function [x,k]=my_sor(a,b,x0,w,tol,kmax)

n=length(b);

error = 1000; x=x0;

k = 0;
while error > tol & k < kmax
  for i=1:n
     x_temp =  b(i);
     for j=1:n
	if( j~= i) 
           x_temp = x_temp - a(i,j)*x(j);
	end
     end
     x_temp = x_temp/a(i,i);
     x(i) =  (1-w)*x0(i) + w*x_temp;
  end

  error = max(max(abs(x-x0)))
  x0 = x;
  k = k+1;
end

return