Class SecondMoment

    • Field Detail

      • m2

        protected double m2
        Second moment of values that have been added
      • n

        protected long n
        Count of values that have been added
      • m1

        protected double m1
        First moment of values that have been added
      • dev

        protected double dev
        Deviation of most recently added value from previous first moment. Retained to prevent repeated computation in higher order moments.
      • nDev

        protected double nDev
        Deviation of most recently added value from previous first moment, normalized by previous sample size. Retained to prevent repeated computation in higher order moments.
    • Constructor Detail

      • SecondMoment

        public SecondMoment()
        Create a SecondMoment instance.
      • SecondMoment

        public SecondMoment​(SecondMoment original)
                     throws NullArgumentException
        Copy constructor, creates a new SecondMoment identical to the original.
        Parameters:
        original - the SecondMoment instance to copy
        Throws:
        NullArgumentException - if original is null
    • Method Detail

      • increment

        public void increment​(double d)
        Updates the internal state of the statistic to reflect the addition of the new value.
        Specified by:
        increment in interface StorelessUnivariateStatistic
        Parameters:
        d - the new value.
      • getResult

        public double getResult()
        Returns the current value of the Statistic.
        Specified by:
        getResult in interface StorelessUnivariateStatistic
        Returns:
        value of the statistic, Double.NaN if it has been cleared or just instantiated.
      • aggregate

        public void aggregate​(SecondMoment other)
        Aggregates the provided instance into this instance.

        This method can be used to combine statistics computed over partitions or subsamples - i.e., the value of this instance after this operation should be the same as if a single statistic would have been applied over the combined dataset.

        Specified by:
        aggregate in interface AggregatableStatistic<SecondMoment>
        Parameters:
        other - the instance to aggregate into this instance
      • getN

        public long getN()
        Returns the number of values that have been added.
        Specified by:
        getN in interface StorelessUnivariateStatistic
        Returns:
        the number of values.
      • aggregate

        protected void aggregate​(org.hipparchus.stat.descriptive.moment.FirstMoment other)
        Aggregates the results of the provided instance into this instance.
        Parameters:
        other - the instance to aggregate from