is None: phi = self.__phi
s=smoothing_width*self.__h
phi_on_h=es.interpolate(phi,esc.Function(self.__domain))
mask_neg = es.whereNonNegative(-s-phi_on_h)
mask_pos = es.whereNonNegative(phi_on_h-s)
mask_interface = 1.-mask_neg-mask_pos
interface=phi_on_h/s
return - mask_neg + mask_pos + mask_interface * interface
