Package org.apache.commons.statistics.descriptive

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:

• Sum
• Math.log(double)

Method Summary

Modifier and Type	Method	Description
void	accept(double value)	Updates the state of the statistic to reflect the addition of value.
SumOfLogs	combine(SumOfLogs other)	Combines the state of the other statistic into this one.
static SumOfLogs	create()	Creates an instance.
double	getAsDouble()	Gets the sum of all input values.
static SumOfLogs	of(double... values)	Returns an instance populated using the input values.
static SumOfLogs	of(int... values)	Returns an instance populated using the input values.
static SumOfLogs	of(long... values)	Returns an instance populated using the input values.
static SumOfLogs	ofRange(double[] values, int from, int to)	Returns an instance populated using the specified range of values.
static SumOfLogs	ofRange(int[] values, int from, int to)	Returns an instance populated using the specified range of values.
static SumOfLogs	ofRange(long[] values, int from, int to)	Returns an instance populated using the specified range of values.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.function.DoubleConsumer

andThen

Methods inherited from interface org.apache.commons.statistics.descriptive.StatisticResult

getAsBigInteger, getAsInt, getAsLong

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.

ofRange

public static SumOfLogs ofRange(double[] values,
 int from,
 int to)

Returns an instance populated using the specified range of 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 range is empty, the result is zero.

Parameters:

values - Values.

from - Inclusive start of the range.

to - Exclusive end of the range.

Returns:

SumOfLogs instance.

Throws:

IndexOutOfBoundsException - if the sub-range is out of bounds

Since:

1.2

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.

ofRange

public static SumOfLogs ofRange(int[] values,
 int from,
 int to)

Returns an instance populated using the specified range of values.

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

When the range is empty, the result is zero.

Parameters:

values - Values.

from - Inclusive start of the range.

to - Exclusive end of the range.

Returns:

SumOfLogs instance.

Throws:

IndexOutOfBoundsException - if the sub-range is out of bounds

Since:

1.2

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.

ofRange

public static SumOfLogs ofRange(long[] values,
 int from,
 int to)

Returns an instance populated using the specified range of values.

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

When the range is empty, the result is zero.

Parameters:

values - Values.

from - Inclusive start of the range.

to - Exclusive end of the range.

Returns:

SumOfLogs instance.

Throws:

IndexOutOfBoundsException - if the sub-range is out of bounds

Since:

1.2

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.