《计算方法》Fortran版.docx

第一章：线性方程组的解法一、矩阵分解与线性方程组直接方法1.LU分解解方程moduleLU!modulecoment!Version!Codedby:syz!Date!Description:LU分解解方程!containssubroutinesolve(A,b,x,N)implicitreal*8(a-z)integer:Nreal*8:A(N,N),b(N),x(N)real*8:L(N,N),U(N,N)real*8:y(N)calldoolittle(A,L,U,N)calldowntri(L,b,y,N)calluptri(U,y,x,N)endsubroutinesolvesubroutinedoolittle(A,L,U,N)!subroutinecomment!Version:!Codedby:syz!Date!Purpose:LU分解之Doolittle函数!A=LU!Inputparameters1.A方阵