Class SumOfLogs

java.lang.Object
org.apache.commons.statistics.descriptive.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:

  • Field Details

    • delegate

      private final org.apache.commons.numbers.core.Sum delegate
      Sum used to compute the sum.

  • Constructor Details

    • SumOfLogs

      private SumOfLogs()
      Create an instance.

  • Method Details

    • 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.

    • combine

      public SumOfLogs combine(SumOfLogs other)
      Description copied from interface: StatisticAccumulator
      Combines the state of the other statistic into this one.
      Specified by:
      combine in interface StatisticAccumulator<SumOfLogs>
      Parameters:
      other - Another statistic to be combined.
      Returns:
      this instance after combining other.