RIU.h

#ifndef MTF_RIU_H
#define MTF_RIU_H

#include "AppearanceModel.h"

_MTF_BEGIN_NAMESPACE

struct RIUParams : AMParams{

    bool debug_mode;
    RIUParams(const AMParams *am_params,
         bool _debug_mode);
    RIUParams(const RIUParams *params = nullptr);
};

struct RIUDist : AMDist{
    typedef double ElementType;
    typedef double ResultType;
    RIUDist(const string &_name, const bool _dist_from_likelihood,
        const double _likelihood_alpha, const unsigned int _patch_size);
    double operator()(const double* a, const double* b,
        size_t size, double worst_dist = -1) const override;
private:
    const bool dist_from_likelihood;
    const double likelihood_alpha;
    const unsigned int patch_size;
};

class RIU : public AppearanceModel{
public:
    typedef RIUParams ParamType;
    typedef RIUDist DistType;

    RIU(const ParamType *riu_params = nullptr, const int _n_channels = 1);

    double getLikelihood() const override;

    bool isSymmetrical() const override{ return false; }

    //-------------------------------initialize functions------------------------------------//
    void initializeSimilarity() override;
    void initializeGrad() override;
    void initializeHess() override{}

    //-------------------------------update functions------------------------------------//
    void updateSimilarity(bool prereq_only = true) override;
    void updateInitGrad() override;
    void updateCurrGrad() override;

    //-------------------------------interfacing functions------------------------------------//
    void cmptInitHessian(MatrixXd &init_hessian, const MatrixXd &init_pix_jacobian) override;
    void cmptInitHessian(MatrixXd &init_hessian, const MatrixXd &init_pix_jacobian,
        const MatrixXd &init_pix_hessian) override;
    void cmptCurrHessian(MatrixXd &curr_hessian, const MatrixXd &curr_pix_jacobian) override;
    void cmptCurrHessian(MatrixXd &curr_hessian, const MatrixXd &curr_pix_jacobian,
        const MatrixXd &curr_pix_hessian) override;
        void cmptSelfHessian(MatrixXd &self_hessian, const MatrixXd &curr_pix_jacobian) override;
    void cmptSelfHessian(MatrixXd &self_hessian, const MatrixXd &curr_pix_jacobian,
        const MatrixXd &curr_pix_hessian) override;

    // -------------------- distance feature functions -------------------- //
    VectorXd curr_feat_vec;
    const DistType* getDistFunc() override{
        return new DistType(name, params.dist_from_likelihood, 
            params.likelihood_alpha, patch_size);
    }
    unsigned int getDistFeatSize() override{ return patch_size + 1; }
    void initializeDistFeat() override{
        curr_feat_vec.resize(patch_size + 1);
    }
    void updateDistFeat(double* feat_addr) override;
    const double* getDistFeat() override{ return curr_feat_vec.data(); }
    void updateDistFeat() override{     
        updateDistFeat(curr_feat_vec.data());
        curr_feat_vec[0] = 1;
    }

protected:
    ParamType params;

    double N_inv;
    VectorXd r;
    VectorXd r_cntr;
    VectorXd df_dr;
    VectorXd dr_dIt, dr_dI0;
    double r_mean, r_var;
    double r_mean_inv;
};

_MTF_END_NAMESPACE

#endif