Thank you all for the reply. I already solved, in part, the problem I had, but now I have another. I have this line of code:
where 'MK_G', num2str (px (j, 1)) are N number of matrices that are already created. but I require, in some way, that the intervals of the matrix that I am evaluating (in this case 4: 6,4: 6) are in some way variable. I thank you for your collaboration with this new problem.