Package org.apache.commons.math.stat.descriptive

Class SummaryStatistics

  • All Implemented Interfaces:
    java.io.Serializable, StatisticalSummary
    Direct Known Subclasses:
    SynchronizedSummaryStatistics
    public class SummaryStatistics
extends java.lang.Object
implements StatisticalSummary, java.io.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.

    Version:
    $Revision: 1042376 $ $Date: 2010-12-05 16:54:55 +0100 (dim. 05 déc. 2010) $
    See Also:
    Serialized Form

    • Field Detail

      • n

        protected long n
        count of values that have been added

      • secondMoment

        protected SecondMoment secondMoment
        SecondMoment is used to compute the mean and variance

      • sum

        protected Sum sum
        sum of values that have been added

      • sumsq

        protected SumOfSquares sumsq
        sum of the square of each value that has been added

      • min

        protected Min min
        min of values that have been added

      • max

        protected Max max
        max of values that have been added

      • sumLog

        protected SumOfLogs sumLog
        sumLog of values that have been added

      • geoMean

        protected GeometricMean geoMean
        geoMean of values that have been added

      • mean

        protected Mean mean
        mean of values that have been added

      • variance

        protected Variance variance
        variance of values that have been added

    • Constructor Detail

      • SummaryStatistics

        public SummaryStatistics()
        Construct a SummaryStatistics instance

      • SummaryStatistics

        public SummaryStatistics​(SummaryStatistics original)
        A copy constructor. Creates a deep-copy of the original.
        Parameters:
        original - the SummaryStatistics instance to copy

    • Method Detail

      • 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 variance of the values that have been added.

        Double.NaN is returned if no values have been added.

        Specified by:
        getVariance in interface StatisticalSummary
        Returns:
        the 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
        Since:
        1.2

      • 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
        Since:
        2.0

      • toString

        public java.lang.String toString()
        Generates a text report displaying summary statistics from values that have been added.
        Overrides:
        toString in class java.lang.Object
        Returns:
        String with line feeds displaying statistics
        Since:
        1.2

      • clear

        public void clear()
        Resets all statistics and storage

      • equals

        public boolean equals​(java.lang.Object object)
        Returns true iff object is a SummaryStatistics instance and all statistics have the same values as this.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        object - the object to test equality against.
        Returns:
        true if object equals this

      • hashCode

        public int hashCode()
        Returns hash code based on values of statistics
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        hash code

      • getSumImpl

        public StorelessUnivariateStatistic getSumImpl()
        Returns the currently configured Sum implementation
        Returns:
        the StorelessUnivariateStatistic implementing the sum
        Since:
        1.2

      • setSumImpl

        public void setSumImpl​(StorelessUnivariateStatistic sumImpl)

        Sets the implementation for the Sum.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        sumImpl - the StorelessUnivariateStatistic instance to use for computing the Sum
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getSumsqImpl

        public StorelessUnivariateStatistic getSumsqImpl()
        Returns the currently configured sum of squares implementation
        Returns:
        the StorelessUnivariateStatistic implementing the sum of squares
        Since:
        1.2

      • setSumsqImpl

        public void setSumsqImpl​(StorelessUnivariateStatistic sumsqImpl)

        Sets the implementation for the sum of squares.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        sumsqImpl - the StorelessUnivariateStatistic instance to use for computing the sum of squares
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getMinImpl

        public StorelessUnivariateStatistic getMinImpl()
        Returns the currently configured minimum implementation
        Returns:
        the StorelessUnivariateStatistic implementing the minimum
        Since:
        1.2

      • setMinImpl

        public void setMinImpl​(StorelessUnivariateStatistic minImpl)

        Sets the implementation for the minimum.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        minImpl - the StorelessUnivariateStatistic instance to use for computing the minimum
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getMaxImpl

        public StorelessUnivariateStatistic getMaxImpl()
        Returns the currently configured maximum implementation
        Returns:
        the StorelessUnivariateStatistic implementing the maximum
        Since:
        1.2

      • setMaxImpl

        public void setMaxImpl​(StorelessUnivariateStatistic maxImpl)

        Sets the implementation for the maximum.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        maxImpl - the StorelessUnivariateStatistic instance to use for computing the maximum
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getSumLogImpl

        public StorelessUnivariateStatistic getSumLogImpl()
        Returns the currently configured sum of logs implementation
        Returns:
        the StorelessUnivariateStatistic implementing the log sum
        Since:
        1.2

      • setSumLogImpl

        public void setSumLogImpl​(StorelessUnivariateStatistic sumLogImpl)

        Sets the implementation for the sum of logs.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        sumLogImpl - the StorelessUnivariateStatistic instance to use for computing the log sum
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getGeoMeanImpl

        public StorelessUnivariateStatistic getGeoMeanImpl()
        Returns the currently configured geometric mean implementation
        Returns:
        the StorelessUnivariateStatistic implementing the geometric mean
        Since:
        1.2

      • setGeoMeanImpl

        public void setGeoMeanImpl​(StorelessUnivariateStatistic geoMeanImpl)

        Sets the implementation for the geometric mean.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        geoMeanImpl - the StorelessUnivariateStatistic instance to use for computing the geometric mean
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getMeanImpl

        public StorelessUnivariateStatistic getMeanImpl()
        Returns the currently configured mean implementation
        Returns:
        the StorelessUnivariateStatistic implementing the mean
        Since:
        1.2

      • setMeanImpl

        public void setMeanImpl​(StorelessUnivariateStatistic meanImpl)

        Sets the implementation for the mean.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        meanImpl - the StorelessUnivariateStatistic instance to use for computing the mean
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • getVarianceImpl

        public StorelessUnivariateStatistic getVarianceImpl()
        Returns the currently configured variance implementation
        Returns:
        the StorelessUnivariateStatistic implementing the variance
        Since:
        1.2

      • setVarianceImpl

        public void setVarianceImpl​(StorelessUnivariateStatistic varianceImpl)

        Sets the implementation for the variance.

        This method must be activated before any data has been added - i.e., before addValue has been used to add data; otherwise an IllegalStateException will be thrown.

        Parameters:
        varianceImpl - the StorelessUnivariateStatistic instance to use for computing the variance
        Throws:
        java.lang.IllegalStateException - if data has already been added (i.e if n > 0)
        Since:
        1.2

      • 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)
        Copies source to dest.

        Neither source nor dest can be null.

        Parameters:
        source - SummaryStatistics to copy
        dest - SummaryStatistics to copy to
        Throws:
        java.lang.NullPointerException - if either source or dest is null