function calc_error(data, pred)

	quad = quad_error(data, pred);
	total = total_error(data, pred);

	printf('quad mean     : %9d\n', quad);
	printf('total mean    : %9d\n', total);

	plot((sum(abs(data - pred))), 'b');
	hold on;
	plot(sort(sum(abs(data - pred))), 'r');
	hold off;
end