ca.pfv.spmf.algorithms.frequentpatterns.charm

Class AlgoCharm_Bitset

java.lang.Object

ca.pfv.spmf.algorithms.frequentpatterns.charm.AlgoCharm_Bitset

Direct Known Subclasses:

AlgoDCharm_Bitset

public class AlgoCharm_Bitset
extends java.lang.Object

This is a new implementation of the CHARM algorithm (2014) that relies on bitsets to implement tidsets. Charm was proposed by ZAKI (2001).

See this article for details about CHARM:

Zaki, M. J., & Hsiao, C. J. (2002). CHARM: An Efficient Algorithm for Closed Itemset Mining. In SDM (Vol. 2, pp. 457-473).

This version saves the result to a file or keep it into memory if no output path is provided by the user to the runAlgorithm method().

See Also:

TriangularMatrix, TransactionDatabase, Itemset, Itemsets

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	AlgoCharm_Bitset.BitSetSupport Anonymous inner class to store a bitset and its cardinality.

Constructor Summary

Constructors

Constructor and Description
AlgoCharm_Bitset() Default constructor

Method Summary

Modifier and Type	Method and Description
Itemsets	getClosedItemsets() Get the set of frequent itemsets.
void	printStats() Print statistics about the algorithm execution to System.out.
Itemsets	runAlgorithm(java.lang.String output, TransactionDatabase database, double minsup, boolean useTriangularMatrixOptimization, int hashTableSize) Run the algorithm and save the output to a file or keep it into memory.

Methods inherited from class java.lang.Object

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

Constructor Detail

AlgoCharm_Bitset

public AlgoCharm_Bitset()

Default constructor

Method Detail

runAlgorithm

public Itemsets runAlgorithm(java.lang.String output,
                             TransactionDatabase database,
                             double minsup,
                             boolean useTriangularMatrixOptimization,
                             int hashTableSize)
                      throws java.io.IOException

Run the algorithm and save the output to a file or keep it into memory.

Parameters:

database - a transaction database

output - an output file path for writing the result or if null the result is saved into memory and returned

minsup - the minimum support

useTriangularMatrixOptimization - if true the triangular matrix optimization will be applied.

hashTableSize - the size of the hashtable (e.g. 10,000).

Returns:

the set of closed itemsets found if the result is kept into memory or null otherwise.

Throws:

java.io.IOException - exception if error while writing the file.

printStats

public void printStats()

Print statistics about the algorithm execution to System.out.

getClosedItemsets

public Itemsets getClosedItemsets()

Get the set of frequent itemsets.

Returns:

the frequent itemsets (Itemsets).