static List<DataItem> LoadData(int classLabel, string type, int numTopics)
{
MongoServer server = MongoServer.Create();
MongoDatabase db = server.GetDatabase("docmodel");
MongoCollection<BsonDocument> coll = db.GetCollection<BsonDocument>("ldamodel_" + type + "_" + classLabel + "_" + numTopics);
MongoCursor<BsonDocument> cursor = coll.FindAll();
List<DataItem> items = new List<DataItem>();
foreach (BsonDocument doc in cursor)
{
DataItem item = new DataItem();
items.Add(item);
item.DataItemId = doc["DocID"].AsString;
if (!doc["ClassLabels"].IsBsonNull)
{
foreach (BsonValue cl in doc["ClassLabels"].AsBsonArray)
{
item.AddClassLabel(cl.AsInt32);
}
}
if (!doc["WordCounts"].IsBsonNull)
{
foreach (BsonDocument kvp in doc["WordCounts"].AsBsonArray)
{
foreach (BsonElement e in kvp)
{
item.AddItem(e.Value.AsInt32, 1);
}
}
}
item.Normalize();
}
cursor = null;
coll = null;
db = null;
server.Disconnect();
return items;
}
public double Func(DataItem item, double[] theta)
{
double sum = 0;
for (int j = 0; j < theta.Length; j++)
{
if (j == theta.Length - 1)
{
sum += theta[j];
}
else
{
sum += item.GetItemWeight(j) * theta[j];
}
}
double func = 1.0 / (1.0 + Math.Exp(-sum));
return func;
}
static void Test()
{
LogisticReg regression = new LogisticReg(2, 1, 1);
List<DataItem> items = new List<DataItem>();
StreamReader reader = new StreamReader(new FileStream("ex2data2.txt", FileMode.Open));
string line;
while ((line = reader.ReadLine()) != null)
{
string[] ss = line.Split(',');
DataItem item = new DataItem();
item.AddItem(0, double.Parse(ss[0]));
item.AddItem(1, double.Parse(ss[1]));
item.AddClassLabel(int.Parse(ss[2]));
items.Add(item);
}
double[] theta = { 0, 0 };
double r = regression.CostFunc(items, theta);
}