PoseBetweenFactor.h

/* ----------------------------------------------------------------------------
 
 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)
 
 * See LICENSE for the license information
 
 * -------------------------------------------------------------------------- */

#pragma once
 
#include <ostream>
 
#include <gtsam/nonlinear/NonlinearFactor.h>
#include <gtsam/nonlinear/NoiseModelFactorN.h>
#include <gtsam/geometry/concepts.h>
#include <gtsam/base/Testable.h>
 
namespace gtsam {

  template<class POSE>
  class PoseBetweenFactor
      : public NoiseModelFactorT<typename traits<POSE>::TangentVector, POSE,
                                 POSE> {
 
  private:
 
    typedef PoseBetweenFactor<POSE> This;
    typedef NoiseModelFactorT<typename traits<POSE>::TangentVector, POSE, POSE>
        Base;
    using ErrorVector = typename traits<POSE>::TangentVector;
 
    POSE measured_; 
    std::optional<POSE> body_P_sensor_; 

    GTSAM_CONCEPT_TESTABLE_TYPE(POSE)
    GTSAM_CONCEPT_POSE_TYPE(POSE)
  public:
 
    // Provide access to the Matrix& version of evaluateError:
    using Base::evaluateError;
 
    // shorthand for a smart pointer to a factor
    typedef typename std::shared_ptr<PoseBetweenFactor> shared_ptr;

    PoseBetweenFactor() {}

    PoseBetweenFactor(Key key1, Key key2, const POSE& measured,
        const SharedNoiseModel& model, std::optional<POSE> body_P_sensor = {}) :
      Base(model, key1, key2), measured_(measured), body_P_sensor_(body_P_sensor) {
    }
 
    ~PoseBetweenFactor() override {}

    gtsam::NonlinearFactor::shared_ptr clone() const override {
      return std::static_pointer_cast<gtsam::NonlinearFactor>(
          gtsam::NonlinearFactor::shared_ptr(new This(*this))); }


    void print(const std::string& s, const KeyFormatter& keyFormatter = DefaultKeyFormatter) const override {
      std::cout << s << "BetweenFactor("
          << keyFormatter(this->key1()) << ","
          << keyFormatter(this->key2()) << ")\n";
      measured_.print("  measured: ");
      if(this->body_P_sensor_)
        this->body_P_sensor_->print("  sensor pose in body frame: ");
      this->noiseModel_->print("  noise model: ");
    }

    bool equals(const NonlinearFactor& expected, double tol=1e-9) const override {
      const This *e =  dynamic_cast<const This*> (&expected);
      return e != nullptr
          && Base::equals(*e, tol)
          && this->measured_.equals(e->measured_, tol)
          && ((!body_P_sensor_ && !e->body_P_sensor_) || (body_P_sensor_ && e->body_P_sensor_ && body_P_sensor_->equals(*e->body_P_sensor_)));
    }


    ErrorVector evaluateError(const POSE& p1, const POSE& p2,
                              OptionalMatrixType H1,
                              OptionalMatrixType H2) const override {
      if(body_P_sensor_) {
        POSE hx;
        if(H1 || H2) {
          Matrix H3;
          hx = p1.compose(*body_P_sensor_,H3).between(p2.compose(*body_P_sensor_), H1, H2); // h(x)
          if(H1) (*H1) *= H3;
          if(H2) (*H2) *= H3;
        } else {
          hx = p1.compose(*body_P_sensor_).between(p2.compose(*body_P_sensor_)); // h(x)
        }
        // manifold equivalent of h(x)-z -> log(z,h(x))
        return measured_.localCoordinates(hx);
      } else {
        POSE hx = p1.between(p2, H1, H2); // h(x)
        // manifold equivalent of h(x)-z -> log(z,h(x))
        return measured_.localCoordinates(hx);
      }
    }

    const POSE& measured() const {
      return measured_;
    }
 
  private:
 
#if GTSAM_ENABLE_BOOST_SERIALIZATION
    friend class boost::serialization::access;
    template<class ARCHIVE>
    void serialize(ARCHIVE & ar, const unsigned int /*version*/) {
      ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base);
      ar & BOOST_SERIALIZATION_NVP(measured_);
 
    }
#endif
  }; // \class PoseBetweenFactor
 
}