Class Product

    • Constructor Detail

      • Product

        public Product()
        Create a Product instance.
      • Product

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

      • 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

        public void aggregate​(Product 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<Product>
        Parameters:
        other - the instance to aggregate into this instance
      • evaluate

        public double evaluate​(double[] values,
                               double[] weights,
                               int begin,
                               int length)
                        throws MathIllegalArgumentException
        Returns the weighted product of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.

        Throws MathIllegalArgumentException if any of the following are true:

        • the values array is null
        • the weights array is null
        • the weights array does not have the same length as the values array
        • the weights array contains one or more infinite values
        • the weights array contains one or more NaN values
        • the weights array contains negative values
        • the start and length arguments do not determine a valid array

        Uses the formula \(\mathrm{weighted product} = \prod \mathrm{values}_i^{\mathrm{weights}_i}\)

        that is, the weights are applied as exponents when computing the weighted product.

        Specified by:
        evaluate in interface WeightedEvaluation
        Parameters:
        values - the input array
        weights - the weights array
        begin - index of the first array element to include
        length - the number of elements to include
        Returns:
        the product of the values or 1 if length = 0
        Throws:
        MathIllegalArgumentException - if the parameters are not valid