public int CreateFPTreeAndGenerateFrequentItemsets(
IInputDatabaseHelper _inputHelper, IOutputDatabaseHelper _outHelper, float minSup)
{
outputDatabaseHelper = _outHelper;
var watch = System.Diagnostics.Stopwatch.StartNew();
FPTree _fpTree = new FPTree(_inputHelper, minSup);
fpTree = _fpTree;
int totalFrequentItemSets = GenerateFrequentItemSets();
watch.Stop();
outputDatabaseHelper.WriteAggregatedResult(minSup, totalFrequentItemSets, (double)watch.ElapsedMilliseconds);
return(totalFrequentItemSets);
}
private int Mine(FPTree fpTree, ItemSet anItemSet)
{
int minedItemSets = 0;
FPTree projectedTree;
projectedTree = fpTree.Project(anItemSet.GetLastItem());
minedItemSets = projectedTree.FrequentItems.Count;
foreach (Item anItem in projectedTree.FrequentItems)
{
ItemSet nextItemSet = anItemSet.Clone();
nextItemSet.AddItem(anItem);
minedItemSets += Mine(projectedTree, nextItemSet);
}
return(minedItemSets);
}
public FPTree Project(Item anItem)
{
FPTree tree = new FPTree();
tree.minimumSupport = minimumSupport;
tree.minimumSupportCount = minimumSupportCount;
Node startNode = headerTable[anItem.Symbol];
while (startNode != null)
{
int projectedFPCount = startNode.FpCount;
Node tempNode = startNode;
List <Node> aBranch = new List <Node>();
while (null != tempNode.Parent)
{
Node parentNode = tempNode.Parent;
if (parentNode.IsNull())
{
break;
}
Node newNode = new Node(parentNode.Symbol);
//newNode.Parent = parentNode.Parent;
newNode.FpCount = projectedFPCount;
aBranch.Add(newNode);
tempNode = tempNode.Parent;
}
aBranch.Reverse();
tree.InsertBranch(aBranch);
startNode = startNode.NextHeader;
}
//prune infrequents
/*foreach(KeyValuePair<string,Node> hEntry in tree.headerTable)
* {
* int c = tree.GetTotalSupportCount(hEntry.Value.Symbol);
* if(c < minimumSupportCount)
* {
* tree.headerTable.Remove(hEntry);
* }
* }*/
IDictionary <string, Node> inFrequentHeaderTable = tree.headerTable.
Where(x => tree.GetTotalSupportCount(x.Value.Symbol) < minimumSupportCount).
ToDictionary(p => p.Key, p => p.Value);
tree.headerTable = tree.headerTable.
Where(x => tree.GetTotalSupportCount(x.Value.Symbol) >= minimumSupportCount).
ToDictionary(p => p.Key, p => p.Value);
foreach (KeyValuePair <string, Node> hEntry in inFrequentHeaderTable)
{
Node temp = hEntry.Value;
while (null != temp)
{
Node tempNext = temp.NextHeader;
Node tempParent = temp.Parent;
tempParent.Children.Remove(temp);
temp = tempNext;
}
}
tree.frequentItems = frequentItems.FindAll
(
delegate(Item item)
{
return(tree.headerTable.ContainsKey(item.Symbol));
}
);
return(tree);
}
public FPGrowth(FPTree tree, IOutputDatabaseHelper outDatabaseHelper)
: this()
{
fpTree = tree;
outputDatabaseHelper = outDatabaseHelper;
}
public FPGrowth()
{
fpTree = null;
outputDatabaseHelper = null;
}
