function s = mySum( n )
% ===================================================
% Purpose: This function computes the sum from 1 to n.
% Syntax:  s = mySum( n )
% Inputs:  n = integer
% Output:  s = result of summation
% ===================================================

  % Initialize variable
  s = 0;

  % Check if number is positive
  if ( n < 1 )  
     return;
  else
     % Accumulate values
     for i = 1:n
       s = s + i;
     end
  end