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FEKO中为MLFF法划分的网格是什么类型网格？
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我是新手。
请问：FEKO中MLFMM法所需要的网格，是什么方法生成的?是什么网格?是非结构网格吗?
有知道的麻烦告诉一下，谢谢了
http://www.feko.info/feko-product-info/technical/mlfmm
The MLFMM is an alternative formulation of the technology behind the MoM and is applicable to much larger structures than the MoM, making full-wave current-based solutions of electrically large structures a possibility. This fact implies that it can be applied to most large models that were previously treated with the MoM without having to change the mesh.
Technical Foundation
The agreement between the MoM and MLFMM is that basis functions model the interaction between all triangles. The MLFMM differs from the MoM in that it groups basis functions and computes the interaction between groups of basis functions, rather than between individual basis functions. FEKO employs a boxing algorithm that encloses the entire computational space in a single box at the highest level, dividing this box in 3 dimensions into a maximum of 8 child boxes and repeating the process iteratively until the side length of each child box is approximately a quarter wavelength at the lowest level. Only populated boxes are stored at each level, forming an efficient tree-like data structure. In the MoM framework the MLFMM is implemented though a process of aggregation, translation and disaggregation of the different levels.
The MoM treats each of the N basis functions in isolation, thus resulting in an N2 scaling of memory requirements (to store the impedance matrix) and N3 in CPU-time (to solve the linear set of equations). It is thus clear that processing requirements for MoM solutions scale rapidly with increasing problem size. The MLFMM formulation's more efficient treatment of the same problem results in N.log(N) scaling in memory and N.log(N).log(N) in CPU time. In real applications this reduction in solution requirements can range to orders of magnitude.
Significant effort has also been invested in improving the parallel MLFMM formulation to achieve exceptionally high efficiency when distributing a simulation over multiple processors.
http://www.feko.info/overview-of-feko
Numerical methods
The FEKO solver is based on the Method of Moments (MoM) and was the first commercial code to utilise the multi-level fast multipole method (MLFMM) for the solution of electrically large problems when it was released with Suite 4.2 in June 2004. In FEKO, the MoM is hybridised with the following solution techniques:
Finite Element Method (FEM)
Physical Optics (PO)
Geometric Optics (GO) based on ray launching
Uniform Theory of Diffraction (UTD)
This hybridisation implies that these solution techniques can be applied to different parts of the same model to optimise the solution time and results.
请问：FEKO中MLFMM法所需要的网格，是什么方法生成的?是什么网格?是非结构网格吗?
有知道的麻烦告诉一下，谢谢了
MLFMM是来大量降低记忆体
Aggregation, translation and disaggregation
http://www.feko.info/feko-product-info/technical/mlfmm
The MLFMM is an alternative formulation of the technology behind the MoM and is applicable to much larger structures than the MoM, making full-wave current-based solutions of electrically large structures a possibility. This fact implies that it can be applied to most large models that were previously treated with the MoM without having to change the mesh.
Technical Foundation
The agreement between the MoM and MLFMM is that basis functions model the interaction between all triangles. The MLFMM differs from the MoM in that it groups basis functions and computes the interaction between groups of basis functions, rather than between individual basis functions. FEKO employs a boxing algorithm that encloses the entire computational space in a single box at the highest level, dividing this box in 3 dimensions into a maximum of 8 child boxes and repeating the process iteratively until the side length of each child box is approximately a quarter wavelength at the lowest level. Only populated boxes are stored at each level, forming an efficient tree-like data structure. In the MoM framework the MLFMM is implemented though a process of aggregation, translation and disaggregation of the different levels.
The MoM treats each of the N basis functions in isolation, thus resulting in an N2 scaling of memory requirements (to store the impedance matrix) and N3 in CPU-time (to solve the linear set of equations). It is thus clear that processing requirements for MoM solutions scale rapidly with increasing problem size. The MLFMM formulation's more efficient treatment of the same problem results in N.log(N) scaling in memory and N.log(N).log(N) in CPU time. In real applications this reduction in solution requirements can range to orders of magnitude.
