The method of establishing data structures plays an important role in the efficiency of parallel multilevel fast multipole algorithm（PMLFMA）.Considering the main complements of multilevel fast multipole algorithm（M...The method of establishing data structures plays an important role in the efficiency of parallel multilevel fast multipole algorithm（PMLFMA）.Considering the main complements of multilevel fast multipole algorithm（MLFMA） memory,a new parallelization strategy and a modified data octree construction scheme are proposed to further reduce communication in order to improve parallel efficiency.For far interaction,a new scheme called dynamic memory allocation is developed.To analyze the workload balancing performance of a parallel implementation,the original concept of workload balancing factor is introduced and verified by numerical examples.Numerical results show that the above measures improve the parallel efficiency and are suitable for the analysis of electrical large-scale scattering objects.展开更多
A full-wave analysis of the electromagnetic problem of a three-dimensional （3-D） antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu...A full-wave analysis of the electromagnetic problem of a three-dimensional （3-D） antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu（PMCHW） approach for homogeneous dielectric objects and the electric field integral equation for conducting objects. The integral equations are discretized by the method of moment （MoM）, in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions. The resultant matrix equation is then solved by the multilevel fast multipole algorithm （MLFMA） and fast far-field approximation （FAFFA） is used to further accelerate the computation. The radiation patterns of dipole arrays in the presence of radomes are presented. The numerical results demonstrate the accuracy and versatility of this method.展开更多
A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm （FE-BI-MLFMA）. Among many algorithms of FE-BI-M...A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm （FE-BI-MLFMA）. Among many algorithms of FE-BI-MLFMA, the decomposition algorithm （DA） is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finiteelement method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor- mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality.展开更多
As the fastest integral equation solver to date, the multilevel fast multipole algorithm （MLFMA） has been applied successfully to solve electromagnetic scattering and radiation from 3D electrically large objects. Bu...As the fastest integral equation solver to date, the multilevel fast multipole algorithm （MLFMA） has been applied successfully to solve electromagnetic scattering and radiation from 3D electrically large objects. But for very large-scale problems, the storage and CPU time required in MLFMA are still expensive. Fast 3D electromagnetic scattering and radiation solvers are introduced based on MLFMA. A brief review of MLFMA is first given. Then, four fast methods including higher-order MLFMA （HO-MLFMA）, fast far field approximation combined with adaptive ray propagation MLFMA （FAFFA-ARP-MLFMA）, local MLFMA and parallel MLFMA are introduced. Some typical numerical results demonstrate the efficiency of these fast methods.展开更多
