I have to calculate the eigen vector and eigenvalues & i write a code and use the eig() function but it shows some error such as Undefined function 'eig' for input arguments of type 'double' and attributes 'full 3d real', please help.Code are below

    Matrix = imread('uz.jpg');

%Convert image to double precision to use eig function:

    imtype = class(Matrix);
    Matrix = double(Matrix);

%Find a square matrix that fits image for eig operation:

    sz = size(Matrix);
    m = max(sz);
    mx = zeros(m, m,3);
    mx(1:sz(1),1:sz(2),1:sz(3)) = Matrix

%Find eigenvectors and eigenvalues:

    [V, D] = eig(mx)

%check that the matrix generates A using matrix factorization and convert back to original image:

    eval(['A = ',imtype,'(abs(V*D*V^(-1)));']);
    figure
    imshow(A)

[Image Analyst]

You don't need eval() and class() to compute and cast A. Using eval() is not recommended. Just use cast():

A = cast(someMatrixToConvert, class(Matrix));

Answer 1

[Star Strider]

Your mx matrix is 3-dimensional. You can only take eigenvalues and eigenvectors of a square (NxN) matrix.

[John D'Errico]

The point is, you need to think about what it you intend when you try to compute the eigenvalues of an image. There are three channels in an image. Until you decide what you are trying to do, and think about how you must approach it in a way that is mathematically valid, eig will/must fail.

[Stephen23]

To this end it could be worth revising the definition of eigenvectors and eigenvalues, and then think about the code: understanding the problem is just as important as solving it.