gausselimination1111.m

雅克比迭代法 求Hilbert矩阵病态方程组

clear;
n=input('n=');
x=hilb(n); y=ones(n,1);
z=x*y;
augm=[x z];       
for i=1:n-1
    if augm(i,i)==0   
        k=i+1;        
        while augm(k,i)==0&k<=n
            k=k+1;
        end
        b=augm(i,:); augm(i,:)=augm(k,:); augm(k,:)=b;
    end
    for j=i+1:n         
        augm(j,:)=augm(j,:)-augm(j,i)/augm(i,i).*augm(i,:);
    end
end
augm,                  
x(n)=augm(n,n+1)/augm(n,n);     
for i=n-1:-1:1                  
    b=0;
    for j=n:-1:i+1
        b=b+x(j)*augm(i,j);
    end
    x(i)=(augm(i,n+1)-b)/augm(i,i);
end
x,