def check_covariance_Kgrad_x(covar, relchange=1E-5, threshold=1E-2, check_diag=True):
        """
        check_covariance_Kgrad_x(ACovarianceFunction covar, limix::mfloat_t relchange=1E-5, limix::mfloat_t threshold=1E-2, bool check_diag=True) -> bool

        Parameters
        ----------
        covar: limix::ACovarianceFunction &
        relchange: limix::mfloat_t
        threshold: limix::mfloat_t
        check_diag: bool

        check_covariance_Kgrad_x(ACovarianceFunction covar, limix::mfloat_t relchange=1E-5, limix::mfloat_t threshold=1E-2) -> bool

        Parameters
        ----------
        covar: limix::ACovarianceFunction &
        relchange: limix::mfloat_t
        threshold: limix::mfloat_t

        check_covariance_Kgrad_x(ACovarianceFunction covar, limix::mfloat_t relchange=1E-5) -> bool

        Parameters
        ----------
        covar: limix::ACovarianceFunction &
        relchange: limix::mfloat_t

        check_covariance_Kgrad_x(ACovarianceFunction covar) -> bool

        Parameters
        ----------
        covar: limix::ACovarianceFunction &

        """
        return _core.ACovarianceFunction_check_covariance_Kgrad_x(covar, relchange, threshold, check_diag)