中文摘要：

为了提高多层快速多极子算法求解电磁散射问题的效率,提出了两种修正多极子模式数的方法。与传统的多层快速多极子相比,该方法通过有效地减少多极子模式数,从而减少了迭代求解矩阵方程时的矩矢相乘时间和内存存储需求。计算结果表明,该方法提高了电磁散射问题求解的计算效率,保留了原有方法的精度,同时保持了多层快速多极子算法的计算复杂度,并且简单易于实现,十分适于三维电大结构电磁散射问题的求解。

英文摘要：

In order to improve the efficiency of solving electromagnetic scattering problems by the multilevel fast multipole algorithm（MLFMA）,two novel strategies are proposed to determine the multipole numbers.Comparing with traditional MLFMA,through reduction of the multipole numbers,the proposed methods can reduce CPU time in the iteration and the memory requirement.Numerical results show that the modified methods improve the efficiency of solution while retaining the high accuracy and the complexity of O（Nlog N） for the computation of matrix-vector multiplication by MLFMA.This is why it is suitable for electromagnetic scattering problems of 3D electrically large structures.