public T[][] derivatives(T x, int order) throws NoDataException, NullArgumentException {
// safety check
MathUtils.checkNotNull(x);
if (abscissae.isEmpty()) {
throw new NoDataException(LocalizedFormats.EMPTY_INTERPOLATION_SAMPLE);
}
final T zero = x.getField().getZero();
final T one = x.getField().getOne();
final T[] tj = MathArrays.buildArray(x.getField(), order + 1);