Finally the paper emphatically introduces the mlfma ( multilevel fast multipole algorithm ) . based on hybrid field integral equation the formulation of computation for the electromagnetic scattering of three - dimensional object is derivated . then the optimization of invariant terms and the expression of every child cube is analyzed during the electromagnetic scattering calculation when using the mlfma 文章最后引入多层快速多极子法，从混合场的积分方程出发，推导出多层快速多极子法计算三维物体电磁散射的公式，分析了多层快速多极子法计算三维物体电磁散射过程中不变项计算的优化和编程时每个小立方体的表示方法。
