def _parameter_constraints(self, theta_E, gamma, q, phi_G, s_scale):
        """
        sets bounds to parameters due to numerical stability
        :param theta_E:
        :param gamma:
        :param q:
        :param phi_G:
        :param s_scale:
        :return:
        """
        if theta_E < 0:
            theta_E = 0
        if s_scale < 0.00000001:
            s_scale = 0.00000001
        if gamma < 1.2:
            gamma = 1.2
            theta_E = 0
        if gamma > 2.9:
            gamma = 2.9
            theta_E = 0
        if q < 0.01:
            q = 0.01
            theta_E = 0
        if q > 1:
            q = 1.
            theta_E = 0
        return theta_E, gamma, q, phi_G, s_scale
sets bounds to parameters due to numerical stability
        :param theta_E:
        :param gamma:
        :param q:
        :param phi_G:
        :param s_scale:
        :return: