## Class SummaryStatistics

- java.lang.Object
- org.apache.commons.math3.stat.descriptive.SummaryStatistics

- All Implemented Interfaces:
- Serializable, StatisticalSummary

- Direct Known Subclasses:
- SynchronizedSummaryStatistics

public class SummaryStatisticsextends Objectimplements StatisticalSummary, Serializable

Computes summary statistics for a stream of data values added using the

`addValue`

method. The data values are not stored in memory, so this class can be used to compute statistics for very large data streams.The

`StorelessUnivariateStatistic`

instances used to maintain summary state and compute statistics are configurable via setters. For example, the default implementation for the variance can be overridden by calling`setVarianceImpl(StorelessUnivariateStatistic)`

. Actual parameters to these methods must implement the`StorelessUnivariateStatistic`

interface and configuration must be completed before`addValue`

is called. No configuration is necessary to use the default, commons-math provided implementations.Note: This class is not thread-safe. Use

`SynchronizedSummaryStatistics`

if concurrent access from multiple threads is required.- See Also:
- Serialized Form

### Constructor Summary

Constructors Constructor and Description **SummaryStatistics**()Construct a SummaryStatistics instance**SummaryStatistics**(SummaryStatistics original)A copy constructor.

### Method Summary

Methods Modifier and Type Method and Description `void`

**addValue**(double value)Add a value to the data`void`

**clear**()Resets all statistics and storage`SummaryStatistics`

**copy**()Returns a copy of this SummaryStatistics instance with the same internal state.`static void`

**copy**(SummaryStatistics source, SummaryStatistics dest)Copies source to dest.`boolean`

**equals**(Object object)Returns true iff`object`

is a`SummaryStatistics`

instance and all statistics have the same values as this.`StorelessUnivariateStatistic`

**getGeoMeanImpl**()Returns the currently configured geometric mean implementation`double`

**getGeometricMean**()Returns the geometric mean of the values that have been added.`double`

**getMax**()Returns the maximum of the values that have been added.`StorelessUnivariateStatistic`

**getMaxImpl**()Returns the currently configured maximum implementation`double`

**getMean**()Returns the mean of the values that have been added.`StorelessUnivariateStatistic`

**getMeanImpl**()Returns the currently configured mean implementation`double`

**getMin**()Returns the minimum of the values that have been added.`StorelessUnivariateStatistic`

**getMinImpl**()Returns the currently configured minimum implementation`long`

**getN**()Returns the number of available values`double`

**getPopulationVariance**()Returns the population variance of the values that have been added.`double`

**getSecondMoment**()Returns a statistic related to the Second Central Moment.`double`

**getStandardDeviation**()Returns the standard deviation of the values that have been added.`double`

**getSum**()Returns the sum of the values that have been added`StorelessUnivariateStatistic`

**getSumImpl**()Returns the currently configured Sum implementation`StorelessUnivariateStatistic`

**getSumLogImpl**()Returns the currently configured sum of logs implementation`StatisticalSummary`

**getSummary**()Return a`StatisticalSummaryValues`

instance reporting current statistics.`double`

**getSumOfLogs**()Returns the sum of the logs of the values that have been added.`double`

**getSumsq**()Returns the sum of the squares of the values that have been added.`StorelessUnivariateStatistic`

**getSumsqImpl**()Returns the currently configured sum of squares implementation`double`

**getVariance**()Returns the (sample) variance of the available values.`StorelessUnivariateStatistic`

**getVarianceImpl**()Returns the currently configured variance implementation`int`

**hashCode**()Returns hash code based on values of statistics`void`

**setGeoMeanImpl**(StorelessUnivariateStatistic geoMeanImpl)Sets the implementation for the geometric mean.`void`

**setMaxImpl**(StorelessUnivariateStatistic maxImpl)Sets the implementation for the maximum.`void`

**setMeanImpl**(StorelessUnivariateStatistic meanImpl)Sets the implementation for the mean.`void`

**setMinImpl**(StorelessUnivariateStatistic minImpl)Sets the implementation for the minimum.`void`

**setSumImpl**(StorelessUnivariateStatistic sumImpl)Sets the implementation for the Sum.`void`

**setSumLogImpl**(StorelessUnivariateStatistic sumLogImpl)Sets the implementation for the sum of logs.`void`

**setSumsqImpl**(StorelessUnivariateStatistic sumsqImpl)Sets the implementation for the sum of squares.`void`

**setVarianceImpl**(StorelessUnivariateStatistic varianceImpl)Sets the implementation for the variance.`String`

**toString**()Generates a text report displaying summary statistics from values that have been added.

### Constructor Detail

#### SummaryStatistics

public SummaryStatistics()

