public static ItemsetCollection FindSubsets(Itemset itemset, int n)
{
ItemsetCollection subsets = new ItemsetCollection();
int subsetCount = (int)Math.Pow(2, itemset.Count);
for (int i = 0; i < subsetCount; i++)
{
if (n == 0 || GetOnCount(i, itemset.Count) == n)
{
string binary = DecimalToBinary(i, itemset.Count);
Itemset subset = new Itemset();
for (int charIndex = 0; charIndex < binary.Length; charIndex++)
{
if (binary[charIndex] == '1')
{
subset.Add(itemset[charIndex]);
}
}
subsets.Add(subset);
}
}
return(subsets);
}
static ItemsetCollection AprioriCalc(ItemsetCollection db, double supportThreshold)
{
Itemset I = db.GetUniqueItems();
ItemsetCollection LitemList = new ItemsetCollection();
ItemsetCollection PitemList = new ItemsetCollection();
foreach (string item in I)
{
PitemList.Add(new Itemset()
{
item
});
}
int k = 2;
while (PitemList.Count != 0)
{
LitemList.Clear();
foreach (Itemset index in PitemList)
{
index.Support = db.FindSupport(index);
if (index.Support >= supportThreshold)
{
LitemList.Add(index);
itemList.Add(index);
}
}
PitemList.Clear();
PitemList.AddRange(Bit.FindSubsets(LitemList.GetUniqueItems(), k)); //get k-item subsets
k += 1;
}
return(itemList);
}
public ItemsetCollection setData()
{
_items = new Itemset();
_items.Add("Game");
_items.Add("Water");
_items.Add("Monster");
_items.Add("Candy");
_items.Add("Shoes");
_items.Add("Controller");
_items.Add("PizzaRolls");
_items.Add("Console");
_db = new ItemsetCollection();
_db.Add(new Itemset()
{
_items[0], _items[2], _items[3], _items[5]
});
_db.Add(new Itemset()
{
_items[1], _items[4]
});
_db.Add(new Itemset()
{
_items[0], _items[2], _items[6]
});
_db.Add(new Itemset()
{
_items[1], _items[3], _items[4], _items[7]
});
_db.Add(new Itemset()
{
_items[0], _items[1], _items[6]
});
return(_db);
}