通过对三缝隙实测与多层快速多极子算法(MLFMA,Multilevel Fast Multipole Algorithm)计算曲线进行对比,证明开发的程序可用于飞行器表面不连续特征研究。采用数值方法研究了单缝隙随宽度、单台阶随高度变化的规律,分析了三缝隙板、三...通过对三缝隙实测与多层快速多极子算法(MLFMA,Multilevel Fast Multipole Algorithm)计算曲线进行对比,证明开发的程序可用于飞行器表面不连续特征研究。采用数值方法研究了单缝隙随宽度、单台阶随高度变化的规律,分析了三缝隙板、三台阶板电磁散射与其间距、极化方式之间的变化关系,并将散射结果与金属平板结果进行比较,定量总结了各参数的影响;数值结果表明,随着缝隙宽度、台阶高度的增加,不连续特征散射增强;三缝隙、三台阶的散射具有相互干涉性,且随间距的增加,曲线振荡增强。该结论可以用来提高飞行器的隐身性能。展开更多
通过单台阶、三台阶的实测与计算结果对比,证明开发的MLFMA(Multilevel Fast Multipole Algo-rithm)程序可应用于表面台阶的电磁分析。采用该算法深入研究了单台阶、三台阶电磁散射与入射频率的变化关系。结果表明,频率的增加可引起单...通过单台阶、三台阶的实测与计算结果对比,证明开发的MLFMA(Multilevel Fast Multipole Algo-rithm)程序可应用于表面台阶的电磁分析。采用该算法深入研究了单台阶、三台阶电磁散射与入射频率的变化关系。结果表明,频率的增加可引起单台阶电磁散射的增强,表现为雷达散射截面算术均值增加,单台阶的散射曲线具有一定的弱对称性;而三台阶除具有以上特性外,还表现为相互耦合性、曲线振荡增强、次波峰向内偏移、峰值增大。理论分析证明了上述结果的正确性,可以用来提高飞行器的隐身性能。展开更多
采用多层快速多极子方法(Multilevel fast multipole algorithm,MLFMA)求解混合场积分方程(Combinedfield integral equation,CFIE),并选择RWG型基函数,对金属带缝锥球体、三面角反射器以及钻石体的单站RCS(Radar cross section)进行了...采用多层快速多极子方法(Multilevel fast multipole algorithm,MLFMA)求解混合场积分方程(Combinedfield integral equation,CFIE),并选择RWG型基函数,对金属带缝锥球体、三面角反射器以及钻石体的单站RCS(Radar cross section)进行了计算,计算结果与试验吻合良好。在此基础上计算了F-22缩比模型的单站RCS,其计算量、存储量分别达到O(NlogN)量级和O(N)量级,此方法适用于带有尖点和特别细长曲面的三维复杂目标,如战斗机外形的RCS计算分析。展开更多
本文介绍了在先进高效数值方法—多层快速多极子方法(Multilevel Fast Multipole Algorithm,MLFMA)分析框架下,旨在进一步提升数值求解能力和工程应用能力的研究成果,以及结合相关成果的应用研究;重点讨论了用于超电大目标(特别是含腔目...本文介绍了在先进高效数值方法—多层快速多极子方法(Multilevel Fast Multipole Algorithm,MLFMA)分析框架下,旨在进一步提升数值求解能力和工程应用能力的研究成果,以及结合相关成果的应用研究;重点讨论了用于超电大目标(特别是含腔目标)散射分析的各型相位提取(Phase Extracted,PE)基函数、用于金属-厚介质层复合结构散射建模的电流磁流混合场积分方程(Electric and Magnetic Current Combined Field Integral Equation,JMCFIE)、用于天线罩及雷达仓散射计算的多层介质散射的多层薄介质层(Thin Dielectric Sheet,TDS)边界条件方法、用于多尺度结构电磁散射建模的快速笛卡尔展开方法;并给出了相关应用实例.最后,对当前仍然存在的主要挑战和可能的对策进行了简略的讨论和展望.展开更多
基金supported by the National Basic Research Program of China (973 Program) (61320)
文摘The method of establishing data structures plays an important role in the efficiency of parallel multilevel fast multipole algorithm（PMLFMA）.Considering the main complements of multilevel fast multipole algorithm（MLFMA） memory,a new parallelization strategy and a modified data octree construction scheme are proposed to further reduce communication in order to improve parallel efficiency.For far interaction,a new scheme called dynamic memory allocation is developed.To analyze the workload balancing performance of a parallel implementation,the original concept of workload balancing factor is introduced and verified by numerical examples.Numerical results show that the above measures improve the parallel efficiency and are suitable for the analysis of electrical large-scale scattering objects.
基金the National Natural Science Foundation of China (60431010)
文摘A full-wave analysis of the electromagnetic problem of a three-dimensional （3-D） antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu（PMCHW） approach for homogeneous dielectric objects and the electric field integral equation for conducting objects. The integral equations are discretized by the method of moment （MoM）, in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions. The resultant matrix equation is then solved by the multilevel fast multipole algorithm （MLFMA） and fast far-field approximation （FAFFA） is used to further accelerate the computation. The radiation patterns of dipole arrays in the presence of radomes are presented. The numerical results demonstrate the accuracy and versatility of this method.
