测试划行划列的结果

function  [x]=testRL(A,b)
%%测试删除一行一列的结果
%u=sin(3*pi*x+pi/4)*sin(2*pi*y+pi/4)
delta_y=1.0/(sqrt(length(A))-1);
for i=1:sqrt(length(A)):length(A)
    x(i)=sin(3*pi*0+pi/4)*sin(2*pi*delta_y*(i-1)+pi/4);
    for j=1:length(A)
        A(i,j)=0;
    end
        A(i,i)=1;
    b(i)=x(i);
end
% for i=1:length(A)
%     for j=1:length(A)/2
%     AA()
%B=A(;,length(A)-1)
x=gmres(A,b);
disp(A);
disp(b');
% bb=A*x
% norm(bb-b)

A=[2 3 4 5;4 3 2 6;7 3 5 3;5 4 2 6]
b=[5 6 7 8]