de.lmu.ifi.dbs.elki.algorithm.itemsetmining

Class SparseItemset

java.lang.Object

de.lmu.ifi.dbs.elki.algorithm.itemsetmining.Itemset

de.lmu.ifi.dbs.elki.algorithm.itemsetmining.SparseItemset

All Implemented Interfaces:

java.lang.Comparable<Itemset>

public class SparseItemset
extends Itemset

Frequent itemset, sparse representation.

Since:

0.7.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int[]	indices Items, as indexes.

Fields inherited from class de.lmu.ifi.dbs.elki.algorithm.itemsetmining.Itemset

support

Constructor Summary

Constructors

Constructor and Description
SparseItemset(int[] indices) Constructor.
SparseItemset(int[] indices, int support) Constructor with initial support.
SparseItemset(OneItemset ii, OneItemset ij) Constructor from existing itemsets.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Itemset o)
int	iter() Get an iterator over items, usually the position within an array.
int	iterAdvance(int iter) Advance the iterator to the next position.
int	iterDim(int iter) Item at the iterator position.
boolean	iterValid(int iter) Check if the iterator position is valid.
int	length() Itemset length.
boolean	prefixTest(SparseItemset other) Perform the prefix test for sparse itemset.

Methods inherited from class de.lmu.ifi.dbs.elki.algorithm.itemsetmining.Itemset

appendItemsTo, appendTo, compareLexicographical, containedIn, equals, getSupport, hashCode, increaseSupport, toBitset, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

indices

int[] indices

Items, as indexes.

Constructor Detail

SparseItemset

public SparseItemset(int[] indices)

Constructor.

Parameters:

indices - Items

SparseItemset

public SparseItemset(int[] indices,
                     int support)

Constructor with initial support.

Parameters:

indices - Items

support - Support

SparseItemset

public SparseItemset(OneItemset ii,
                     OneItemset ij)

Constructor from existing itemsets.

Parameters:

ii - First 1-itemset

ij - Second 1-itemset

Method Detail

length

public int length()

Description copied from class: Itemset

Itemset length.

Specified by:

length in class Itemset

Returns:

Itemset length

iter

public int iter()

Description copied from class: Itemset

Get an iterator over items, usually the position within an array. Intended usage:

 
 for (int iter = v.iter(); v.iterValid(iter); iter = v.iterAdvance(iter)) {
   final int item = v.iterItem(iter);
   // Do something.
 }
 
 

Specified by:

iter in class Itemset

Returns:

Iterator

iterValid

public boolean iterValid(int iter)

Description copied from class: Itemset

Check if the iterator position is valid.

Specified by:

iterValid in class Itemset

Parameters:

iter - Iterator

Returns:

true if the position is valid.

iterAdvance

public int iterAdvance(int iter)

Description copied from class: Itemset

Advance the iterator to the next position.

Specified by:

iterAdvance in class Itemset

Parameters:

iter - Iterator

Returns:

New iterator position

iterDim

public int iterDim(int iter)

Description copied from class: Itemset

Item at the iterator position.

Specified by:

iterDim in class Itemset

Parameters:

iter - Iterator

Returns:

Current item

compareTo

public int compareTo(Itemset o)

Specified by:

compareTo in interface java.lang.Comparable<Itemset>

Overrides:

compareTo in class Itemset

prefixTest

public boolean prefixTest(SparseItemset other)

Perform the prefix test for sparse itemset.

Parameters:

other - Other itemset

Returns:

true iff the first n-1 items agree.