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java.lang.Object de.lmu.ifi.dbs.elki.math.Mean
@Reference(authors="B. P. Welford", title="Note on a method for calculating corrected sums of squares and products", booktitle="Technometrics 4(3)") public class Mean
Compute the mean using a numerically stable online algorithm. This class can repeatedly be fed with data using the add() methods, the resulting values for mean can be queried at any time using getMean(). Trivial code, but replicated a lot. The class is final so it should come at low cost. Related Literature:
B. P. Welford
Note on a method for calculating corrected sums of squares and products
in: Technometrics 4(3)
D.H.D. West
Updating Mean and Variance Estimates: An Improved Method
In: Communications of the ACM, Volume 22 Issue 9
Field Summary | |
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protected double |
mean
Mean of values |
protected double |
wsum
Weight sum (number of samples) |
Constructor Summary | |
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Mean()
Empty constructor |
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Mean(Mean other)
Constructor from other instance |
Method Summary | |
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double |
getCount()
Get the number of points the average is based on. |
double |
getMean()
Return mean |
static Mean[] |
newArray(int dimensionality)
Create and initialize a new array of MeanVariance |
void |
put(double val)
Add a single value with weight 1.0 |
void |
put(double val,
double weight)
Add data with a given weight. |
void |
put(Mean other)
Join the data of another MeanVariance instance. |
String |
toString()
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Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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protected double mean
protected double wsum
Constructor Detail |
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public Mean()
public Mean(Mean other)
other
- other instance to copy data from.Method Detail |
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public void put(double val)
val
- Valuepublic void put(double val, double weight)
val
- dataweight
- weightpublic void put(Mean other)
other
- Data to join withpublic double getCount()
public double getMean()
public static Mean[] newArray(int dimensionality)
dimensionality
- Dimensionality
public String toString()
toString
in class Object
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