approximation methods in physics

Some numerical methods such as, Pade rational approximation method,Marching and bidirectional beam propagation method which are used to solveHelmhotlz equation are compared in this paper.

本文就几种解亥姆霍兹(Helmhotlz)方程的数值方法：Pade有理逼近法、Marching步进法以及双向光束传播法进行比较，并着重介绍了一种有效的双向光束传播法在光栅中的应用。

Analyzing the main factors affecting the importance of the position,get the numerical value of the factors by Delphi method,get the factors weight by AHP method,and gives the sequencing criterions by using TOPSIS method.

分析了影响阵地重要性的主要因素,采取德尔菲法获得指标值,采用层次分析法得到指标权重,利用逼近理想解的排序法对待选阵地的优劣进行了定量分析。