Package weka.associations
Class CaRuleGeneration
- java.lang.Object
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- weka.associations.RuleGeneration
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- weka.associations.CaRuleGeneration
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- All Implemented Interfaces:
java.io.Serializable
,RevisionHandler
public class CaRuleGeneration extends RuleGeneration implements java.io.Serializable, RevisionHandler
Class implementing the rule generation procedure of the predictive apriori algorithm for class association rules. For association rules in gerneral the method is described in: T. Scheffer (2001). Finding Association Rules That Trade Support Optimally against Confidence. Proc of the 5th European Conf. on Principles and Practice of Knowledge Discovery in Databases (PKDD'01), pp. 424-435. Freiburg, Germany: Springer-Verlag.The implementation follows the paper expect for adding a rule to the output of the n best rules. A rule is added if: the expected predictive accuracy of this rule is among the n best and it is not subsumed by a rule with at least the same expected predictive accuracy (out of an unpublished manuscript from T. Scheffer).
- Version:
- $Revision: 1.4 $
- Author:
- Stefan Mutter (mutter@cs.waikato.ac.nz)
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description CaRuleGeneration(ItemSet itemSet)
Constructor
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static boolean
aSubsumesB(RuleItem a, RuleItem b)
Methods that decides whether or not rule a subsumes rule b.java.util.TreeSet
generateRules(int numRules, double[] midPoints, java.util.Hashtable priors, double expectation, Instances instances, java.util.TreeSet best, int genTime)
Generates all rules for an item set.java.lang.String
getRevision()
Returns the revision string.static FastVector
singleConsequence(Instances instances)
generates a consequence of length 1 for a class association rule.static FastVector
singletons(Instances instances)
Converts the header info of the given set of instances into a set of item sets (singletons).-
Methods inherited from class weka.associations.RuleGeneration
binomialDistribution, change, count, expectation, removeRedundant, singleConsequence
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Constructor Detail
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CaRuleGeneration
public CaRuleGeneration(ItemSet itemSet)
Constructor- Parameters:
itemSet
- the item set that forms the premise of the rule
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Method Detail
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generateRules
public java.util.TreeSet generateRules(int numRules, double[] midPoints, java.util.Hashtable priors, double expectation, Instances instances, java.util.TreeSet best, int genTime)
Generates all rules for an item set. The item set is the premise.- Overrides:
generateRules
in classRuleGeneration
- Parameters:
numRules
- the number of association rules the use wants to mine. This number equals the size n of the list of the best rules.midPoints
- the mid points of the intervalspriors
- Hashtable that contains the prior probabilitiesexpectation
- the minimum value of the expected predictive accuracy that is needed to get into the list of the best rulesinstances
- the instances for which association rules are generatedbest
- the list of the n best rules. The list is implemented as a TreeSetgenTime
- the maximum time of generation- Returns:
- all the rules with minimum confidence for the given item set
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aSubsumesB
public static boolean aSubsumesB(RuleItem a, RuleItem b)
Methods that decides whether or not rule a subsumes rule b. The defintion of subsumption is: Rule a subsumes rule b, if a subsumes b AND a has got least the same expected predictive accuracy as b.- Parameters:
a
- an association rule stored as a RuleItemb
- an association rule stored as a RuleItem- Returns:
- true if rule a subsumes rule b or false otherwise.
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singletons
public static FastVector singletons(Instances instances) throws java.lang.Exception
Converts the header info of the given set of instances into a set of item sets (singletons). The ordering of values in the header file determines the lexicographic order.- Parameters:
instances
- the set of instances whose header info is to be used- Returns:
- a set of item sets, each containing a single item
- Throws:
java.lang.Exception
- if singletons can't be generated successfully
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singleConsequence
public static FastVector singleConsequence(Instances instances)
generates a consequence of length 1 for a class association rule.- Parameters:
instances
- the instances under consideration- Returns:
- FastVector with consequences of length 1
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getRevision
public java.lang.String getRevision()
Returns the revision string.- Specified by:
getRevision
in interfaceRevisionHandler
- Overrides:
getRevision
in classRuleGeneration
- Returns:
- the revision
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