def __init__(self, avmap, respsurf=None):
"""Initialize an ActiveSubspaceResponseSurface.
Parameters
----------
avmap : ActiveVariableMap
a domains.ActiveVariable map that includes the active variable
domain, which includes the active and inactive subspaces
respsurf : ResponseSurface, optional
a utils.response_surfaces.ResponseSurface object. If a
ResponseSurface is not given, a default RadialBasisApproximation is
used.
"""
if not isinstance(avmap, ActiveVariableMap):
raise TypeError('avmap should be an ActiveVariableMap.')
if respsurf == None:
self.respsurf = RadialBasisApproximation()
else:
self.respsurf = respsurf
self.avmap = avmap
