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 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
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...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
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
对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole...对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole Algorithm,MLFMA)计算曲线进行对比,验证了程序的正确性,说明其可用于飞行器表面不连续特征研究。采用数值方法详细研究了单缝隙、三缝隙电磁散射与入射电磁波频率的变化关系。数值计算结果表明,入射电磁波频率增加时,对单缝隙,电磁散射增强,雷达散射截面算术均值增加,其中掠入射角域内的均值增加最为明显;同时单缝隙的散射曲线相似、次波峰向外偏移;对三缝隙,除具有单缝隙的特性外,还表现为相互耦合性、曲线振荡增强,通过分析认为3个单缝隙散射不同相位的相互叠加导致了其散射的耦合性,入射频率增加时,散射叠加的峰值位置发生相应变化,表现为耦合作用和振荡作用更加明显。该结论可以用来进行飞行器表面的缝隙散射的减缩设计,从而有效提高飞行器的隐身性能。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
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.
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)
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.
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.
文摘对隐身飞行器、坦克等武器系统,缝隙等不连续特征对RCS的减缩和控制具有重要影响。基于混合场积分方程,开发出了多层快速多极子算法程序,通过将金属球双站RCS级数解、三缝隙实测曲线分别与多层快速多极子算法(Multilevel Fast Multipole Algorithm,MLFMA)计算曲线进行对比,验证了程序的正确性,说明其可用于飞行器表面不连续特征研究。采用数值方法详细研究了单缝隙、三缝隙电磁散射与入射电磁波频率的变化关系。数值计算结果表明,入射电磁波频率增加时,对单缝隙,电磁散射增强,雷达散射截面算术均值增加,其中掠入射角域内的均值增加最为明显;同时单缝隙的散射曲线相似、次波峰向外偏移;对三缝隙,除具有单缝隙的特性外,还表现为相互耦合性、曲线振荡增强,通过分析认为3个单缝隙散射不同相位的相互叠加导致了其散射的耦合性,入射频率增加时,散射叠加的峰值位置发生相应变化,表现为耦合作用和振荡作用更加明显。该结论可以用来进行飞行器表面的缝隙散射的减缩设计,从而有效提高飞行器的隐身性能。
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。
