function [L,U,x]=zgf(A,b)%行趕法的件矩A為對(duì)角矩陣,且矩陣A為嚴(yán)對(duì)角占優(yōu),因?yàn)檫@樣才能使除數(shù)不為零,這樣才會(huì)使計(jì)算不回中止,即不會(huì)產(chǎn)生[n,m]=size(A);for i=1:n    if i==1        if abs(A(1,1))>abs(A(1,2))            k=1;        else            k=0;            disp('此矩陣不為嚴(yán)格對(duì)角占優(yōu)矩陣');            break;        end    elseif i==n        if abs(A(n,n))>abs(A(n,n-1))            k=1;        else            k=0;            disp('此矩陣不為嚴(yán)格對(duì)角占優(yōu)矩陣');            break;        end    else        if abs(A(i,i))>=abs(A(i,i-1))+abs(A(i,i+1))            k=1;        else            k=0;            disp('此矩陣不為嚴(yán)格對(duì)角占優(yōu)矩陣');            break;        end    endendif k==1    L(1,1)=A(1,1);    U=diag(ones(1,n));    U(1,2)=A(1,2)/L(1,1);    for l=2:n        L(l,l-1)=A(l,l-1);    end    for l=2:n        L(l,l)=A(l,l)-A(l,l-1)*U(l-1,l);        if l~=n            U(l,l+1)=A(l,l+1)/L(l,l);        end    endendy(1)=b(1)/L(1,1);for i=2:n    y(i)=(b(i)-L(i,i-1)*y(i-1))/L(i,i);endx(n)=y(n);for i=n-1:-1:1    x(i)=y(i)-U(i,i+1)*x(i+1);end