function [uxct f] = calc_exact(omega_x, omega_y, n, h)
%  calc_exact:  Calculates exact function values and corresponding r.h.s.
%  for model problem.  
for i = 1 : n
   for j = 1 : n
      uxct(i,j) = sin(omega_x * (i - 1) * h) * sin(omega_y * (j - 1) * h);
      f(i,j) = -(omega_x^2 + omega_y^2) * uxct(i,j);
   end
end
