Analysis by SBC

392

Name	정오연

Subject	정오연

% gauss_el.m
% Programmed by 정오연

function x = gauss_el(A,b);
n = length(A);
R = [A b];

for j=1:n-1
    for i=j+1:n
        if R(j,j)==0
            max_id = find( max( abs(R(j+1:n,j)) ) ) + j; % Find pivot
            temp = R(j,:);  % Change two rows
            R(j,:) = R(max_id,:);  R(max_id,:) = temp;
        end
        a = R(i,j)/R(j,j);
        R(i,:) = R(i,:) - a*R(j,:);
    end
end
A = R(:,1:n); b = R(:,n+1);
x = zeros(n,1);
for j=n:-1:1
    x(j) = ( b(j) - A(j,j+1:n)*x(j+1:n) )/A(j,j);
end
norm( b-A*x )

%%%%

>> A = myrand(8,8,1,10); b = myrand(8,1,10,20)

b =

    18
    17
    13
    13
    13
    15
    17
    13

>> x = gauss_el(A,b)

ans =

  5.4208e-015

x =

   15.0090
  -10.8279
   -0.2582
   15.3240
   -0.9018
   -5.3352
   -7.2939
    1.9774

>>

DATE: 2013.10.10 - 15:17

gauss_el.m

gauss_el