spot.setValue(u + du);
final double value_p = option.NPV();
final double delta_p = option.delta();
spot.setValue(u - du);
final double value_m = option.NPV();
final double delta_m = option.delta();
spot.setValue(u);
expected.put("delta", (value_p - value_m) / (2 * du));
expected.put("gamma", (delta_p - delta_m) / (2 * du));
/*