code: public final boolean compareAndSet(int i, double expect, double update) {
      return longs.compareAndSet(i, doubleToRawLongBits(expect), doubleToRawLongBits(update));
    }
docs: Atomically sets the element at position {@code i} to the given updated value if the current
  value is <a href="#bitEquals">bitwise equal</a> to the expected value.
  
  @param i the index
  @param expect the expected value
  @param update the new value
  @return true if successful. False return indicates that the actual value was not equal to the
  expected value.