Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## org.apache.commons.math.stat.descriptive.summary
Class SumOfSquares

    java.lang.Object
      org.apache.commons.math.stat.descriptive.AbstractUnivariateStatistic
          org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic
              org.apache.commons.math.stat.descriptive.summary.SumOfSquares

All Implemented Interfaces:
  Serializable, StorelessUnivariateStatistic, UnivariateStatistic

public class SumOfSquares
extends AbstractStorelessUnivariateStatistic
implements Serializable

Returns the sum of the squares of the available values.

If there are no values in the dataset, or any of the values are `NaN`, then `NaN` is returned.

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()` or `clear()` method, it must be synchronized externally.

Version:
  $Revision: 1.1 $ $Date: 2004/10/08 05:08:18 $
See Also:
  Serialized Form

Field Summary
`(package private) static long` | `serialVersionUID` Serializable version identifier

Constructor Summary
`SumOfSquares()` Create a SumOfSquares instance

Method Summary
`void` | `clear()` Clears the internal state of the Statistic
`double` | `evaluate(double[] values, int begin, int length)` Returns the sum of the squares of the entries in the specified portion of the input array, or `Double.NaN` if the designated subarray is empty.
`long` | `getN()` Returns the number of values that have been added.
`double` | `getResult()` Returns the current value of the Statistic.
`void` | `increment(double d)` Updates the internal state of the statistic to reflect the addition of the new value.

Methods inherited from class org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic
`equals, evaluate, hashCode, incrementAll, incrementAll`

Methods inherited from class org.apache.commons.math.stat.descriptive.AbstractUnivariateStatistic
`test`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### serialVersionUID

    static final long serialVersionUID

  Serializable version identifier

  See Also:
    Constant Field Values

Constructor Detail

### SumOfSquares

    public SumOfSquares()

  Create a SumOfSquares instance

Method Detail

### increment

    public void increment(double d)

  Description copied from interface: `StorelessUnivariateStatistic`
  Updates the internal state of the statistic to reflect the addition of the new value.

  Specified by:
    `increment` in interface `StorelessUnivariateStatistic`
  Specified by:
    `increment` in class `AbstractStorelessUnivariateStatistic`
  See Also:
    `StorelessUnivariateStatistic.increment(double)`

### getResult

    public double getResult()

  Description copied from interface: `StorelessUnivariateStatistic`
  Returns the current value of the Statistic.

  Specified by:
    `getResult` in interface `StorelessUnivariateStatistic`
  Specified by:
    `getResult` in class `AbstractStorelessUnivariateStatistic`
  See Also:
    `StorelessUnivariateStatistic.getResult()`

### getN

    public long getN()

  Description copied from interface: `StorelessUnivariateStatistic`
  Returns the number of values that have been added.

  Specified by:
    `getN` in interface `StorelessUnivariateStatistic`
  Returns:
    the number of values.
  See Also:
    `StorelessUnivariateStatistic.getN()`

### clear

    public void clear()

  Description copied from interface: `StorelessUnivariateStatistic`
  Clears the internal state of the Statistic

  Specified by:
    `clear` in interface `StorelessUnivariateStatistic`
  Specified by:
    `clear` in class `AbstractStorelessUnivariateStatistic`
  See Also:
    `StorelessUnivariateStatistic.clear()`

### evaluate

    public double evaluate(double[] values,
                           int begin,
                           int length)

  Returns the sum of the squares of the entries in the specified portion of the input array, or `Double.NaN` if the designated subarray is empty.

  Throws `IllegalArgumentException` if the array is null.

  Specified by:
    `evaluate` in interface `UnivariateStatistic`
  Overrides:
    `evaluate` in class `AbstractStorelessUnivariateStatistic`
  Parameters:
    `values` - the input array
    `begin` - index of the first array element to include
    `length` - the number of elements to include
  Returns:
    the sum of the squares of the values or Double.NaN if length = 0
  Throws:
    `IllegalArgumentException` - if the array is null or the array index parameters are not valid
  See Also:
    `UnivariateStatistic.evaluate(double[], int, int)`

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

Copyright © 2003-2004 The Apache Software Foundation. All Rights Reserved.