pairwise_interactions.py 文件源码

def d2fdx2(self, x):
        sech_aR = 1.0 / np.cosh(self.a * (x - self.R0))
        tanh_aR = np.tanh(self.a * (x-self.R0))
        return -2.0 * self.V0 * self.a * self.a * sech_aR * sech_aR * tanh_aR