Exemple #1
0
// Predict the label of an instance, given a model with probability
// information. This method returns the label of the predicted class,
// a map of class probabilities, and an error if the model was not
// trained without the required information to do probability estimates.
func (model *Model) PredictProbability(nodes []FeatureValue) (float64, map[int]float64, error) {
	if C.svm_check_probability_model_wrap(model.model) == 0 {
		return 0, nil, errors.New("Model was not trained to do probability estimates")
	}

	// Allocate sparse C feature vector.
	cn := cNodes(nodes)
	defer C.nodes_free(cn)

	// Allocate C array for probabilities.
	cProbs := C.probs_new(model.model)
	defer C.free(unsafe.Pointer(cProbs))

	r := C.svm_predict_probability_wrap(model.model, cn, cProbs)

	// Store the probabilities in a slice
	labels := model.labels()
	probs := make(map[int]float64)
	for idx, label := range labels {
		probs[label] = float64(C.get_double_idx(cProbs, C.int(idx)))
	}

	return float64(r), probs, nil
}
Exemple #2
0
func newProbs(model *C.model_t) *C.double {
	probs := tryNew(func() unsafe.Pointer {
		return unsafe.Pointer(C.probs_new(model))
	})
	return (*C.double)(probs)
}