how can i find the sum of matrix elements

if i have a two dimension matrix i want to create a for loop to compute the summation of element in this matrix like : sum= 0 for i=1 to n for j= 1 to m sum= sum + a[j,j] but in matlab!!!

Answer 1

[Azzi Abdelmalek]

You can use sum function

sum(A(:))

Answer 2

[Star Strider]

If you want to sum the diagonal elements of a, I suggest:

a = rand(5,5);
sd = sum(diag(a));

Do not use sum as a variable name. It is a built-in MATLAB function, and using it as a variable name will cause problems later in your code.

If you want the sum of all the elements in your matrix, I suggest:

sa = sum(a(:));