Construct a SummaryStatistics instance

#### SummaryStatistics

public SummaryStatistics(SummaryStatistics original) throws NullArgumentException

A copy constructor. Creates a deep-copy of the`original`

.- Parameters:
`original`

- the`SummaryStatistics`

instance to copy- Throws:
`NullArgumentException`

- if original is null

### Method Detail

#### getSummary

public StatisticalSummary getSummary()

Return a`StatisticalSummaryValues`

instance reporting current statistics.- Returns:
- Current values of statistics

#### addValue

public void addValue(double value)

Add a value to the data- Parameters:
`value`

- the value to add

#### getN

public long getN()

Returns the number of available values**Specified by:**`getN`

in interface`StatisticalSummary`

- Returns:
- The number of available values

#### getSum

public double getSum()

Returns the sum of the values that have been added**Specified by:**`getSum`

in interface`StatisticalSummary`

- Returns:
- The sum or
`Double.NaN`

if no values have been added

#### getSumsq

public double getSumsq()

Returns the sum of the squares of the values that have been added.Double.NaN is returned if no values have been added.

- Returns:
- The sum of squares

#### getMean

public double getMean()

Returns the mean of the values that have been added.Double.NaN is returned if no values have been added.

**Specified by:**`getMean`

in interface`StatisticalSummary`

- Returns:
- the mean

#### getStandardDeviation

public double getStandardDeviation()

Returns the standard deviation of the values that have been added.Double.NaN is returned if no values have been added.

**Specified by:**`getStandardDeviation`

in interface`StatisticalSummary`

- Returns:
- the standard deviation

#### getVariance

public double getVariance()

Returns the (sample) variance of the available values.This method returns the bias-corrected sample variance (using

`n - 1`

in the denominator). Use`getPopulationVariance()`

for the non-bias-corrected population variance.Double.NaN is returned if no values have been added.

**Specified by:**`getVariance`

in interface`StatisticalSummary`

- Returns:
- the variance

#### getPopulationVariance

public double getPopulationVariance()

Returns the population variance of the values that have been added.Double.NaN is returned if no values have been added.

- Returns:
- the population variance

#### getMax

public double getMax()

Returns the maximum of the values that have been added.Double.NaN is returned if no values have been added.

**Specified by:**`getMax`

in interface`StatisticalSummary`

- Returns:
- the maximum

#### getMin

public double getMin()

Returns the minimum of the values that have been added.Double.NaN is returned if no values have been added.

**Specified by:**`getMin`

in interface`StatisticalSummary`

- Returns:
- the minimum

#### getGeometricMean

public double getGeometricMean()

Returns the geometric mean of the values that have been added.Double.NaN is returned if no values have been added.

- Returns:
- the geometric mean

#### getSumOfLogs

public double getSumOfLogs()

Returns the sum of the logs of the values that have been added.Double.NaN is returned if no values have been added.

- Returns:
- the sum of logs

#### getSecondMoment

public double getSecondMoment()

Returns a statistic related to the Second Central Moment. Specifically, what is returned is the sum of squared deviations from the sample mean among the values that have been added.Returns

`Double.NaN`

if no data values have been added and returns`0`

if there is just one value in the data set.- Returns:
- second central moment statistic

#### toString

public String toString()

Generates a text report displaying summary statistics from values that have been added.

#### clear

public void clear()

Resets all statistics and storage

#### equals

public boolean equals(Object object)

Returns true iff`object`

is a`SummaryStatistics`

instance and all statistics have the same values as this.

#### hashCode

public int hashCode()

Returns hash code based on values of statistics

#### getSumImpl

public StorelessUnivariateStatistic getSumImpl()

Returns the currently configured Sum implementation- Returns:
- the StorelessUnivariateStatistic implementing the sum

#### setSumImpl

public void setSumImpl(StorelessUnivariateStatistic sumImpl) throws MathIllegalStateException

Sets the implementation for the Sum.

