# Line 37: Parse error at A: usage might be invalid MATLAB syntax.

3 vues (au cours des 30 derniers jours)
Abul Yasa Hasan le 16 Mar 2024
Commenté : Abul Yasa Hasan le 16 Mar 2024
Ques.) Use Householder's method to place the following matrices in tridiagonal form.
I had a basic code provided by the tutor which I adapted to the problem above. However, when I run the I get the error in Line 37(the second last line) - Parse error at A: usage might be invalid MATLAB syntax.
% Test with the given matrix
A = [4.75 2.25 -0.25; 2.25 4.75 1.25; -0.25 1.25 4.75];
hh_tridiag(A);
alpha = -2.2638, r = 2.2604, w = 0 0.99847 -0.0553 P^(1) = 1.0000 0 0 0 -0.9939 0.1104 0 0.1104 0.9939 A^(2) = 4.7500 -2.2638 -0.0000 -2.2638 4.4756 -1.2195 -0.0000 -1.2195 5.0244
function hh_tridiag(A)
n = size(A, 1);
for k = 1:(n-2)
% Calculate t and alpha
t = sqrt(sum(A((k+1):end, k).^2));
if A(k+1, k) ~= 0
alpha = -sign(A(k+1, k)) * t;
else
alpha = -t;
end
% Calculate r and w
r = sqrt((alpha^2 - A(k+1, k) * alpha) / 2);
w = zeros(n, 1);
w(k+1) = (A(k+1, k) - alpha) / (2 * r);
for j = (k+2):n
w(j) = A(j, k) / (2 * r);
end
disp(['alpha = ', num2str(alpha), ', r = ', num2str(r), ', w = ', num2str(w')]);
% Calculate Householder matrix P
P = eye(n) - 2 * (w * w');
disp(['P^(', num2str(k), ') =']);
disp(P);
% Update A
A = P * A * P';
disp(['A^(', num2str(k+1), ') =']);
disp(A);
end
end
##### 2 commentairesAfficher AucuneMasquer Aucune
Dyuman Joshi le 16 Mar 2024
The code runs without any error (see the edit above).
Make sure if you are running this as a script, the function is placed at the bottom of the script.
Abul Yasa Hasan le 16 Mar 2024
Thank You!

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