Parfor loop for saving data

Hi, I needed to know if the next loop can be implemented using a parfor, because if I do that I get an error.

What I need is to store in the first column the time, in the second the psnr and in the third in snr for each of the 4 images.

Z = zeros(50,3,4);
parfor idx = 1 : 4
    I = cargarDatos(idx);
    for noise = 1 : 100
        if isequal(mod(noise,2),1)
            tic
            J = medfilt2(I,[noise noise])
            Z(r,1,idx) = toc;
            [Z(r,2,idx),Z(r,3,idx)] = psnr(J,I4);
            r = r + 1;
        end
    end
end

The "cargarDatos" function allows to upload the images in question

[Edric Ellis]

Where are you defining r? As written, this loop is not compatible with parfor because it appears as though the iterations are order-dependent (because of r).

[Alejandro Fernández]

Yes you are right, I forgot to define r in the loop, but it still doesn't work, it still gives me error

Z = zeros(50,3,4);
parfor idx = 1 : 4
    I = cargarDatos(idx);
    r = 1;
    for noise = 1 : 100
        if isequal(mod(noise,2),1)
            tic
            J = medfilt2(I,[noise noise])
            Z(r,1,idx) = toc;
            [Z(r,2,idx),Z(r,3,idx)] = psnr(J,I4);
            r = r + 1;
        end
    end
end

[Sindar]

what error?