class TimeSeriesWeightedVolatilityOperator extends Function1D<DateDoubleTimeSeries<?>, DateDoubleTimeSeries<?>> {

  public static TimeSeriesWeightedVolatilityOperator relative(double lambda) {
    return new TimeSeriesWeightedVolatilityOperator(RELATIVE_CHANGE, lambda, DEFAULT_SEED_LENGTH);
  }

  public  TimeSeriesWeightedVolatilityOperator(
      Function1D<DateDoubleTimeSeries<?>, DateDoubleTimeSeries<?>> returnOperator, 
      double lambda,
      int seedLength);

}