guass_jodan.m

线性方程组的两个程序

function Guass_Jodan()
clc;
clear;
n=input('Input the size of the matrix:n=');
A=zeros(n,n);
A_inv=eye(n,n);
Temp=zeros(n,1);
n=3;
A=[1 1 1;0 4 -1;2 -2 1];
Temp=zeros(n,1);
A_inv=eye(n,n);
disp('The matrix you have just put is:');
A
for row=1:n-1,
    [r,max_row]=max(abs(A(row:n,row)));
    max_row=max_row+row-1;
    if(r==0),
        disp('erro!');
        return;
    end
    if(max_row~=row),
        A([row,max_row],:)=A([max_row,row],:);
        A_inv([row,max_row],:)=A_inv([max_row,row],:);
    end
    i=1:n;
    Temp(i)=A(i,row)/A(row,row);
    j=1:n;
    A(i,j)=A(i,j)-Temp(i)*A(row,j);
    A_inv(i,j)=A_inv(i,j)-Temp(i)*A_inv(row,j);
end
A
A_inv