Question

Write a function which takes as input a matrix and outputs a matrix in which each positive element is doubled. For instance, for the matrix A=[3, -1; -2, 4], and output should be [6,-1; -2,8].

Answer 1

function [result] = doublePositives(v)
    [r, c] = size(v);
    result = [];
    for i=1:r
        for j=1:c
            if v(i, j) > 0
                result(i, j) = 2*v(i, j);
            else
                result(i, j) = v(i, j);
            end
        end
    end
end


A=[3, -1; -2, 4]
doublePositives(A)