differenceND function

List<double> differenceND(
  1. List<double> x,
  2. int d,
  3. int s,
  4. int D,
)

Combined differencing: ordinary then seasonal (order doesn't matter since they commute)

Implementation

List<double> differenceND(List<double> x, int d, int s, int D) {
  var y = differenceOrdinary(x, d);
  y = differenceSeasonal(y, s, D);
  return y;
}