}

  /** repeated weakCompareAndSet succeeds in changing value when equal to expected */
  public void testWeakCompareAndSet() {
    double prev = Math.E;
    double unused = Math.E + Math.PI;
    AtomicDouble at = new AtomicDouble(prev);
    for (double x : VALUES) {
      assertBitEquals(prev, at.get());
      assertFalse(at.weakCompareAndSet(unused, x));
      assertBitEquals(prev, at.get());

   *
   * @param expect the expected value
   * @param update the new value
   * @return {@code true} if successful
   */
  public final boolean weakCompareAndSet(double expect, double update) {
    return value.weakCompareAndSet(doubleToRawLongBits(expect), doubleToRawLongBits(update));
  }

  /**
   * Atomically adds the given value to the current value.
   *
   * @param delta the value to add

   *
   * @param i the index
   * @param expect the expected value
   * @param update the new value
   * @return true if successful
   */
  public final boolean weakCompareAndSet(int i, double expect, double update) {
    return longs.weakCompareAndSet(i, doubleToRawLongBits(expect), doubleToRawLongBits(update));
  }

  /**
   * Atomically adds the given value to the element at index {@code i}.
   *