来个好心人帮我解释下这个matlab程序吧 详细的重赏！！！

function u=gauss(a,n)for k=1:n-1 for i=k+1:n for j=k+1:n+1 if abs(a(k,k))>1e-6 a(i,j)=a(i,j)-a(i,k)/a(k,k)*a(k,j); else msgbox('Gauss消去失败','计算结果'); pause; exit; end end endendx(n)=a(n,n+1)/a(n,n);for i=n-1:-1:1 s=0; for j=i+1:n s=s+a(i,j)*x(j); end x(i)=(a(i,n+1)-s)/a(i,i);endu=x;