My code is only returning the last output

Trying to un-vectorize matsum = sum(mat') and having difficulty. My code only returns the sum of the last column, any tips?

numrows = size(mat,1);
newadd = 0;
for i = 1:numrows
    vec = mat(i,end);
    for j = 1:length(vec)
        newadd = newadd + vec(j);
    end
    disp(mat)
    disp(vec)
end

Answer 1

[millercommamatt]

vec = mat(i,end);

In this line you're always using the last column by specifying end. I think you want:

vec = mat(i,:);

If I'm reading your code correctly, I think what you're ultimately looking for is:

vec = sum(mat(:));

Answer 2

[Samuele Gould]

I am not quite sure what you mean by un-vectorize, but if you want to find the sum of each column you can use the matlab function sum and specify the dimension (see the link).

The reason you are only getting the sum of the last column is because if mat is a n-by-m matrix, calling mat(i,end) will return the row i in the last column. To access all the columns you need mat(i,1:end).

numrows = size(mat,1);
newadd = 0;
for i = 1:numrows
    vec = mat(i,end);
    for j = 1:length(vec)
        % returns the sum of all the elements of the matrix
        newadd = newadd + vec(j);
    end
    disp(mat)
    disp(vec)
end