protected override Itemset[] ScanDbAndCountCandidatesSupport(Itemset[] candidates)
{
if (candidates.Length == 0)
{
return(candidates);
}
Dictionary <UInt32[], Itemset> candidatesDictionary = CreateCandidatesDictionary(candidates);
foreach (var transaction in _db.Transactions)
{
List <UInt32[]> transactionsSubItemsets = ItemsetHelper.GenerateSubItemsets(transaction.Items, candidates[0].Length);
for (int i = 0; i < transactionsSubItemsets.Count; i++)
{
Itemset itemset;
if (candidatesDictionary.TryGetValue(transactionsSubItemsets[i], out itemset))
{
itemset.Support++;
}
}
}
return(candidates);
}
public void Can_Generate_All_3_Length_SubItemsets()
{
Itemset itemset = new Itemset(new uint[] { 1, 2, 3, 5, 6 });
var result = ItemsetHelper.GenerateSubItemsets(itemset.Items, 3);
Assert.AreEqual(10, result.Count);
// Length
Assert.AreEqual(3, result[0].Length);
Assert.AreEqual(3, result[9].Length);
// SubItemsets
Assert.AreEqual(result[0][0], 1);
Assert.AreEqual(result[0][1], 2);
Assert.AreEqual(result[0][2], 3);
Assert.AreEqual(result[9][0], 3);
Assert.AreEqual(result[9][1], 5);
Assert.AreEqual(result[9][2], 6);
}
