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

Class Itemset

java.lang.Object

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

All Implemented Interfaces:

java.lang.Comparable<Itemset>

Direct Known Subclasses:

AssociationRuleGeneration.PartialItemset, DenseItemset, OneItemset, SmallDenseItemset, SparseItemset

public abstract class Itemset
extends java.lang.Object
implements java.lang.Comparable<Itemset>

Frequent itemset.

Since:

0.7.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	support Support for this itemset.

Constructor Summary

Constructors

Constructor and Description
Itemset()

Method Summary

Modifier and Type	Method and Description
java.lang.StringBuilder	appendItemsTo(java.lang.StringBuilder buf, VectorFieldTypeInformation<BitVector> meta) Only append the items to a string buffer.
java.lang.StringBuilder	appendTo(java.lang.StringBuilder buf, VectorFieldTypeInformation<BitVector> meta) Append items and support to a string buffer.
protected static int	compareLexicographical(Itemset a, Itemset o) Robust compare using the iterators, lexicographical only!
int	compareTo(Itemset o)
boolean	containedIn(SparseNumberVector bv) Test whether the itemset is contained in a bit vector.
boolean	equals(java.lang.Object obj)
int	getSupport() Get item support.
int	hashCode() Deprecated. Itemsets MUST NOT BE USED IN HASH MAPS.
int	increaseSupport() Increase the support of the itemset.
abstract int	iter() Get an iterator over items, usually the position within an array.
abstract int	iterAdvance(int iter) Advance the iterator to the next position.
abstract int	iterDim(int iter) Item at the iterator position.
abstract boolean	iterValid(int iter) Check if the iterator position is valid.
abstract int	length() Itemset length.
static long[]	toBitset(Itemset i, long[] bits) Get the items.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

support

int support

Support for this itemset.

Constructor Detail

Itemset

public Itemset()

Method Detail

increaseSupport

public int increaseSupport()

Increase the support of the itemset.

Returns:

New support.

getSupport

public int getSupport()

Get item support.

Returns:

Support

containedIn

public boolean containedIn(SparseNumberVector bv)

Test whether the itemset is contained in a bit vector.

Parameters:

bv - Bit vector

Returns:

true when the itemset is contained in this vector.

length

public abstract int length()

Itemset length.

Returns:

Itemset length

toBitset

public static long[] toBitset(Itemset i,
                              long[] bits)

Get the items.

Parameters:

i - Itemset

bits - Output bitset (must be zeros)

Returns:

Output bitset

iter

public abstract int iter()

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.
 }
 
 

Returns:

Iterator

iterAdvance

public abstract int iterAdvance(int iter)

Advance the iterator to the next position.

Parameters:

iter - Iterator

Returns:

New iterator position

iterValid

public abstract boolean iterValid(int iter)

Check if the iterator position is valid.

Parameters:

iter - Iterator

Returns:

true if the position is valid.

iterDim

public abstract int iterDim(int iter)

Item at the iterator position.

Parameters:

iter - Iterator

Returns:

Current item

compareTo

public int compareTo(Itemset o)

Specified by:

compareTo in interface java.lang.Comparable<Itemset>

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

@Deprecated
public int hashCode()

Deprecated. Itemsets MUST NOT BE USED IN HASH MAPS.

Overrides:

hashCode in class java.lang.Object

compareLexicographical

protected static int compareLexicographical(Itemset a,
                                            Itemset o)

Robust compare using the iterators, lexicographical only! Note: This does NOT take length into account.

Parameters:

o - Other itemset.

Returns:

Comparison result.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

appendTo

public final java.lang.StringBuilder appendTo(java.lang.StringBuilder buf,
                                              VectorFieldTypeInformation<BitVector> meta)

Append items and support to a string buffer.

Parameters:

buf - Buffer

meta - Relation metadata (for labels)

Returns:

String buffer for chaining.

appendItemsTo

public java.lang.StringBuilder appendItemsTo(java.lang.StringBuilder buf,
                                             VectorFieldTypeInformation<BitVector> meta)

Only append the items to a string buffer.

Parameters:

buf - Buffer

meta - Relation metadata (for labels)

Returns:

String buffer for chaining.