|  |  | 
|  | /** | 
|  | * Elastic net regulation for linear regression using FISTA optimizer | 
|  | */ | 
|  |  | 
|  | /** | 
|  | * @brief Linear regression (incremental gradient): Transition function | 
|  | */ | 
|  | DECLARE_UDF(elastic_net, gaussian_fista_transition) | 
|  |  | 
|  | /** | 
|  | * @brief Linear regression (incremental gradient): State merge function | 
|  | */ | 
|  | DECLARE_UDF(elastic_net, gaussian_fista_merge) | 
|  |  | 
|  | /** | 
|  | * @brief Linear regression (incremental gradient): Final function | 
|  | */ | 
|  | DECLARE_UDF(elastic_net, gaussian_fista_final) | 
|  |  | 
|  | /** | 
|  | * @brief Linear regression (incremental gradient): Difference in | 
|  | *     log-likelihood between two transition states | 
|  | */ | 
|  | DECLARE_UDF(elastic_net, __gaussian_fista_state_diff) | 
|  |  | 
|  | /** | 
|  | * @brief Linear regression (incremental gradient): Convert | 
|  | *     transition state to result tuple | 
|  | */ | 
|  | DECLARE_UDF(elastic_net, __gaussian_fista_result) | 
|  |  | 
|  | // /** | 
|  | //  * @brief (incremental gradient): Prediction | 
|  | //  */ | 
|  | // DECLARE_UDF(elastic_net, gaussian_igd_predict) |