How to add a new Predictor in Prediction module

Introduction

The Predictor generates the predicted trajectory for each obstacle. Here, let's assume we want to add a new predictor to our vehicle, for other types of obstacles, the procedure is very as follows:

1. Define a class that inherits Predictor
2. Implement the class NewPredictor
3. Add a new predictor type in proto prediction_conf.proto
4. Update prediction_conf
5. Upate the Predictor manager

Steps to add a new predictor

The following steps will add a Predictor NewPredictor.

Define a class that inherits Predictor

Create a new file named new_predictor.h in the folder modules/prediction/predictor/vehicle and define it as follows:

#include "modules/prediction/predictor/predictor.h"

namespace apollo {
namespace prediction {

class NewPredictor : public Predictor {
 public:
  void Predict(Obstacle* obstacle) override;
  // Other useful functions and fields.
};

}  // namespace prediction
}  // namespace apollo

Implement the class NewPredictor

Create a new file named new_predictor.cc in the same folder of new_predictor.h. Implement it like this:

#include "modules/prediction/predictor/vehicle/new_predictor.h"

namespace apollo {
namespace prediction {

NewPredictor::Predict(Obstacle* obstacle)() {
  // Get the results from evaluator
  // Generate the predicted trajectory
}

// Other functions

}  // namespace prediction
}  // namespace apollo

Add a new predictor type in proto prediction_conf.proto

  enum PredictorType {
    LANE_SEQUENCE_PREDICTOR = 0;
    FREE_MOVE_PREDICTOR = 1;
    REGIONAL_PREDICTOR = 2;
    MOVE_SEQUENCE_PREDICTOR = 3;
    NEW_PREDICTOR = 4;
  }

Update prediction_conf

In the file modules/prediction/conf/prediction_conf.pb.txt, update the field predictor_type like this:

obstacle_conf {
  obstacle_type: VEHICLE
  obstacle_status: ON_LANE
  evaluator_type: NEW_EVALUATOR
  predictor_type: NEW_PREDICTOR
}

Upate Predictor manager

Update CreateEvluator( ... ) like this:

  case ObstacleConf::NEW_PREDICTOR: {
      predictor_ptr.reset(new NewPredictor());
      break;
    }

Update RegisterPredictors() like this:

  RegisterPredictor(ObstacleConf::NEW_PREDICTOR);

After completing the steps above, you would have created a new Predictor.