* probability.
   */
  static BigInteger randomNonZeroBigInteger(int numBits) {
    BigInteger result = randomPositiveBigInteger(numBits);
    return RANDOM_SOURCE.nextBoolean() ? result : result.negate();
  }

  /**
   * Chooses a number in (-2^numBits, 2^numBits) at random, with density concentrated in numbers of
   * lower magnitude.
   */
  static BigInteger randomBigInteger(int numBits) {

        .setExpectation(Double.NEGATIVE_INFINITY, UP, FLOOR)
        .roundUnnecessaryShouldThrow()
        .test();
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testRoundToDouble_negativeWayTooBig() {
    BigInteger bi = BigInteger.ONE.shiftLeft(2 * Double.MAX_EXPONENT).negate();
    new RoundToDoubleTester(bi)

        .setExpectation(Double.NEGATIVE_INFINITY, UP, FLOOR)
        .roundUnnecessaryShouldThrow()
        .test();
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testRoundToDouble_negativeWayTooBig() {
    BigInteger bi = BigInteger.ONE.shiftLeft(2 * Double.MAX_EXPONENT).negate();
    new RoundToDoubleTester(bi)

    MathPreconditions.checkPositive("BigInteger", BigInteger.ONE);
  }

  public void testCheckPositive_negativeBigInteger() {
    try {
      MathPreconditions.checkPositive("BigInteger", BigInteger.ZERO.negate());
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCheckNonNegative_zeroInt() {
    MathPreconditions.checkNonNegative("int", 0);
  }

   * @throws IllegalArgumentException if {@code permitsPerSecond} is negative or zero or {@code
   *     warmupPeriod} is negative
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public static RateLimiter create(double permitsPerSecond, long warmupPeriod, TimeUnit unit) {
    checkArgument(warmupPeriod >= 0, "warmupPeriod must not be negative: %s", warmupPeriod);
    return create(

    if (lower == NEGATIVE_INFINITY) {
      if (upper == POSITIVE_INFINITY) {
        // Return NaN when lower == NEGATIVE_INFINITY and upper == POSITIVE_INFINITY:
        return NaN;
      }
      // Return NEGATIVE_INFINITY when NEGATIVE_INFINITY == lower <= upper < POSITIVE_INFINITY:
      return NEGATIVE_INFINITY;
    }
    if (upper == POSITIVE_INFINITY) {

    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, Double.NEGATIVE_INFINITY));
  }

  public void testMappingAnd_infiniteX2() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, 3.4).and(Double.NEGATIVE_INFINITY, 7.8));
  }

  public void testMappingAnd_infiniteY2() {
    assertThrows(

    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, Double.NEGATIVE_INFINITY));
  }

  public void testMappingAnd_infiniteX2() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, 3.4).and(Double.NEGATIVE_INFINITY, 7.8));
  }

  public void testMappingAnd_infiniteY2() {
    assertThrows(

 *   if (value < 0) {
 *     throw new IllegalArgumentException("input is negative: " + value);
 *   }
 *   // calculate square root
 * }
 * }</pre>
 *
 * <p>to be replaced with the more compact
 *
 * <pre>{@code
 * public static double sqrt(double value) {
 *   checkArgument(value >= 0, "input is negative: %s", value);
 *   // calculate square root
 * }
 * }</pre>
 *

public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);