uk.ac.starlink.ttools.filter
Class UnivariateStats

java.lang.Object
  uk.ac.starlink.ttools.filter.UnivariateStats

public abstract class UnivariateStats
extends Object

Calculates univariate statistics for a variable. Feed data to an instance of this object by repeatedly calling acceptDatum(java.lang.Object) and then call the various accessor methods to get accumulated values.

Since:

27 Apr 2006

Author:

Mark Taylor

Constructor Summary

UnivariateStats()

Method Summary

abstract void	acceptDatum(Object value) Submits a single value to the statistics accumulator.
static UnivariateStats	createStats(Class clazz) Factory method to construct an instance of this class for accumulating particular types of values.
abstract long	getCount() Returns the number of good (non-null) values accumulated.
abstract Number	getMaximum() Returns the numeric maximum value submitted.
abstract long	getMaxPos() Returns the sequence number of the maximum value submitted.
abstract Number	getMinimum() Returns the numeric minimum value submitted.
abstract long	getMinPos() Returns the sequence number of the minimum value submitted.
abstract double	getSum() Returns the numeric sum of values accumulated.
abstract double	getSum2() Returns the sum of squares of values accumulated.
abstract double	getSum3() Returns the sum of cubes of values accumulated.
abstract double	getSum4() Returns the sum of fourth powers of values accumulated.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UnivariateStats

public UnivariateStats()

Method Detail

acceptDatum

public abstract void acceptDatum(Object value)

Submits a single value to the statistics accumulator. The submitted value should be of a type compatible with the class type of this Stats object.

Parameters:

value - value object

getCount

public abstract long getCount()

Returns the number of good (non-null) values accumulated.

Returns:

good value count

getSum

public abstract double getSum()

Returns the numeric sum of values accumulated.

Returns:

sum of values

getSum2

public abstract double getSum2()

Returns the sum of squares of values accumulated.

Returns:

sum of squared values

getSum3

public abstract double getSum3()

Returns the sum of cubes of values accumulated.

Returns:

sum of cubed values

getSum4

public abstract double getSum4()

Returns the sum of fourth powers of values accumulated.

Returns:

sum of fourth powers

getMinimum

public abstract Number getMinimum()

Returns the numeric minimum value submitted.

Returns:

minimum

getMaximum

public abstract Number getMaximum()

Returns the numeric maximum value submitted.

Returns:

maximum

getMinPos

public abstract long getMinPos()

Returns the sequence number of the minimum value submitted. Returns -1 if there is no minimum.

Returns:

row index of minimum

getMaxPos

public abstract long getMaxPos()

Returns the sequence number of the maximum value submitted. Returns -1 if there is no maximum.

Returns:

row index of maximum

createStats

public static UnivariateStats createStats(Class clazz)

Factory method to construct an instance of this class for accumulating particular types of values.

Parameters:

clazz - class of which all submitted values will be instances of (if they're not null)