public static int compare(double a, double b) {
    return Double.compare(a, b);
  }

  /**
   * Returns {@code true} if {@code value} represents a real number. This is equivalent to, but not
   * necessarily implemented as, {@code !(Double.isInfinite(value) || Double.isNaN(value))}.
   *
   * <p>Prefer {@link Double#isFinite(double)} instead.
   *
   * @since 10.0
   */

    testRotate(new double[] {}, -1, new double[] {});
    testRotate(new double[] {}, 0, new double[] {});
    testRotate(new double[] {}, 1, new double[] {});

    testRotate(new double[] {1}, -2, new double[] {1});
    testRotate(new double[] {1}, -1, new double[] {1});
    testRotate(new double[] {1}, 0, new double[] {1});
    testRotate(new double[] {1}, 1, new double[] {1});
    testRotate(new double[] {1}, 2, new double[] {1});

    SIMPLE {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        for (double value : values) {
          sum += value;
        }
        return sum / values.length;
      }
    },
    KAHAN {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        double c = 0.0;
        for (double value : values) {
          double y = value - c;

    SIMPLE {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        for (double value : values) {
          sum += value;
        }
        return sum / values.length;
      }
    },
    KAHAN {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        double c = 0.0;
        for (double value : values) {
          double y = value - c;

    testRotate(new double[] {}, -1, new double[] {});
    testRotate(new double[] {}, 0, new double[] {});
    testRotate(new double[] {}, 1, new double[] {});

    testRotate(new double[] {1}, -2, new double[] {1});
    testRotate(new double[] {1}, -1, new double[] {1});
    testRotate(new double[] {1}, 0, new double[] {1});
    testRotate(new double[] {1}, 1, new double[] {1});
    testRotate(new double[] {1}, 2, new double[] {1});

  private static final double[] VALUES = {
    Double.NEGATIVE_INFINITY,
    -Double.MAX_VALUE,
    (double) Long.MIN_VALUE,
    (double) Integer.MIN_VALUE,
    -Math.PI,
    -1.0,
    -Double.MIN_VALUE,
    -0.0,
    +0.0,
    Double.MIN_VALUE,
    1.0,
    Math.PI,
    (double) Integer.MAX_VALUE,
    (double) Long.MAX_VALUE,
    Double.MAX_VALUE,
    Double.POSITIVE_INFINITY,

          Doubles.asList(
              -Double.MIN_VALUE,
              -Double.MIN_NORMAL,
              -1,
              -20,
              Double.NaN,
              Double.NEGATIVE_INFINITY,
              -0.001));

  public void testFuzzyEqualsFinite() {
    for (double a : FINITE_DOUBLE_CANDIDATES) {
      for (double b : FINITE_DOUBLE_CANDIDATES) {

      Double[] suffix = {86.0, 99.0};
      Double[] all = concat(concat(prefix, elements), suffix);
      return makeArray(all).subArray(2, elements.length + 2).asList();
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  @AndroidIncompatible
  private static Double[] concat(Double[] a, Double[] b) {
    return ObjectArrays.concat(a, b, Double.class);
  }

   */
  abstract double singleQuantile(int index, int scale, double[] dataset);

  /**
   * Calculates multiple quantiles. Equivalent to {@code
   * Quantiles.scale(scale).indexes(indexes).computeInPlace(dataset)}.
   */
  abstract Map<Integer, Double> multipleQuantiles(
      Collection<Integer> indexes, int scale, double[] dataset);

  static double getMinValue(double[] array, int from) {

  }

  static final ImmutableSet<Double> INTEGRAL_DOUBLE_CANDIDATES;
  static final ImmutableSet<Double> FRACTIONAL_DOUBLE_CANDIDATES;
  static final Iterable<Double> INFINITIES =
      Doubles.asList(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
  static final Iterable<Double> FINITE_DOUBLE_CANDIDATES;
  static final Iterable<Double> POSITIVE_FINITE_DOUBLE_CANDIDATES;