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

Class FPGrowth.FPNode

java.lang.Object

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

Direct Known Subclasses:

FPGrowth.FPTree

Enclosing class:

FPGrowth

public static class FPGrowth.FPNode
extends Object

A single node of the FP tree.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FPGrowth.FPNode.Translator Translator class for tree printing.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) FPGrowth.FPNode[]	children Children.
(package private) int	count Key, weight, and number of children.
(package private) static FPGrowth.FPNode[]	EMPTY_CHILDREN Constant for leaf nodes.
(package private) int	INITIAL_SIZE Initial size, after sizes 0 and 1.
(package private) int	key Key, weight, and number of children.
(package private) int	numchildren Key, weight, and number of children.
(package private) FPGrowth.FPNode	parent Parent node and next in sequence.
(package private) FPGrowth.FPNode	sibling Parent node and next in sequence.
private static char[]	SPACES Buffer for indentation.

Constructor Summary

Constructors

Constructor and Description
FPNode(FPGrowth.FPNode parent, int key) Constructor.

Method Summary

Modifier and Type	Method and Description
void	appendTo(StringBuilder buf, FPGrowth.FPNode.Translator t) Debugging function: build a text representation of the tree.
private void	appendTo(StringBuilder buf, FPGrowth.FPNode.Translator t, int depth) Debugging function: build a text representation of the tree.
private void	ensureSize() Ensure we have enough storage.
void	insert(FPGrowth.FPTree tree, int[] buf, int i, int l, int weight) Insert an itemset into the tree.
void	reduceMemory() Release the memory occupied for the parent-to-child navigation, which is no longer needed after building the tree (only child-to-parent is needed in extracting itemsets).

Methods inherited from class java.lang.Object

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

Field Detail

parent

FPGrowth.FPNode parent

Parent node and next in sequence.

sibling

FPGrowth.FPNode sibling

Parent node and next in sequence.

key

int key

Key, weight, and number of children.

count

int count

Key, weight, and number of children.

numchildren

int numchildren

Key, weight, and number of children.

children

FPGrowth.FPNode[] children

Children.

EMPTY_CHILDREN

static final FPGrowth.FPNode[] EMPTY_CHILDREN

Constant for leaf nodes.

INITIAL_SIZE

final int INITIAL_SIZE

Initial size, after sizes 0 and 1.

See Also:

Constant Field Values

SPACES

private static final char[] SPACES

Buffer for indentation.

Constructor Detail

FPNode

public FPNode(FPGrowth.FPNode parent,
              int key)

Constructor.

Parameters:

parent - Parent node

key - Key

Method Detail

insert

public void insert(FPGrowth.FPTree tree,
                   int[] buf,
                   int i,
                   int l,
                   int weight)

Insert an itemset into the tree.

Parameters:

buf - Itemset buffer

i - Current index

l - Length

weight - Weight

ensureSize

private void ensureSize()

Ensure we have enough storage.

appendTo

public void appendTo(StringBuilder buf,
                     FPGrowth.FPNode.Translator t)

Debugging function: build a text representation of the tree.

Parameters:

buf - Output buffer

t - Translator to user-understandable items

appendTo

private void appendTo(StringBuilder buf,
                      FPGrowth.FPNode.Translator t,
                      int depth)

Debugging function: build a text representation of the tree.

Parameters:

buf - Output buffer

t - Translator to user-understandable items

depth - Current depth

reduceMemory

public void reduceMemory()

Release the memory occupied for the parent-to-child navigation, which is no longer needed after building the tree (only child-to-parent is needed in extracting itemsets).