private void AddTransactionNodes(Transaction transaction)
{
FPTreeNode actualNode = _rootNode;
var transactionItems = GetTransactionItems(transaction);
for (int i = 0; i < transactionItems.Length; i++)
{
// Because we order transaction's items by support,
// we can break loop when we find the first non-frequent item in transaction.
if (!IsFrequent(transactionItems[i]))
{
break;
}
FPTreeNode subNode;
if (actualNode.TryGetSubNode(transactionItems[i], out subNode))
{
subNode.Support++;
actualNode = subNode;
}
else
{
AddSubNodesForTransactionItems(actualNode, transactionItems, i);
break;
}
}
}
private FPTreeNode FindOrCreateNode(FPTreeNode actualTreeNode, out bool found)
{
FPTreeNode existingNode;
found = _visitedNodesMapping.TryGetValue(actualTreeNode, out existingNode);
return(found ? existingNode : new FPTreeNode(FPTreeNodeType.Node)
{
Item = actualTreeNode.Item
});
}
internal FPTreeNode AddSubNode(UInt32 item)
{
FPTreeNode subNode = new FPTreeNode
{
Support = 1,
Item = item,
Type = FPTreeNodeType.Node,
ParentNode = this
};
_subNodes.Add(item, subNode);
return(subNode);
}
private void AddSubNodesForTransactionItems(FPTreeNode parentNode, UInt32[] transaction, int transactionStartIndex)
{
FPTreeNode actualNode = parentNode;
for (int i = transactionStartIndex; i < transaction.Length; i++)
{
actualNode = actualNode.AddSubNode(transaction[i]);
_header.Add(actualNode);
}
// Last item is on leaf node, save it.
_leafNodes.Add(actualNode);
}
public FPTreePrefixPathItem Add(FPTreeNode node)
{
FPTreePrefixPathItem item = new FPTreePrefixPathItem
{
FPTreeNode = node
};
List <FPTreePrefixPathItem> itemList;
if (!_items.TryGetValue(node.Item, out itemList))
{
itemList = new List <FPTreePrefixPathItem>();
_items.Add(node.Item, itemList);
}
itemList.Add(item);
return(item);
}
internal void AddTransaction(FPTreeNode fPTreeNode, Int32 support)
{
if (fPTreeNode.Type == FPTreeNodeType.Root)
{
return;
}
FPTreeNode curretNodeInConditioanlTree = null;
FPTreeNode currentNodeInInputFpTree = fPTreeNode;
// We are navigatin from botton to up in origin transaction and creating a new one.
while (currentNodeInInputFpTree.Type != FPTreeNodeType.Root)
{
bool existingNode;
FPTreeNode node = FindOrCreateNode(currentNodeInInputFpTree, out existingNode);
node.Support += support;
if (curretNodeInConditioanlTree != null)
{
curretNodeInConditioanlTree.ParentNode = node;
}
if (!existingNode)
{
_visitedNodesMapping.Add(currentNodeInInputFpTree, node);
_header.Add(node);
}
// TODO: When we have found already visited node, we can traverse it to up and just increment support.
// Move upward in tree traversing;
curretNodeInConditioanlTree = node;
currentNodeInInputFpTree = currentNodeInInputFpTree.ParentNode;
}
curretNodeInConditioanlTree.ParentNode = currentNodeInInputFpTree;
}
public bool TryGetSubNode(UInt32 item, out FPTreeNode subNode)
{
return(_subNodes.TryGetValue(item, out subNode));
}