org.apache.mahout.fpm.pfpgrowth.fpgrowth2
Class FPTree

java.lang.Object
  extended by org.apache.mahout.fpm.pfpgrowth.fpgrowth2.FPTree

public final class FPTree
extends Object

A straightforward implementation of FPTrees as described in Han et. al.


Nested Class Summary
static class FPTree.FPNode
           
 
Constructor Summary
FPTree(long[] attrCounts, long minSupport)
          Creates an FPTree using the attribute counts in attrCounts.
FPTree(LongArrayList attrCountList, long minSupport)
          Creates an FPTree using the attribute counts in attrCountList.
 
Method Summary
 void accumulate(IntArrayList argItems, long count)
          Adds an itemset with the given occurrance count.
 void accumulate(List<Integer> argItems, long count)
          Adds an itemset with the given occurrance count.
 Iterable<Integer> attrIterableRev()
          Returns an Iterable over the attributes in the tree, sorted by frequency (high to low).
 FPTree createMoreFreqConditionalTree(int targetAttr)
          Returns a conditional FP tree based on the targetAttr, containing only items that are more frequent.
 long headerCount(int attribute)
          Returns the count of the given attribute, as supplied on construction.
 FPTree.FPNode root()
          Returns the root node of the tree.
 Pair<FPTree,FPTree> splitSinglePrefix()
          Return a pair of trees that result from separating a common prefix (if one exists) from the lower portion of this tree.
 String toString()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

FPTree

public FPTree(LongArrayList attrCountList,
              long minSupport)
Creates an FPTree using the attribute counts in attrCountList. Note that the counts in attrCountList are assumed to be complete; they are not updated as the tree is modified.


FPTree

public FPTree(long[] attrCounts,
              long minSupport)
Creates an FPTree using the attribute counts in attrCounts. Note that the counts in attrCounts are assumed to be complete; they are not updated as the tree is modified.

Method Detail

headerCount

public long headerCount(int attribute)
Returns the count of the given attribute, as supplied on construction.


root

public FPTree.FPNode root()
Returns the root node of the tree.


accumulate

public void accumulate(IntArrayList argItems,
                       long count)
Adds an itemset with the given occurrance count.


accumulate

public void accumulate(List<Integer> argItems,
                       long count)
Adds an itemset with the given occurrance count.


attrIterableRev

public Iterable<Integer> attrIterableRev()
Returns an Iterable over the attributes in the tree, sorted by frequency (high to low).


createMoreFreqConditionalTree

public FPTree createMoreFreqConditionalTree(int targetAttr)
Returns a conditional FP tree based on the targetAttr, containing only items that are more frequent.


splitSinglePrefix

public Pair<FPTree,FPTree> splitSinglePrefix()
Return a pair of trees that result from separating a common prefix (if one exists) from the lower portion of this tree.


toString

public String toString()
Overrides:
toString in class Object


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