有限元编程,本程序包含四个子程序，其主要功能分别是：

void matmat void matvec

调用结点及单元信息判断并循环形成总刚

double matvec double gs

调用结点位移及结点信息和对应单元信息，回代求出并输出单元杆端力

-Finite element programming, the program contains four subroutines, the main functions are:

Void matmat void

Call the node and unit information to determine and cycle the formation of the total just

Double matvec double gs

Call node displacement and node information and the corresponding unit information, back to generation and output unit rod end force