This method cannot be activated after data has been added - i.e., after

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`sumImpl`

- the StorelessUnivariateStatistic instance to use for computing the Sum- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n >0)

#### getSumsqImpl

public StorelessUnivariateStatistic getSumsqImpl()

Returns the currently configured sum of squares implementation- Returns:
- the StorelessUnivariateStatistic implementing the sum of squares

#### setSumsqImpl

public void setSumsqImpl(StorelessUnivariateStatistic sumsqImpl) throws MathIllegalStateException

Sets the implementation for the sum of squares.

This method cannot be activated after data has been added - i.e., after

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`sumsqImpl`

- the StorelessUnivariateStatistic instance to use for computing the sum of squares- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getMinImpl

public StorelessUnivariateStatistic getMinImpl()

Returns the currently configured minimum implementation- Returns:
- the StorelessUnivariateStatistic implementing the minimum

#### setMinImpl

public void setMinImpl(StorelessUnivariateStatistic minImpl) throws MathIllegalStateException

Sets the implementation for the minimum.

This method cannot be activated after data has been added - i.e., after

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`minImpl`

- the StorelessUnivariateStatistic instance to use for computing the minimum- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getMaxImpl

public StorelessUnivariateStatistic getMaxImpl()

Returns the currently configured maximum implementation- Returns:
- the StorelessUnivariateStatistic implementing the maximum

#### setMaxImpl

public void setMaxImpl(StorelessUnivariateStatistic maxImpl) throws MathIllegalStateException

Sets the implementation for the maximum.

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`maxImpl`

- the StorelessUnivariateStatistic instance to use for computing the maximum- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getSumLogImpl

public StorelessUnivariateStatistic getSumLogImpl()

Returns the currently configured sum of logs implementation- Returns:
- the StorelessUnivariateStatistic implementing the log sum

#### setSumLogImpl

public void setSumLogImpl(StorelessUnivariateStatistic sumLogImpl) throws MathIllegalStateException

Sets the implementation for the sum of logs.

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`sumLogImpl`

- the StorelessUnivariateStatistic instance to use for computing the log sum- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getGeoMeanImpl

public StorelessUnivariateStatistic getGeoMeanImpl()

Returns the currently configured geometric mean implementation- Returns:
- the StorelessUnivariateStatistic implementing the geometric mean

#### setGeoMeanImpl

public void setGeoMeanImpl(StorelessUnivariateStatistic geoMeanImpl) throws MathIllegalStateException

Sets the implementation for the geometric mean.

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`geoMeanImpl`

- the StorelessUnivariateStatistic instance to use for computing the geometric mean- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getMeanImpl

public StorelessUnivariateStatistic getMeanImpl()

Returns the currently configured mean implementation- Returns:
- the StorelessUnivariateStatistic implementing the mean

#### setMeanImpl

public void setMeanImpl(StorelessUnivariateStatistic meanImpl) throws MathIllegalStateException

Sets the implementation for the mean.

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`meanImpl`

- the StorelessUnivariateStatistic instance to use for computing the mean- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### getVarianceImpl

public StorelessUnivariateStatistic getVarianceImpl()

Returns the currently configured variance implementation- Returns:
- the StorelessUnivariateStatistic implementing the variance

#### setVarianceImpl

public void setVarianceImpl(StorelessUnivariateStatistic varianceImpl) throws MathIllegalStateException

Sets the implementation for the variance.

`addValue`

has been used to add data. If it is activated after data has been added, an IllegalStateException will be thrown.- Parameters:
`varianceImpl`

- the StorelessUnivariateStatistic instance to use for computing the variance- Throws:
`MathIllegalStateException`

- if data has already been added (i.e if n > 0)

#### copy

public SummaryStatistics copy()

Returns a copy of this SummaryStatistics instance with the same internal state.- Returns:
- a copy of this

#### copy

public static void copy(SummaryStatistics source, SummaryStatistics dest) throws NullArgumentException

Copies source to dest.Neither source nor dest can be null.

- Parameters:
`source`

- SummaryStatistics to copy`dest`

- SummaryStatistics to copy to- Throws:
`NullArgumentException`

- if either source or dest is null

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