* value).hashCode()}.
   *
   * <p><b>Java 8+ users:</b> use {@link Double#hashCode(double)} instead.
   *
   * @param value a primitive {@code double} value
   * @return a hash code for the value
   */
  public static int hashCode(double value) {
    return ((Double) value).hashCode();
    // TODO(kevinb): do it this way when we can (GWT problem):
    // long bits = Double.doubleToLongBits(value);

      return LinearTransformation.vertical(xStats.mean());
    }
  }

  private double ensurePositive(double value) {
    if (value > 0.0) {
      return value;
    } else {
      return Double.MIN_VALUE;
    }
  }

  private static double ensureInUnitRange(double value) {
    return Doubles.constrainToRange(value, -1.0, 1.0);
  }

  public static int roundToInt(double x, RoundingMode mode) {
    double z = roundIntermediate(x, mode);
    checkInRangeForRoundingInputs(
        z > MIN_INT_AS_DOUBLE - 1.0 & z < MAX_INT_AS_DOUBLE + 1.0, x, mode);
    return (int) z;
  }

  private static final double MIN_INT_AS_DOUBLE = -0x1p31;
  private static final double MAX_INT_AS_DOUBLE = 0x1p31 - 1.0;

  /**

      Double[] suffix = {(double) 86, (double) 99};
      Double[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Double[] concat(Double[] left, Double[] right) {
    Double[] result = new Double[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

  }

  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;

      Double[] suffix = {(double) 86, (double) 99};
      Double[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Double[] concat(Double[] left, Double[] right) {
    Double[] result = new Double[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

    KAHAN {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        double c = 0.0;
        for (double value : values) {
          double y = value - c;
          double t = sum + y;
          c = (t - sum) - y;
          sum = t;
        }
        return sum / values.length;
      }
    },
    KNUTH {
      @Override
      double mean(double[] values) {
        double mean = values[0];

    KAHAN {
      @Override
      double mean(double[] values) {
        double sum = 0.0;
        double c = 0.0;
        for (double value : values) {
          double y = value - c;
          double t = sum + y;
          c = (t - sum) - y;
          sum = t;
        }
        return sum / values.length;
      }
    },
    KNUTH {
      @Override
      double mean(double[] values) {
        double mean = values[0];

    BigDecimal maxDoubleAsBD = new BigDecimal(Double.MAX_VALUE);
    new RoundToDoubleTester(maxDoubleAsBD).setExpectation(Double.MAX_VALUE, values()).test();
  }

  public void testRoundToDouble_maxDoublePlusOne() {
    BigDecimal maxDoubleAsBD = new BigDecimal(Double.MAX_VALUE).add(BigDecimal.ONE);
    new RoundToDoubleTester(maxDoubleAsBD)
        .setExpectation(Double.MAX_VALUE, DOWN, FLOOR, HALF_EVEN, HALF_UP, HALF_DOWN)

  }

  public void testLog2NaNInfinity() {
    assertEquals(Double.POSITIVE_INFINITY, DoubleMath.log2(Double.POSITIVE_INFINITY));
    assertTrue(Double.isNaN(DoubleMath.log2(Double.NEGATIVE_INFINITY)));
    assertTrue(Double.isNaN(DoubleMath.log2(Double.NaN)));
  }

  @GwtIncompatible // StrictMath
  private strictfp double trueLog2(double d) {