How to convert matrices of different sizes in a for loop into a single column vector?

A = imread('Ish.JPG');
A = im2single(squeeze(mean(A,3)));
A = im2double(A);
[pyrRef,pind] = buildLpyr(A,'auto');
nLevels = 7;
kernelx = [0.0, 0.0, 0.0; 0.5, 0.0, -0.5; 0.0, 0.0, 0.0];
kernely = [0.0, 0.5, 0.0; 0.0, 0.0, 0.0; 0.0, -0.5, 0.0];
for k = 1:nLevels
    subband = pyrBand(pyrRef, pind, k);
    rx(k) = conv2(subband(k),kernelx);
    ry(k) = conv2(subband(k),kernely);
    amp = sqrt(subband.^2 + rx(k).^2 + ry(k).^2);
    Phase = acos(subband./amp);
end

Here, the value of "Phase" is a matrix with varying dimension at each iteration of 'k'. How do I save all the values in these k matrices into a single coloumn vector?

[Jiri Hajek]

Hi, you can make column vector from a matrix by using linear indexing

columnVector = Array(:);

And if by "save all" you mean to concatenate these vectors, then its possible simply by using brackets:

concatenatedVectors = [firstVector; secondVector];

[Anisia Anil]

by "save all" I meant, I want to save all k number of matrices into a sigle coloumn vector.

Answer 1

[Jan]

...
PhaseC = cell(1, nLevels);
for k = 1:nLevels
    ...
    PhaseC{k} = acos(subband./amp);
end
Phase = cat(2, PhaseC{:});  % Maybe cat(1, ...

Answer 2

[MFK]

https://www.mathworks.com/help/matlab/ref/reshape.html

for k = 1:nLevels
    ...
    Phase = acos(subband./amp);
    re_shaped_Phas{k,1}=reshape(Phase,1,[]);
end

Answer 3

[Bruno Luong]

...
PhaseC = cell(1, nLevels);
for k = 1:nLevels
    ...
    Phase = acos(subband./amp);
    PhaseC{k} = Phase(:);
end
Phase = cat(1, PhaseC{:});