Transform matrix into vector X Y Z

Hi!

I have a matrix 1024 * 1024 and I need to do a regression with this matrix, but first I need to convert it to a X Y Z vector for example.

2 2 3

1 5 7

9 8 7

Where X = n, Y = m, and Z = value, in order to get the vectors in this form

(1 , 1, 2)

(1 , 2 , 2)

(1, 3, 3)

(2, 1, 1)

(2, 2, 5) , etc

Thank you for your help

Answer 1

[KSSV]

You may follow something like this:

A = [2   2   3
1   5   7
9   8   7];

[m,n] = size(A) ; 

[X,Y] = meshgrid(1:n,1:m) ; 

P = [X(:) Y(:) A(:)]

[Fernando Lobo]

Thank you very much!

Answer 2

[Walter Roberson]

A = [
    2   2   3
    1    5   7
    9   8   7]

A = 3×3

2 2 3 1 5 7 9 8 7

[X, Y, Z] = find(A);
XYZ = sortrows([X, Y, Z])

XYZ = 9×3

1 1 2 1 2 2 1 3 3 2 1 1 2 2 5 2 3 7 3 1 9 3 2 8 3 3 7

Note: this particular implementation does not output 0. If you need 0 then a different implementation would be used.