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java.lang.Objectorg.knime.base.node.mine.subgroupminer.apriori.ArrayApriori
public class ArrayApriori
The array apriori uses the
ArrayPrefixTreeNode
data structure to find frequent itemsets. Based on these it constructs a
prefix tree. In a prefix tree each child of an item has the path in the tree
to that item in common. The path is its prefix. The transactions are
processed, for each level once, by going to the node corresponding to first
item in the transaction, and process the rest of the transaction for that
node. Thus, there is no candidate generation.
Constructor Summary | |
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ArrayApriori(int bitSetLength,
int dbsize)
Creates an ArrayApriori instance with the bitset length, corresponding to the number of items. |
Method Summary | |
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void |
findFrequentItems(List<BitVectorValue> transactions)
First of all it starts to identify those items which are frequent at all. |
void |
findFrequentItemSets(List<BitVectorValue> transactions,
double minSupport,
int maxDepth,
FrequentItemSet.Type type,
ExecutionMonitor exec)
Finds the frequent itemsets by going down the tree until the current build level is reached, there it counts those items which are present in the transaction. |
List<AssociationRule> |
getAssociationRules(double confidence)
Returns the association rules generated from the found frequent itemsets with the passed minimal confidence. |
List<FrequentItemSet> |
getFrequentItemSets(FrequentItemSet.Type type)
Returns the found frequent itemsets according to their type, which can either be FREE, CLOSED or MAXIMAL. |
void |
setMinSupport(double minSupport)
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Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public ArrayApriori(int bitSetLength, int dbsize)
bitSetLength
- the number of itemsdbsize
- the number of transactionsMethod Detail |
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public void setMinSupport(double minSupport)
minSupport
- the minimum supportpublic void findFrequentItems(List<BitVectorValue> transactions)
transactions
- the database as bitsetspublic void findFrequentItemSets(List<BitVectorValue> transactions, double minSupport, int maxDepth, FrequentItemSet.Type type, ExecutionMonitor exec) throws CanceledExecutionException
findFrequentItemSets
in interface AprioriAlgorithm
transactions
- a list of BitSets representing the bitvectors, thus,
corresponding to the whole databaseminSupport
- the minimum support as an absolute valuemaxDepth
- the maximal length of an itemsettype
- the desired type of the frequent itemsetsexec
- the execution monitor
CanceledExecutionException
- if the execution was cancelledpublic List<AssociationRule> getAssociationRules(double confidence)
getAssociationRules
in interface AprioriAlgorithm
confidence
- the desired minimal confidence of the rules
public List<FrequentItemSet> getFrequentItemSets(FrequentItemSet.Type type)
getFrequentItemSets
in interface AprioriAlgorithm
type
- the desired type, either free, closed or maximal
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