به صورت زیر استفاده کنید.
Ptr<ml::KNearest> knn(ml::KNearest::create());
Mat_<float> train_features(6,4);
train_features << 2,2,2,2,
3,3,3,3,
4,4,4,4,
5,5,5,5,
6,6,6,6,
7,7,7,7;
Mat_<int> train_labels(1,6);
train_labels << 2,3,4,5,6,7;
knn->train(train_features, ml::ROW_SAMPLE, train_labels);
Mat_<float> test_feature(1,4);
test_feature<< 3,3,3,3;
int K=3;
Mat response,dist;
knn->findNearest(test_feature, K, noArray(), response, dist);
cout << response << endl;
cout << dist<< endl;