Linse Björn, Linse Per
Physical Chemistry, Department of Chemistry, Lund University, P.O. Box 124, S-22100 Lund, Sweden.
J Chem Phys. 2014 Nov 14;141(18):184114. doi: 10.1063/1.4901119.
Numerical properties of the smooth particle mesh Ewald (SPME) sum [U. Essmann, L. Perera, M. L. Berkowitz, T. Darden, H. Lee, and L. G. Pedersen, J. Chem. Phys. 103, 8577 (1995)] have been investigated by molecular dynamics simulation of ionic solutions and dipolar fluids. Scaling dependence of execution time on the number of particles at optimal performance have been determined and compared with the corresponding data of the standard Ewald (SE) sum. For both types of systems and over the range from N = 10(3) to 10(5) particles, the SPME sum displays a sub O(N ln N) complexity, whereas the SE sum possesses an O(N(3/2)) complexity. The breakeven of the simulation times appears at O(10(3)) particles, and the SPME sum is ≈20 times faster than the SE sum at 10(5) particles. Furthermore, energy truncation error and the energy and force execution time of the reciprocal space evaluation as function of the number of particles and the convergence parameters of the SPME sum have been determined for both types of systems containing up to 10(6) particles.
通过对离子溶液和偶极流体的分子动力学模拟，研究了光滑粒子网格埃瓦尔德（SPME）求和[U. 埃斯曼、L. 佩雷拉、M. L. 伯克维茨、T. D. 达登、H. 李和L. G. 佩德森，《化学物理杂志》103, 8577 (1995)]的数值特性。确定了在最佳性能下执行时间对粒子数的标度依赖性，并与标准埃瓦尔德（SE）求和的相应数据进行了比较。对于这两种类型的系统，在粒子数从N = 10³到10⁵的范围内，SPME求和显示出低于O(N ln N)的复杂度，而SE求和具有O(N³/²)的复杂度。模拟时间的收支平衡点出现在O(10³)个粒子处，在10⁵个粒子时，SPME求和比SE求和快约20倍。此外，对于包含多达10⁶个粒子的两种类型的系统，已经确定了能量截断误差以及作为粒子数和SPME求和收敛参数函数的互易空间评估的能量和力执行时间。
