function grd = mkr(grd,konfs,delim,eps)
%
% Metoda koncnih razlik, splosno
% grd = grid
% grd(i,j) = delim^(-1) * konfs(1)*grd(i-1,j)+konfs(2)*grd(i+1,j)+konfs(3)*grd(i,j-1)+konfs(4)*grd(i,j+1)
% while diferenca norme < eps vrti...
%
  [n,m] = size(grd);
  for k=1:1000
    prev=grd;
    for i=2:n-1,
      for j=2:m-1,
        grd(i,j) = (konfs(1) * grd(i-1,j) + konfs(2) * grd(i+1,j) + konfs(3) * grd(i,j-1) + konfs(4) * grd(i,j+1)) /delim;
      end;
    end;
    if abs(grd-prev)<eps, break, end;
  end;
end;

function grd = mkrLaplace(grd, eps = 1e-5)
  grd = mkr(grd, [1,1,1,1], 4, eps);
end;