differenceSeas function

List<double> differenceSeas(
  1. List<double> x,
  2. int s,
  3. int D
)

Seasonal differencing

Implementation

List<double> differenceSeas(List<double> x, int s, int D) {
  if (D <= 0 || s <= 1) return List<double>.from(x);
  var y = List<double>.from(x);
  for (int k = 0; k < D; k++) {
    final n = y.length;
    final z = <double>[];
    for (int i = s; i < n; i++) z.add(y[i] - y[i - s]);
    y = z;
  }
  return y;
}