CLOSET

Author	Lily Dong
Creation date	06/01/2011
Firing policy	all
Package	org.seasr.meandre.components.discovery.ruleassociation.fptree

DESCRIPTION

Overview: This module implements the CLOSET algorithm to generate closed frequent itemsets consisting of items that occur in a sufficient number of examples to satisfy the minimum support criteria.

Detailed Description: This module takes an FPProb object that has been generated by a Large Item Table Generator module and uses the CLOSET algorithm to find the combinations of items that satisfy a minimum support criteria. An item is an [attribute,value] pair that occurs in the set of examples being mined. The user controls the support criteria via the property of LargeItemTableGenerator that specifies the number of all examples that must contain a given combination of items before that combination is included in the generated output. Each combination of items that satisfies the Minimum Support % is called a Frequent Itemset. The CLOSET algorithm further restricts the itemsets returned by returning only the closed sets. (see Han 2000)

References: For more information on the CLOSET frequent pattern mining algorithm, see " CLOSET: An Efficient Algorithm for Mining Frequent Closed Itemsets ", Jian Pei, Jiawei Han, Runying Mao, 2000.

Data Type Restrictions: While this module can operate on attributes of any datatype, in practice it is usually infeasible to use it with continuous-valued attributes. The module considers each [attribute,value] pair that occurs in the examples individually when building the frequent itemsets. Continuous attributes (and categorical attributes with a large number of values) are less likely to meet the Minimum Support requirements and can result in unacceptably long execution time.

INPUTS

Name	Description	Example
fp_prob	The input parameters encapsulated in an FPProb object.

OUTPUTS

Name	Description	Example
patterns	List of all closed frequent patterns discovered.
error	This port is used to output any unhandled errors encountered during the execution of this component

PROPERTIES

Name	Description	Default value
_debug_level	Controls the verbosity of debug messages printed by the component during execution. Possible values are: off, severe, warning, info, config, fine, finer, finest, all Append ',mirror' to any of the values above to mirror that output to the server logs.	info
_ignore_errors	Set to 'true' to ignore all unhandled exceptions and prevent the flow from being terminated. Setting this property to 'false' will result in the flow being terminated in the event an unhandled exception is thrown during the execution of this component	false