用于超电大散射计算MLFMA并行化及其关键问题的研究

发布时间：2018-02-12 13:19

本文关键词： 矩量法多层快速多极子方法 MPI OpenMP 高阶基函数金属介质混合目标　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：科技的迅速发展使得电磁波高频应用越来越广泛,在计算电磁学领域中电大、超电大目标的电磁散射特性分析伴随着工程需求越来越重要;多层快速多极子方法作为电磁问题分析的快速算法,以其求解复杂度低、计算精度高等优点成为分析电大尺寸散射辐射问题的重要手段和研究热点。本文重点研究了多层快速多极子基于OpenMP的细粒度多线程并行以及基于MPI的粗粒度多进程并行;同时考虑到高阶基函数在保持计算精度和收敛性的前提下仅仅需要更少的未知量和内存需求,进一步将高阶基函数引入到并行化的多层快速多极子程序中,提高在相同计算平台上求解电大、超电大目标电磁散射特性的能力。金属介质混合结构的电磁散射特性分析对军用目标的隐身特性分析至关重要,因此本文还将基于体面积分方程的数值分析方法加到到多层快速多极子的并行化中,为更快更好的研究目标的电磁散射特性分析做了有效地铺垫。首先,本文简要介绍一下应用多层快速多极子算法的理论基础—矩量法,阐述并行计算过程需要的软硬件环境;具体讲述开发过程中所使用的基于MPI和OpenMP的编程模型以及衡量并行效率的评估标准。其次,本文详细分析了求解积分方程过程中加速矩矢相乘的多层快速多极子方法。针对并行算法的程序开发,从基函数的判定到多层模型的建立,再到附近组阻抗、转移因子等预处理的完成,以及最终的矩矢相乘迭代过程的实现,一一进行了有效的分析,为获得高效的计算速度以及充分的并行度,做了大量有效的工作。如基函数判定实现了MPI和OpenMP两级并行,转移因子针对位于过渡层上下的区别分别对待,为实现高效的迭代求解进行的准备工作等等。再次,基于曲面三角形贴片模拟散射体表面,将新型行驻波基函数与并行多层快速多极子算法进行有效结合,实现超电大目标散射特性的有效分析。最后,由于在实际的工程应用中,金属介质混合的电大目标的电磁特性一直是众多学者们探索的热点,本文将基于体面积分方程的矩量法与并行的多层快速多极子方法结合起来,对复杂媒质金属混合目标的电磁散射问题进行高效求解。
[Abstract]:With the rapid development of science and technology, the application of high frequency electromagnetic wave is more and more extensive. In the field of electromagnetism, the electromagnetic scattering characteristic analysis of superelectrically large target is becoming more and more important. As a fast algorithm for electromagnetic problem analysis, multilayer fast multipole method has low complexity. High computational accuracy has become an important means and research hotspot in analyzing electrically large size scattering radiation. In this paper, the fine granularity multithread parallelism based on OpenMP and the coarse-grained multiprocess parallelism based on MPI are studied in detail. Considering that higher order basis functions only need less unknowns and memory requirements while preserving the accuracy and convergence of computation, higher order basis functions are further introduced into parallel multilayer fast multipole subprograms. Improving the ability to solve the electromagnetic scattering characteristics of electrically large and superelectrically large targets on the same computing platform. The analysis of electromagnetic scattering characteristics of metal dielectric mixed structures is very important to the analysis of stealth characteristics of military targets. Therefore, the numerical analysis method based on the decent integral equation is applied to the parallelization of multilayer fast multipole, which provides an effective basis for the analysis of the electromagnetic scattering characteristics of the target in a faster and better way. This paper briefly introduces the theoretical basis of the multilayer fast multipole algorithm, the method of moments, and describes the software and hardware environment required for the parallel computing process. The programming model based on MPI and OpenMP used in the development process and the evaluation standard to measure the efficiency of parallelism are described in detail. Secondly, In this paper, the multilayer fast multipole method of accelerating the moment vector multiplication in solving the integral equation is analyzed in detail. For the program development of parallel algorithm, from the decision of the basis function to the establishment of the multilayer model, and then to the nearby group impedance, The completion of preprocessing such as transfer factor, and the realization of the final iterative process of moment vector multiplication, are all analyzed effectively, in order to obtain efficient computation speed and sufficient parallelism. A lot of effective work has been done. For example, the basis function decision realizes the parallel of MPI and OpenMP, the transfer factor is treated separately according to the difference between the transition layers, the preparation for efficient iterative solution, and so on. Based on curved triangular patch to simulate the surface of scatterer, the new traveling standing wave basis function and parallel multilayer fast multipole algorithm are effectively combined to realize the effective analysis of the scattering characteristics of superelectrically large objects. Finally, because of the practical engineering application, The electromagnetic characteristics of electrically large targets with mixed metal media have been a hot topic for many scholars. In this paper, the method of moments based on the decent integral equation is combined with the parallel multilayer fast multipole method. The electromagnetic scattering problem of metal mixed target in complex medium is solved efficiently.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM15

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