def METHOD_NAME(self):
    np.random.seed(seed=1)
    self.system.time_step = 0.01
    self.kT = 0.5
    self.system.non_bonded_inter[0, 0].lennard_jones.set_params(
        epsilon=1.0, sigma=1.0, cutoff=2**(1.0 / 6.0), shift="auto")
    num_part = 40
    mass = 1
    for _ in range(num_part):
        self.system.part.add(
            pos=np.random.random(3) * self.system.box_l, q=1,
            v=np.sqrt(self.kT / mass) * np.random.normal(loc=[0, 0, 0]))
        self.system.part.add(
            pos=np.random.random(3) * self.system.box_l, q=-1,
            v=np.sqrt(self.kT / mass) * np.random.normal(loc=[0, 0, 0]))
    #############################################################
    #  Warmup Integration                                       #
    #############################################################
    self.system.integrator.set_steepest_descent(
        f_max=0,
        gamma=0.001,
        max_displacement=0.01)
    # warmup
    energy = self.system.analysis.energy()["total"]
    print(f"minimization: {energy:.1f}")
    for _ in range(10):
        self.system.integrator.run(10)
        energy = self.system.analysis.energy()["total"]
        print(f"minimization: {energy:.1f}")
        if energy < 2 * num_part:
            break
    self.system.integrator.set_vv()
    self.system.thermostat.set_langevin(kT=self.kT, gamma=1.0, seed=41)