'Transform constrained parameters used in likelihood evaluation
to unconstrained parameters used by the optimizer
Parameters
constrained : array_like
Array of constrained parameters used in likelihood evalution, to be
transformed.
Returns
unconstrained : array_like
Array of unconstrained parameters used by the optimizer.
Notes
This is a noop in the base class, subclasses should override where
appropriate.'

def untransform_params(self, constrained):

    return np.array(constrained, ndmin=1)
