public Apriori(double minSupport, double minConfidence, IEnumerable <IAprioriData <T> > datas)
{
_minSupport = minSupport;
_minConfidence = minConfidence;
_datas = new List <IEnumerable <T> >();
_setDatas = new List <SetData <T> >();
_supportTable = new Dictionary <T, double>();
var itemHashset = new HashSet <T>();
foreach (var data in datas)
{
var list = data.GetData();
_datas.Add(list);
foreach (T item in list)
{
itemHashset.Add(item);
}
}
foreach (T item in itemHashset)
{
SetData <T> set = new SetData <T>();
set.Set.Add(item);
if (CheckSupport(set))
{
_setDatas.Add(set);
}
_supportTable.Add(item, set.Support);
}
}
private bool CheckSupport(SetData <T> setData)
{
var set = setData.FullSet;
double count = 0;
foreach (var data in _datas)
{
if (data.Intersect(set).Count() == set.Count())
{
count++;
}
}
setData.Support = count / _datas.Count;
return(setData.Support >= _minSupport);
}
public void Train()
{
Show();
List <SetData <T> > newSetDatas = new List <SetData <T> >();
Dictionary <IEnumerable <T>, T> exist = new Dictionary <IEnumerable <T>, T>();
for (int i = 0; i < _setDatas.Count; i++)
{
for (int j = 0; j < _setDatas.Count; j++)
{
if (i == j)
{
continue;
}
var fullSetI = _setDatas[i].FullSet;
var fullSetJ = _setDatas[j].FullSet;
var union = fullSetI.Union(fullSetJ);
if (union.Count() == fullSetI.Count() + 1)
{
var select = union.Except(fullSetI).ElementAt(0);
bool hasSameSet = false;
foreach (var v in exist)
{
if (v.Key.Except(fullSetI).Count() == 0 &&
select.Equals(v.Value))
{
hasSameSet = true;
break;
}
}
if (hasSameSet)
{
continue;
}
SetData <T> set = new SetData <T>();
set.Set = new HashSet <T>(fullSetI);
set.Select = select;
set.Confidence = _setDatas[i].Support;
if (CheckSupport(set) &&
CheckConfidence(set))
{
set.Lift = set.Confidence / _supportTable[select];
newSetDatas.Add(set);
exist.Add(fullSetI, select);
}
}
}
}
if (newSetDatas.Count > 0)
{
_setDatas = newSetDatas;
Train();
}
}
private bool CheckConfidence(SetData <T> setData)
{
setData.Confidence = setData.Support / setData.Confidence;
return(setData.Confidence >= _minConfidence);
}