sum all columns in a matrix

hi,

i want to sum all the columns of some matrix.

but without using a loop or the sum function.

for ex:

for the matrix [1 3 2; 4 4 8]

i will recive [5 7 10]

Answer 1

[James Tursa]

Hint: Look at matrix multiplication.

Answer 2

[Maneet Kaur Bagga]

Hi Ariela Glikman

As per my understanding you want to get the sum of the matrix coloumn wise so you can use the MATLAB sum function. All the MATLAB functions by default work on coloumn so you get the sum directly. You can refer to the code below. Hope it helps!

x = [1 3 2; 4 4 8]

x = 2×3

1 3 2 4 4 8

sum(x)

ans = 1×3

5 7 10

[DGM]

In any practical scenario, using sum() would be perfectly sensible, but OP was working around contrived limitations -- no loops and no sum().

[Maneet Kaur Bagga]

Thanks for correcting DGM,

You can refer to the below code as a solution.

x1 = [1 2 3; 4 5 6; 7 8 9];
  all =(x1);
sumcol=0;
    for i=1:length(all)
       sumcol = 0;
       for j = 1:length(all)
            sumcol = sumcol + all(j,i);
       end 
        fprintf("%d ",sumcol);
    end

12 15 18