Significant effort has also been invested in improving the parallel MLFMM formulation to achieve exceptionally high efficiency when distributing a simulation over multiple processors.
http://www.feko.info/overview-of-feko
Numerical methods
The FEKO solver is based on the Method of Moments (MoM) and was the first commercial code to utilise the multi-level fast multipole method (MLFMM) for the solution of electrically large problems when it was released with Suite 4.2 in June 2004. In FEKO, the MoM is hybridised with the following solution techniques:
Finite Element Method (FEM)
Physical Optics (PO)
Geometric Optics (GO) based on ray launching
Uniform Theory of Diffraction (UTD)
This hybridisation implies that these solution techniques can be applied to different parts of the same model to optimise the solution time and results.
楼上的能不能用中文回答，而且不要写与所问无关的内容?谢谢！
仍然是MOM法的网格刨分
jimliu12，你好，我知道是MOM法的，我想问的是网格用什么方法生成的?是什么网格?是非结构网格吗? 谢谢
多层快速多级子算法网格也是表面网格
里面有个多层的概念，似乎要划分体网格，以前一直隐约觉得多层快速多级子要比巨量法多划分体网格的，因为里面有个多层的概念，一般教科书上也给出体网格的示意图。其实不是。今天翻了一下盛兴庆那本书，基本搞明白了：
多层快速多级子中那个体网格的示意图实际意思是指：在表面网格外面套一个长方体，然后切割成若干个小长方体（第一层），这样不同表面网格归属不同的小长方体，同一个小长方体内的网格进行聚集－转移之类的操作。
当然还可以继续对长方体细分，就有了好几层的概念，也是研究不同表面网格归属那一层的盒子
因此MLFMM那个盒子作用是确定表面网格属于那一层的长方体中，而不是CFD或者有限元中的体网格的概念。长方体的划分和表面网格的归属都很简单，只需要编程时加入该子程序，（只需要判断表面网格是否在盒子中就可以判断归属关系），不需要我们划分体网格
不知上面的解释小编是否理解?简而言之:MLFMM只需要划分表面网格就行了，通常是三角形面网格，不需要结构网格或者非结构网格（那一般指体网格）
上传一张图，就是多层网格的剖分示意图，明确多层的用途只是确定表面网格属于那一层哪一个盒子中这个核心思想，你就明白不需要划分体网格了
谢谢5楼(jetwolf)的回答。 请问盛兴庆的哪本书对MLFMM讲得比较清楚?PS：FEKO切分的网格应该属于非结构化网格吧，因为听说体网格也是先要生成面网格再生成体网格的，对吗?谢谢
盛兴庆的《计算电磁学概论》讲的比较通俗一些
非结构化网格和结构网格都是体网格，非结构网格一般是先划分表面网格，再生成体网格；结构网格不需要划分表面网格就可以生成
FEKO里面是面网格，因为矩量法是表面积分方程，所以不需要体网格
我费了不少口水给你解释，只是说明我以前的一个认识上的误区：多层似乎要划分体网格，其实不需要的
所以你研究多层快速多级子算法，不会用到非结构网格的
不好意思，还要问你一下，请问是ＦＥＫＯ中的表面网格属于什么类型的表面网格呢?因为，我要写论文，想写一下。麻烦你了。
另外，你说的盛兴庆的《计算电磁学要论》，我在网上书店看了内容介绍，没有关于ＭＬＦＭＭ的，帮忙确定一下，哪本书有比较详细的介绍，谢谢了。
这本书不错，介绍中没写有MLFMM，但里面有相关内容，谢谢了。
网格当然是结构性的，表征实际结构的，将实际的物体离散化，然后通过maxwell的电场方程计算每个网格单元的表面电流，求得电场～～
FEKO是三角形网格～～采用RWG基函数～～
