Fast adaptive flat-histogram ensemble to enhance the sampling in large systems

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2015-09, Vol.58 (9), p.5-10, Article 590501
• Main Authors: Xu, Shun, Zhou, Xin, Jiang, Yi, Wang, YanTing
• Format: Article
• Language: English
• Subjects: Adaptive sampling; Adaptive systems; Algorithms; Astronomy; Classical and Continuum Physics; Computation; Density of states; Estimates; Mathematical analysis; Metastable state; Observations and Techniques; Physics; Physics and Astronomy; Potential energy; Sampling; Temperature dependence; Transformations; 增强方法; 大系统; 平面; 快速自适应; 曲线计算; 物理变量; 直方图; 计算复杂度
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-015-5690-7

An efficient novel algorithm was developed to estimate the Density of States（DOS） for large systems by calculating the ensemble means of an extensive physical variable, such as the potential energy, U, in generalized canonical ensembles to interpolate the interior reverse temperature curve β_s（U）=SU/U, where S（U） is the logarithm of the DOS. This curve is computed with different accuracies in different energy regions to capture the dependence of the reverse temperature on U without setting prior grid in the U space. By combining with a U-compression transformation, we decrease the computational complexity from O（N3/2） in the normal Wang Landau type method to O（N1/2） in the current algorithm, as the degrees of freedom of system N. The efficiency of the algorithm is demonstrated by applying to Lennard Jones fluids with various N, along with its ability to find different macroscopic states, including metastable states.