public Itemset Remove(Itemset itemset)
{
Itemset removed = new Itemset();
removed.AddRange(from item in this
where !itemset.Contains(item)
select item);
return(removed);
}
public static ItemsetCollection DoAprioriNew(ItemsetCollection db, double supportThreshold)
{
//Itemset I = db.GetUniqueItems();
ItemsetCollection Fre = new ItemsetCollection(); //List of Items > support
ItemsetCollection L = new ItemsetCollection(); //resultant large itemsets
ItemsetCollection T = new ItemsetCollection(); //frequent items
//item > support
Itemset I = db.GetUniqueItems();
foreach (int item in I)
{
Itemset itemset = new Itemset()
{
item
};
itemset.Support = db.FindSupport(itemset);
if (itemset.Support >= supportThreshold)
{
Fre.Add(itemset);
}
}
ItemsetCollection subsets = Bit.FindSubsets(Fre.GetUniqueItems(), 0); //get all subsets
//Dictionary<Itemset, int> subsetsDic = subsets.Select((x, i) => new {x = x, i = 0 }).ToDictionary(k => k.x,k=>k.i);
//frequent items
foreach (Itemset itemdata in db)
{
Itemset itemset = new Itemset();
foreach (Itemset itemFre in Fre)
{
if (itemdata.Contains(itemFre[0]))
{
itemset.Add(itemFre[0]);
}
}
if (itemset.Count > 0)
{
T.Add(itemset);
foreach (Itemset items in subsets)
{
if (itemset.Contains(items))
{
items.Support++;
}
}
}
}
foreach (Itemset items in subsets)
{
if (items.Count > 0)
{
items.Support = (items.Support / (double)db.Count) * 100.0;
if (items.Support >= supportThreshold)
{
L.Add(items);
}
}
}
return(L);
}