static double absDoubleMax(Iterable<Double> l) {
  double max = -Double.MAX_VALUE;
  fOr (double d : l)
    max = Math.max(max, abs(d));
  ret max;
}

static double absDoubleMax(double[] l) {
  double max = -Double.MAX_VALUE;
  fOr (double d : l)
    max = Math.max(max, abs(d));
  ret max;
}

static double absDoubleMax(double[] l, int from, int to) {
  double max = -Double.MAX_VALUE;
  for (int i = from; i < to; i++)
    max = Math.max(max, abs(l[i]));
  ret max;
}