double j=example.getValue(tu);
int uid=(int) j;
j=example.getValue(ti);
int iid=(int) j;
test_data.Add(user_mapping.ToInternalID(uid), item_mapping.ToInternalID(iid));
}
Map<String,Double> result= ItemPredictionEval.Evaluate(model, test_data,train_data,test_data.GetAllUsers(),train_data.GetAllItems()); //train_data.GetAllUsers(),train_data.GetAllItems()