org.apache.mahout.cf.taste.impl.common
Class FullRunningAverageAndStdDev
java.lang.Object
org.apache.mahout.cf.taste.impl.common.FullRunningAverage
org.apache.mahout.cf.taste.impl.common.FullRunningAverageAndStdDev
- All Implemented Interfaces:
- Serializable, RunningAverage, RunningAverageAndStdDev
public final class FullRunningAverageAndStdDev
- extends FullRunningAverage
- implements RunningAverageAndStdDev
Extends FullRunningAverage
to add a running standard deviation computation.
Uses Welford's method, as described at http://www.johndcook.com/standard_deviation.html
- See Also:
- Serialized Form
FullRunningAverageAndStdDev
public FullRunningAverageAndStdDev()
FullRunningAverageAndStdDev
public FullRunningAverageAndStdDev(int count,
double average,
double mk,
double sk)
getMk
public double getMk()
getSk
public double getSk()
getStandardDeviation
public double getStandardDeviation()
- Specified by:
getStandardDeviation
in interface RunningAverageAndStdDev
- Returns:
- standard deviation of data
addDatum
public void addDatum(double datum)
- Specified by:
addDatum
in interface RunningAverage
- Overrides:
addDatum
in class FullRunningAverage
- Parameters:
datum
- new item to add to the running average
removeDatum
public void removeDatum(double datum)
- Specified by:
removeDatum
in interface RunningAverage
- Overrides:
removeDatum
in class FullRunningAverage
- Parameters:
datum
- item to remove to the running average
changeDatum
public void changeDatum(double delta)
- Specified by:
changeDatum
in interface RunningAverage
- Overrides:
changeDatum
in class FullRunningAverage
- Parameters:
delta
- amount by which to change a datum in the running average
- Throws:
UnsupportedOperationException
inverse
public RunningAverageAndStdDev inverse()
- Specified by:
inverse
in interface RunningAverage
- Specified by:
inverse
in interface RunningAverageAndStdDev
- Overrides:
inverse
in class FullRunningAverage
- Returns:
- a (possibly immutable) object whose average is the negative of this object's
toString
public String toString()
- Overrides:
toString
in class FullRunningAverage
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