@classmethod
def create(cls, experiments, params=None):
    """
        Select the mask calculator

        """
    from dials.algorithms.profile_model.gaussian_rs.algorithm import GaussianRSMaskCalculatorFactory
    if params is None:
        from dials.command_line.integrate import phil_scope
        params = phil_scope.extract()
    selection = params.profile.algorithm
    if selection == 'gaussian_rs':
        algorithm = GaussianRSMaskCalculatorFactory.create(experiments)
    else:
        raise RuntimeError('Unknown profile model algorithm')
    return algorithm
