assertBitEquals(x + y, a.get());
      }
    }
  }

  /** getAndAccumulate with sum adds given value to current, and returns previous value */
  public void testGetAndAccumulateWithSum() {
    for (double x : VALUES) {
      for (double y : VALUES) {
        AtomicDouble a = new AtomicDouble(x);
        double z = a.getAndAccumulate(y, Double::sum);
        assertBitEquals(x, z);
        assertBitEquals(x + y, a.get());

      }
    }
  }

  /** getAndAccumulate with sum adds given value to current, and returns previous value */
  public void testGetAndAccumulateWithSum() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      for (double x : VALUES) {
        for (double y : VALUES) {
          aa.set(i, x);
          double z = aa.getAndAccumulate(i, y, Double::sum);

   *
   * @param i the index
   * @param delta the value to add
   * @return the previous value
   */
  @CanIgnoreReturnValue
  public final double getAndAdd(int i, double delta) {
    return getAndAccumulate(i, delta, Double::sum);
  }

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

  /**
   * Adds {@code delta} to the value currently associated with {@code key}, and returns the old
   * value.
   */
  @CanIgnoreReturnValue
  public long getAndAdd(K key, long delta) {
    return getAndAccumulate(key, delta, Long::sum);
  }

  /**
   * Updates the value currently associated with {@code key} with the specified function, and