get the parameter groups with atleast one adjustable parameter

        Returns
        -------
        adj_par_groups : list
            a list of parameter groups with  at least one adjustable parameter

def adj_par_groups(self):
        """get the parameter groups with atleast one adjustable parameter

        Returns
        -------
        adj_par_groups : list
            a list of parameter groups with  at least one adjustable parameter

        """
        adj_pargp = []
        for pargp in self.par_groups:
            ptrans = self.parameter_data.loc[self.parameter_data.pargp==pargp,"partrans"].values
            if "log" in ptrans or "none" in ptrans:
                adj_pargp.append(pargp)
        return adj_pargp