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arXiv 0811.1829cond-mat.stat-mech
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用于计算大系统态密度和增强采样的快速自适应平坦直方图增强法

Fast Adaptive Flat-histogram Ensemble for Calculating Density of States and Enhanced Sampling in Large Systems

Xin Zhou, Yi Jiang

摘要:

提出了一种快速自适应平坦直方图集成(FAFE)算法,用于估计大系统的态密度(DOS)和增强采样。FAFE计算广义系综中任意扩展变量$U$的平均值,以形成曲线$β_{s}(U) \equiv \frac{\partial S(U)}{\partial U}$上的点,即对数DOS的导数。FAFE方法不同于Wang-Landau-like(WLL)方法,它在整个仿真过程中满足详细平衡条件,并自动生成非均匀的$(β_{i}, U_{i})$数据点,以跟踪不同$U$区域和不同系统中$β_{s}(U)$的真实变化率。结合$U-$压缩转换,FAFE将所需的仿真步骤从WLL中的$O(N^{3/2})$减少到$O(N^{1/2})$,其中$N$是系统大小。我们证明了FAFE在Lennard-Jones液体中的效率,具有几个$N$值。更重要的是,我们展示了它在发现和识别不同的宏观状态,包括亚稳态相共存区域的能力。

英文摘要:

We presented an efficient algorithm, fast adaptive flat-histogram ensemble (FAFE), to estimate the density of states (DOS) and to enhance sampling in large systems. FAFE calculates the means of an arbitrary extensive variable $U$ in generalized ensembles to form points on the curve $β_{s}(U) \equiv \frac{\partial S(U)}{\partial U}$, the derivative of the logarithmic DOS. Unlike the popular Wang-Landau-like (WLL) methods, FAFE satisfies the detailed-balance condition through out the simulation and automatically generates non-uniform $(β_{i}, U_{i})$ data points to follow the real change rate of $β_{s}(U)$ in different $U$ regions and in different systems. Combined with a $U-$compression transformation, FAFE reduces the required simulation steps from $O(N^{3/2})$ in WLL to $O(N^{1/2})$, where $N$ is the system size. We demonstrate the efficiency of FAFE in Lennard-Jones liquids with several $N$ values. More importantly, we show its abilities in finding and identifying different macroscopic states including meta-stable states in phase co-existing regions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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