文摘A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm （FE-BI-MLFMA）. Among many algorithms of FE-BI-MLFMA, the decomposition algorithm （DA） is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finiteelement method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor- mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality.
基金the National Natural Science Foundation of China (60431010, 60601008)the New CenturyExcellent Talent Support Plan of China (NCET-05-0805)+2 种基金the International Joint Research Project ("111" Project)(b07048)the"973" Programs 61360(2008CB317110)Young Doctor Displine Platform University of Electronic Science and Technology of China.
文摘As the fastest integral equation solver to date, the multilevel fast multipole algorithm （MLFMA） has been applied successfully to solve electromagnetic scattering and radiation from 3D electrically large objects. But for very large-scale problems, the storage and CPU time required in MLFMA are still expensive. Fast 3D electromagnetic scattering and radiation solvers are introduced based on MLFMA. A brief review of MLFMA is first given. Then, four fast methods including higher-order MLFMA （HO-MLFMA）, fast far field approximation combined with adaptive ray propagation MLFMA （FAFFA-ARP-MLFMA）, local MLFMA and parallel MLFMA are introduced. Some typical numerical results demonstrate the efficiency of these fast methods.
文摘通过对三缝隙实测与多层快速多极子算法(MLFMA,Multilevel Fast Multipole Algorithm)计算曲线进行对比,证明开发的程序可用于飞行器表面不连续特征研究。采用数值方法研究了单缝隙随宽度、单台阶随高度变化的规律,分析了三缝隙板、三台阶板电磁散射与其间距、极化方式之间的变化关系,并将散射结果与金属平板结果进行比较,定量总结了各参数的影响;数值结果表明,随着缝隙宽度、台阶高度的增加,不连续特征散射增强;三缝隙、三台阶的散射具有相互干涉性,且随间距的增加,曲线振荡增强。该结论可以用来提高飞行器的隐身性能。
文摘通过单台阶、三台阶的实测与计算结果对比,证明开发的MLFMA(Multilevel Fast Multipole Algo-rithm)程序可应用于表面台阶的电磁分析。采用该算法深入研究了单台阶、三台阶电磁散射与入射频率的变化关系。结果表明,频率的增加可引起单台阶电磁散射的增强,表现为雷达散射截面算术均值增加,单台阶的散射曲线具有一定的弱对称性;而三台阶除具有以上特性外,还表现为相互耦合性、曲线振荡增强、次波峰向内偏移、峰值增大。理论分析证明了上述结果的正确性,可以用来提高飞行器的隐身性能。
文摘采用多层快速多极子方法(Multilevel fast multipole algorithm,MLFMA)求解混合场积分方程(Combinedfield integral equation,CFIE),并选择RWG型基函数,对金属带缝锥球体、三面角反射器以及钻石体的单站RCS(Radar cross section)进行了计算,计算结果与试验吻合良好。在此基础上计算了F-22缩比模型的单站RCS,其计算量、存储量分别达到O(NlogN)量级和O(N)量级,此方法适用于带有尖点和特别细长曲面的三维复杂目标,如战斗机外形的RCS计算分析。
文摘本文介绍了在先进高效数值方法—多层快速多极子方法(Multilevel Fast Multipole Algorithm,MLFMA)分析框架下,旨在进一步提升数值求解能力和工程应用能力的研究成果,以及结合相关成果的应用研究;重点讨论了用于超电大目标(特别是含腔目标)散射分析的各型相位提取(Phase Extracted,PE)基函数、用于金属-厚介质层复合结构散射建模的电流磁流混合场积分方程(Electric and Magnetic Current Combined Field Integral Equation,JMCFIE)、用于天线罩及雷达仓散射计算的多层介质散射的多层薄介质层(Thin Dielectric Sheet,TDS)边界条件方法、用于多尺度结构电磁散射建模的快速笛卡尔展开方法;并给出了相关应用实例.最后,对当前仍然存在的主要挑战和可能的对策进行了简略的讨论和展望.
