}//end print
private void fpgrowth(FPTree tree, string[] prefixAlpha, int prefixSupport, Dictionary <string, int> mapSupport)
{
if (tree.hasMoreThanOnePath)
{
fpgrowthMoreThanOnePath(tree, prefixAlpha, prefixSupport, mapSupport);
}
else
{
addAllCombinationsForPathAndPrefix(tree.root.children.ElementAt(0), prefixAlpha);
}
}//end fpgrowth
public void Process()
{
itemsetCount = 0;
Dictionary <string, int> mapSupport = new Dictionary <string, int>();
scanDatabaseToDetermineFrequencyOfSingleItems(mapSupport);
_relativeMinSupport = (int)Math.Ceiling(_minSupport * transactionCount);
FPTree globaltree = new FPTree();
if (File.Exists(this.InputDataFile))
{
using (FileStream fs = new FileStream(this.InputDataFile, FileMode.Open, FileAccess.Read))
{
using (StreamReader sr = new StreamReader(fs))
{
string line = string.Empty;
while (!sr.EndOfStream)
{
line = sr.ReadLine();
if (line == string.Empty || line.Substring(0, 1) == "#" || line.Substring(0, 1) == "%" || line.Substring(0, 1) == "@")
{
continue;
}
//#### Need to add a delimiter variable
string[] lineSplited = line.Split(new char[] { ' ' });
List <string> transaction = new List <string>();
foreach (string item in lineSplited)
{
if (mapSupport[item] >= _relativeMinSupport)
{
transaction.Add(item);
}
}
transaction.Sort(new FPStringComparer(mapSupport));
globaltree.addTransaction(transaction);
}
}
}
globaltree.createHeaderList(mapSupport);
string[] prefixAlpha = new string[0];
fpgrowth(globaltree, prefixAlpha, transactionCount, mapSupport);
print(globaltree.root, " ");
}
else
{
//throw error that file does not exists
}
}//end Process
}//end Process
private void fpgrowthMoreThanOnePath(FPTree tree, string[] prefixAlpha, int prefixSupport, Dictionary <string, int> mapSupport)
{
//process the frequent items in reverse
for (int i = tree.headerList.Count - 1; i >= 0; i--)
{
string item = tree.headerList.ElementAt(i);
int support = mapSupport[item];
// if the item is not frequent, we skip it
if (support < _relativeMinSupport)
{
continue;
}
//Create the BETA by using concatentation of the Alpha with the current item
string[] beta = new string[prefixAlpha.Length + 1];
prefixAlpha.CopyTo(beta, 0);
beta[prefixAlpha.Length] = item;
int betaSupport = (prefixSupport < support) ? prefixSupport : support;
//Write out to file
writeItemsetToOutput(beta, betaSupport);
List <List <FPNode> > prefixPaths = new List <List <FPNode> >();
FPNode path = null;
if (tree.mapItemNodes.ContainsKey(item))
{
path = tree.mapItemNodes[item];
}
while (path != null)
{
// if the path is not just the root node
if (path.parent.itemID != null)
{
//build prefixpath
List <FPNode> prefixPath = new List <FPNode>();
// add this node.
prefixPath.Add(path);
//Recursively add all the parents of this node.
FPNode parent = path.parent;
while (parent.itemID != null)
{
prefixPath.Add(parent);
parent = parent.parent;
}
// add the path to the list of prefixpaths
prefixPaths.Add(prefixPath);
}
// We will look for the next prefixpath
path = path.nodeLink;
}
// (A) Calculate the frequency of each item in the prefixpath
Dictionary <string, int> mapSupportBeta = new Dictionary <string, int>();
// for each prefixpath
foreach (List <FPNode> prefixPath in prefixPaths)
{
// the support of the prefixpath is the support of its first node.
int pathCount = prefixPath.ElementAt(0).counter;
// for each node in the prefixpath,
// except the first one, we count the frequency
for (int j = 1; j < prefixPath.Count; j++)
{
FPNode node = prefixPath.ElementAt(j);
// if the first time we see that node id
if (!mapSupportBeta.ContainsKey(node.itemID))
{
// just add the path count
mapSupportBeta.Add(node.itemID, pathCount);
}
else
{
// otherwise, make the sum with the value already stored
mapSupportBeta[node.itemID] += pathCount;
}
}
}
// (B) Construct beta's conditional FP-Tree
FPTree treeBeta = new FPTree();
// add each prefixpath in the FP-tree
foreach (List <FPNode> prefixPath in prefixPaths)
{
treeBeta.addPrefixPath(prefixPath, mapSupportBeta, _relativeMinSupport);
}
// Create the header list.
treeBeta.createHeaderList(mapSupportBeta);
// Mine recursively the Beta tree if the root as child(s)
if (treeBeta.root.children.Count > 0)
{
// recursive call
fpgrowth(treeBeta, beta, betaSupport, mapSupportBeta);
}
}
}//end fpgrowthMoreThanOnePath
