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
   */

  static final double MANY_VALUES_MAX = 555.555;
  static final double MANY_VALUES_MIN = -44.44;

  // Doubles which will overflow if summed:
  static final double[] LARGE_VALUES = {Double.MAX_VALUE, Double.MAX_VALUE / 2.0};
  static final double LARGE_VALUES_MEAN = 0.75 * Double.MAX_VALUE;

  static final ImmutableList<Double> OTHER_MANY_VALUES =

  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,

   */
  public static boolean fuzzyEquals(double a, double b, double tolerance) {
    MathPreconditions.checkNonNegative("tolerance", tolerance);
    return Math.copySign(a - b, 1.0) <= tolerance
        // copySign(x, 1.0) is a branch-free version of abs(x), but with different NaN semantics
        || (a == b) // needed to ensure that infinities equal themselves
        || (Double.isNaN(a) && Double.isNaN(b));
  }

  /**

   *
   * <p>If the dataset contains {@link Double#NaN} then the result is {@link Double#NaN}. If it
   * contains both {@link Double#POSITIVE_INFINITY} and {@link Double#NEGATIVE_INFINITY} then the
   * result is {@link Double#NaN}. If it contains {@link Double#POSITIVE_INFINITY} and finite values
   * only or {@link Double#POSITIVE_INFINITY} only, the result is {@link Double#POSITIVE_INFINITY}.

 * from {@link Double#equals}, as if implemented by:
 *
 * {@snippet :
 * static boolean bitEquals(double x, double y) {
 *   long xBits = Double.doubleToRawLongBits(x);
 *   long yBits = Double.doubleToRawLongBits(y);
 *   return xBits == yBits;
 * }
 * }
 *
 * <p>It is possible to write a more scalable updater, at the cost of giving up strict atomicity.
 * See for example <a

  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,

 * Double#doubleToRawLongBits}, which differs from both the primitive double {@code ==} operator and
 * from {@link Double#equals}, as if implemented by:
 *
 * {@snippet :
 * static boolean bitEquals(double x, double y) {
 *   long xBits = Double.doubleToRawLongBits(x);
 *   long yBits = Double.doubleToRawLongBits(y);
 *   return xBits == yBits;
 * }
 * }
 *
 * @author Doug Lea
 * @author Martin Buchholz
 * @since 11.0
 */

    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;