static L<Int> localMaximaIncludingPlateaus(double[] l) {
  new L<Int> out;
  int n = l(l);
  for i to n:
    if ((i == 0 || l[i] >= l[i-1])
      && (i == n-1 || l[i] >= l[i+1]))
      out.add(i);
  ret out;
}