{

AR(corpus* corp, int K, double lambda, double biasReg)

: model(corp)

, K(K)

, lambda(lambda)

, biasReg(biasReg) {}

~AR() {}

void init();

void cleanUp();

double prediction(int user, int item);

void getParametersFromVector(double* g, double** beta_user, double*** gamma_user, double*** gamma_item, action_t action);

int sampleItem();

void train(int iterations, double learn_rate);

virtual void oneiteration(double learn_rate);

virtual void updateFactors(int item_id, int pos_user_id, int neg_user_id, double learn_rate);

string toString();

/* auxiliary variables */

double * beta_user;

double ** gamma_user;

double ** gamma_item;

/* hyper-parameters */

int K;

double lambda;

double biasReg;