Class SumOfLogs
- java.lang.Object
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- org.apache.commons.math4.legacy.stat.descriptive.AbstractStorelessUnivariateStatistic
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- org.apache.commons.math4.legacy.stat.descriptive.summary.SumOfLogs
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- All Implemented Interfaces:
MathArrays.Function,StorelessUnivariateStatistic,UnivariateStatistic
public class SumOfLogs extends AbstractStorelessUnivariateStatistic
Returns the sum of the natural logs for this collection of values.Uses
JdkMath.log(double)to compute the logs. Therefore,- If any of values are < 0, the result is
NaN. - If all values are non-negative and less than
Double.POSITIVE_INFINITY, but at least one value is 0, the result isDouble.NEGATIVE_INFINITY. - If both
Double.POSITIVE_INFINITYandDouble.NEGATIVE_INFINITYare among the values, the result isNaN.
Note that this implementation is not synchronized. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the
increment()orclear()method, it must be synchronized externally.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclear()Clears the internal state of the Statistic.SumOfLogscopy()Returns a copy of the statistic with the same internal state.static voidcopy(SumOfLogs source, SumOfLogs dest)Copies source to dest.doubleevaluate(double[] values, int begin, int length)Returns the sum of the natural logs of the entries in the specified portion of the input array, orDouble.NaNif the designated subarray is empty.longgetN()Returns the number of values that have been added.doublegetResult()Returns the current value of the Statistic.voidincrement(double d)Updates the internal state of the statistic to reflect the addition of the new value.-
Methods inherited from class org.apache.commons.math4.legacy.stat.descriptive.AbstractStorelessUnivariateStatistic
equals, evaluate, hashCode, incrementAll, incrementAll
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Constructor Detail
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SumOfLogs
public SumOfLogs()
Create a SumOfLogs instance.
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SumOfLogs
public SumOfLogs(SumOfLogs original) throws NullArgumentException
Copy constructor, creates a newSumOfLogsidentical to theoriginal.- Parameters:
original- theSumOfLogsinstance to copy- Throws:
NullArgumentException- if original is null
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Method Detail
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increment
public void increment(double d)
Updates the internal state of the statistic to reflect the addition of the new value.- Specified by:
incrementin interfaceStorelessUnivariateStatistic- Specified by:
incrementin classAbstractStorelessUnivariateStatistic- Parameters:
d- the new value.
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getResult
public double getResult()
Returns the current value of the Statistic.- Specified by:
getResultin interfaceStorelessUnivariateStatistic- Specified by:
getResultin classAbstractStorelessUnivariateStatistic- Returns:
- value of the statistic,
Double.NaNif it has been cleared or just instantiated.
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getN
public long getN()
Returns the number of values that have been added.- Returns:
- the number of values.
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clear
public void clear()
Clears the internal state of the Statistic.- Specified by:
clearin interfaceStorelessUnivariateStatistic- Specified by:
clearin classAbstractStorelessUnivariateStatistic
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evaluate
public double evaluate(double[] values, int begin, int length) throws MathIllegalArgumentException
Returns the sum of the natural logs of the entries in the specified portion of the input array, orDouble.NaNif the designated subarray is empty.Throws
MathIllegalArgumentExceptionif the array is null.See
SumOfLogs.- Specified by:
evaluatein interfaceMathArrays.Function- Specified by:
evaluatein interfaceUnivariateStatistic- Overrides:
evaluatein classAbstractStorelessUnivariateStatistic- Parameters:
values- the input arraybegin- index of the first array element to includelength- the number of elements to include- Returns:
- the sum of the natural logs of the values or 0 if length = 0
- Throws:
MathIllegalArgumentException- if the array is null or the array index parameters are not valid- See Also:
UnivariateStatistic.evaluate(double[], int, int)
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copy
public SumOfLogs copy()
Returns a copy of the statistic with the same internal state.- Specified by:
copyin interfaceStorelessUnivariateStatistic- Specified by:
copyin interfaceUnivariateStatistic- Specified by:
copyin classAbstractStorelessUnivariateStatistic- Returns:
- a copy of the statistic
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copy
public static void copy(SumOfLogs source, SumOfLogs dest) throws NullArgumentException
Copies source to dest.Neither source nor dest can be null.
- Parameters:
source- SumOfLogs to copydest- SumOfLogs to copy to- Throws:
NullArgumentException- if either source or dest is null
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