assertEquals(Double.NEGATIVE_INFINITY, DoubleMath.log2(-0.0));
  }

  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

          return Double.MAX_VALUE * sign(x);
        case FLOOR:
          return (roundArbitrarily == Double.POSITIVE_INFINITY)
              ? Double.MAX_VALUE
              : Double.NEGATIVE_INFINITY;
        case CEILING:
          return (roundArbitrarily == Double.POSITIVE_INFINITY)
              ? Double.POSITIVE_INFINITY
              : -Double.MAX_VALUE;
        case UP:
          return roundArbitrarily;
        case UNNECESSARY:

        .containsExactly(
            0, NEGATIVE_INFINITY,
            1, NaN, // interpolating between NEGATIVE_ and POSITIVE_INFINITY values
            2, POSITIVE_INFINITY,
            8, POSITIVE_INFINITY,
            9, POSITIVE_INFINITY, // interpolating between two POSITIVE_INFINITY values
            10, POSITIVE_INFINITY);
  }

  public void testScale_indexes_varargs_compute_doubleCollection_nan() {

        .containsExactly(
            0, NEGATIVE_INFINITY,
            1, NaN, // interpolating between NEGATIVE_ and POSITIVE_INFINITY values
            2, POSITIVE_INFINITY,
            8, POSITIVE_INFINITY,
            9, POSITIVE_INFINITY, // interpolating between two POSITIVE_INFINITY values
            10, POSITIVE_INFINITY);
  }

  public void testScale_indexes_varargs_compute_doubleCollection_nan() {

   * 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}.
   * If it contains {@link Double#NEGATIVE_INFINITY} and finite values only or {@link

   * 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}.
   * If it contains {@link Double#NEGATIVE_INFINITY} and finite values only or {@link

      assertEquals(positiveValue, DoubleUtils.ensureNonNegative(positiveValue));
      assertEquals(0.0, DoubleUtils.ensureNonNegative(-positiveValue));
    }
    assertEquals(Double.POSITIVE_INFINITY, DoubleUtils.ensureNonNegative(Double.POSITIVE_INFINITY));
    assertEquals(0.0, DoubleUtils.ensureNonNegative(Double.NEGATIVE_INFINITY));
    assertThrows(IllegalArgumentException.class, () -> DoubleUtils.ensureNonNegative(Double.NaN));
  }

    assertEquals(Double.NEGATIVE_INFINITY, DoubleMath.log2(-0.0));
  }

  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

   * times, due to numerical errors.
   *
   * <h3>Non-finite values</h3>
   *
   * <p>If the dataset contains any non-finite values ({@link Double#POSITIVE_INFINITY}, {@link
   * Double#NEGATIVE_INFINITY}, or {@link Double#NaN}) then the result is {@link Double#NaN}.
   *
   * @throws IllegalStateException if the dataset is empty
   */
  public double populationCovariance() {

      assertEquals(positiveValue, DoubleUtils.ensureNonNegative(positiveValue));
      assertEquals(0.0, DoubleUtils.ensureNonNegative(-positiveValue));
    }
    assertEquals(Double.POSITIVE_INFINITY, DoubleUtils.ensureNonNegative(Double.POSITIVE_INFINITY));
    assertEquals(0.0, DoubleUtils.ensureNonNegative(Double.NEGATIVE_INFINITY));
    assertThrows(IllegalArgumentException.class, () -> DoubleUtils.ensureNonNegative(Double.NaN));
  }