列主元.txt

数值计算方法的一些题

function [X,det]=myGauss(A)   %列主元
    sign=1;
    [n,m]=size(A);
    if n~=m-1
        'error'
        break
    end
    for k=1:n-1
        [l,m]=max(abs(A(k:n,k)));
        if A(k+m-1,k)==0
           'error'
           break
        end
        if m~=1
        T=A(k,:);
        A(k,:)=A(k+m-1,:);
        A(k+m-1,:)=T;
        sign=-sign;
        end
        for i=k+1:1:n
            A(i,:)=A(i,:)-A(k,:)*A(i,k)/A(k,k);
        end
        if A(n,n)==0
            'error'
            break
        else X(n)=A(n,n+1)/A(n,n);
        end
       for k=n-1:-1:1
             X(k)=(A(k,n+1)-dot(A(k,k+1:n),X(k+1:n)))/A(k,k);
         end
    end
    det=A(1,1);
    for i=2:n
        det=det*A(i,i);
    end