Package org.apache.commons.statistics.descriptive

Class SumOfLogs

  • All Implemented Interfaces:
    DoubleConsumer, DoubleSupplier, IntSupplier, LongSupplier, DoubleStatistic, StatisticAccumulator<SumOfLogs>, StatisticResult
    public final class SumOfLogs
extends Object
implements DoubleStatistic, StatisticAccumulator<SumOfLogs>
    Returns the sum of the natural logarithm of available values.
    • The result is zero if no values are added.
    • The result is NaN if any of the values is NaN.
    • The result is NaN if any of the values is negative.

    The sum follows the IEEE754 result for summing infinite values:

    • The result is +infinity if all values are in the range (0, +infinity] and at least one value is +infinity.
    • The result is -infinity if all values are in the range [0, +infinity) and at least one value is zero.
    • The result is NaN if all values are in the range [0, +infinity] and at least one value is zero, and one value is +infinity.

    This class is designed to work with (though does not require) streams.

    This instance is not thread safe. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the accept or combine method, it must be synchronized externally.

    However, it is safe to use accept and combine as accumulator and combiner functions of Collector on a parallel stream, because the parallel instance of Stream.collect() provides the necessary partitioning, isolation, and merging of results for safe and efficient parallel execution.

    Since:
    1.1
    See Also:
    Sum, Math.log(double)

    • Method Detail

      • create

        public static SumOfLogs create()
        Creates an instance.

        The initial result is zero.

        Returns:
        SumOfLogs instance.

      • of

        public static SumOfLogs of​(double... values)
        Returns an instance populated using the input values.

        The result is NaN if any of the values is NaN or negative; or the sum at any point is a NaN.

        When the input is an empty array, the result is zero.

        Parameters:
        values - Values.
        Returns:
        SumOfLogs instance.

      • of

        public static SumOfLogs of​(int... values)
        Returns an instance populated using the input values.

        The result is NaN if any of the values is negative.

        When the input is an empty array, the result is zero.

        Parameters:
        values - Values.
        Returns:
        SumOfLogs instance.

      • of

        public static SumOfLogs of​(long... values)
        Returns an instance populated using the input values.

        The result is NaN if any of the values is negative.

        When the input is an empty array, the result is zero.

        Parameters:
        values - Values.
        Returns:
        SumOfLogs instance.

      • accept

        public void accept​(double value)
        Updates the state of the statistic to reflect the addition of value.
        Specified by:
        accept in interface DoubleConsumer
        Parameters:
        value - Value.

      • getAsDouble

        public double getAsDouble()
        Gets the sum of all input values.

        When no values have been added, the result is zero.

        Specified by:
        getAsDouble in interface DoubleSupplier
        Returns:
        sum of all values.