shown in Ref. [@alam], by carrying out a maximum likelihood analysis which combines the statefinder diagnostic with realistic expectations from the SNAP experiment, the averaged-over-redshift statefinder pair $\{\bar{s}, \bar{r}\}$ is convincingly demonstrated to be useful diagnostic tool in successfully differentiating between the cosmological constant and dynamical models of dark energy. In this section we apply the statefinder diagnostic to the NGCG model.

In what follows we will calculate the rangefinder parameters for the NGCG model and plot the evolution trajectories of the model in the statefinder parameter-plane. The statefinder parameters can be expressed in terms of the total energy density $\rho$ and the total pressure $p$ in the Universe: $$r=1+{9(\rho+p)\over
2\rho}{\dot{p}\over\dot{\rho}}~,~~~~s={(\rho+p)\over
p}{\dot{p}\over\dot{\rho}}~.$$ The total energy of the Universe is conserved, so we have $\dot{\rho}=-3H(\rho+p).$ Since the dust matter does not have pressure, the total pressure of the cosmic fluids is provided only by dark energy component, $p=p_X=w_X\rho_X$. Then making use of $\dot{\rho}=-3H(\rho+p)$ and $\dot{\rho}_X=-3H(1+w_X^{(e)})\rho_X$, we can get the concrete expression of the statefinder parameters $$r=1+{9\over 2}w_X\Omega_X(1+w_X^{(e)})~,~~~~s=1+w_X^{(e)}~.$$ Here $w_X^{(e)}$ and $\Omega_X$ are given by (\[wXeff\]) and (\[OmegaX\]), respectively. Though the relationship between statefinder parameters $r$ and $s$, namely the function $r(s)$, might be derived analytically in principle, we do not give 