Class LabeledItemSet

  • All Implemented Interfaces:
    java.io.Serializable, RevisionHandler

    public class LabeledItemSet
    extends ItemSet
    implements java.io.Serializable, RevisionHandler
    Class for storing a set of items together with a class label. Item sets are stored in a lexicographic order, which is determined by the header information of the set of instances used for generating the set of items. All methods in this class assume that item sets are stored in lexicographic order. The class provides the methods used for item sets in class association rule mining. Because every item set knows its class label the training set can be splitted up virtually.
    Version:
    $Revision: 1.5 $
    Author:
    Stefan Mutter (mutter@cs.waikato.ac.nz)
    See Also:
    Serialized Form
    • Constructor Detail

      • LabeledItemSet

        public LabeledItemSet​(int totalTrans,
                              int classLabel)
        Constructor
        Parameters:
        totalTrans - the total number of transactions
        classLabel - the class lebel
    • Method Detail

      • deleteItemSets

        public static FastVector deleteItemSets​(FastVector itemSets,
                                                int minSupport,
                                                int maxSupport)
        Deletes all item sets that don't have minimum support and have more than maximum support
        Parameters:
        maxSupport - the maximum support
        itemSets - the set of item sets to be pruned
        minSupport - the minimum number of transactions to be covered
        Returns:
        the reduced set of item sets
      • equals

        public final boolean equals​(java.lang.Object itemSet)
        Tests if two item sets are equal.
        Overrides:
        equals in class ItemSet
        Parameters:
        itemSet - another item set
        Returns:
        true if this item set contains the same items as the given one
      • equalCondset

        public final boolean equalCondset​(java.lang.Object itemSet)
        Compares two item sets
        Parameters:
        itemSet - an item set
        Returns:
        true if the the item sets are equal, false otherwise
      • getHashtable

        public static java.util.Hashtable getHashtable​(FastVector itemSets,
                                                       int initialSize)
        Return a hashtable filled with the given item sets.
        Parameters:
        itemSets - the set of item sets to be used for filling the hash table
        initialSize - the initial size of the hashtable
        Returns:
        the generated hashtable
      • mergeAllItemSets

        public static FastVector mergeAllItemSets​(FastVector itemSets,
                                                  int size,
                                                  int totalTrans)
        Merges all item sets in the set of (k-1)-item sets to create the (k)-item sets and updates the counters.
        Parameters:
        totalTrans - the total number of transactions
        itemSets - the set of (k-1)-item sets
        size - the value of (k-1)
        Returns:
        the generated (k)-item sets
      • divide

        public static Instances divide​(Instances instances,
                                       boolean invert)
                                throws java.lang.Exception
        Splits the class attribute away. Depending on the invert flag, the instances without class attribute or only the class attribute of all instances is returned
        Parameters:
        instances - the instances
        invert - flag; if true only the class attribute remains, otherweise the class attribute is the only attribute that is deleted.
        Returns:
        Instances without the class attribute or instances with only the class attribute
        Throws:
        java.lang.Exception - exception if instances cannot be splitted
      • singletons

        public static FastVector singletons​(Instances instancesNoClass,
                                            Instances classes)
                                     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. Each item set knows its class label.
        Parameters:
        instancesNoClass - instances without the class attribute
        classes - the values of the class attribute sorted according to instances
        Returns:
        a set of item sets, each containing a single item
        Throws:
        java.lang.Exception - if singletons can't be generated successfully
      • pruneItemSets

        public static FastVector pruneItemSets​(FastVector toPrune,
                                               java.util.Hashtable kMinusOne)
        Prunes a set of (k)-item sets using the given (k-1)-item sets.
        Parameters:
        toPrune - the set of (k)-item sets to be pruned
        kMinusOne - the (k-1)-item sets to be used for pruning
        Returns:
        the pruned set of item sets
      • support

        public final int support()
        Outputs the support for an item set.
        Overrides:
        support in class ItemSet
        Returns:
        the support
      • upDateCounter

        public final void upDateCounter​(Instance instanceNoClass,
                                        Instance instanceClass)
        Updates counter of item set with respect to given transaction.
        Parameters:
        instanceNoClass - instances without the class attribute
        instanceClass - the values of the class attribute sorted according to instances
      • upDateCounters

        public static void upDateCounters​(FastVector itemSets,
                                          Instances instancesNoClass,
                                          Instances instancesClass)
        Updates counter of a specific item set
        Parameters:
        itemSets - an item sets
        instancesNoClass - instances without the class attribute
        instancesClass - the values of the class attribute sorted according to instances
      • generateRules

        public final FastVector[] generateRules​(double minConfidence,
                                                boolean noPrune)
        Generates rules out of item sets
        Parameters:
        minConfidence - the minimum confidence
        noPrune - flag indicating whether the rules are pruned accoridng to the minimum confidence value
        Returns:
        a set of rules