smile.association

Class FPTree

java.lang.Object

smile.association.FPTree

public class FPTree
extends java.lang.Object

FP-tree data structure used in FP-growth (frequent pattern growth) algorithm for frequent item set mining. An FP-tree is basically a prefix tree for the transactions. That is, each path represents a set of transactions that share the same prefix, each node corresponds to one item. In addition, all nodes referring to the same item are linked together in a list, so that all transactions containing a specific item can easily be found and counted by traversing this list. The list can be accessed through a head element, which also states the total number of occurrences of the item in the database.

Method Summary

Modifier and Type	Method and Description
int	minSupport() Returns the required minimum support of item sets in terms of frequency.
static FPTree	of(double minSupport, int[][] itemsets) One-step construction of FP-tree if the database is available in main memory.
static FPTree	of(double minSupport, java.util.function.Supplier<java.util.stream.Stream<int[]>> supplier) One-step construction of FP-tree if the database is available as stream.
static FPTree	of(int minSupport, int[][] itemsets) One-step construction of FP-tree if the database is available in main memory.
static FPTree	of(int minSupport, java.util.function.Supplier<java.util.stream.Stream<int[]>> supplier) One-step construction of FP-tree if the database is available as stream.
int	size() Returns the number transactions in the database.

Methods inherited from class java.lang.Object

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

Method Detail

of

public static FPTree of(int minSupport,
                        java.util.function.Supplier<java.util.stream.Stream<int[]>> supplier)

One-step construction of FP-tree if the database is available as stream.

Parameters:

minSupport - the required minimum support of item sets in terms of frequency.

supplier - a supplier provides an itemset stream. For example, a code block to open a file and parse lines into a stream of itemsets. This function will be called twice.

Returns:

a full built FP-tree.

of

public static FPTree of(double minSupport,
                        java.util.function.Supplier<java.util.stream.Stream<int[]>> supplier)

One-step construction of FP-tree if the database is available as stream.

Parameters:

minSupport - the required minimum support of item sets in terms of percentage.

supplier - a supplier provides an itemset stream. For example, a code block to open a file and parse lines into a stream of itemsets. This function will be called twice.

Returns:

a full built FP-tree.

of

public static FPTree of(int minSupport,
                        int[][] itemsets)

One-step construction of FP-tree if the database is available in main memory.

Parameters:

itemsets - the item set database. Each row is a item set, which may have different length. The item identifiers have to be in [0, n), where n is the number of items. Item set should NOT contain duplicated items. Note that it is reordered after the call.

minSupport - the required minimum support of item sets in terms of frequency.

of

public static FPTree of(double minSupport,
                        int[][] itemsets)

One-step construction of FP-tree if the database is available in main memory.

Parameters:

itemsets - the item set database. Each row is a item set, which may have different length. The item identifiers have to be in [0, n), where n is the number of items. Item set should NOT contain duplicated items. Note that it is reordered after the call.

minSupport - the required minimum support of item sets in terms of percentage.

size

public int size()

Returns the number transactions in the database.

minSupport

public int minSupport()

Returns the required minimum support of item sets in terms of frequency.