Struct oozie::recommender::BasicItemRecommender

pub struct BasicItemRecommender<'a, D: DataHandler + 'a> { /* fields omitted */ }

An item based threshold neighbors recommender

Methods

impl<'a, D: DataHandler + 'a> BasicItemRecommender<'a, D>

fn new(
    data_handler: &mut D,
    threshold: f64,
    similarity: fn(_: &HashMap<usize, f64>, _: &HashMap<usize, f64>, _: usize) -> f64
) -> BasicItemRecommender<D>

Initializes a new recommender from a data handler, computes and stores the similarities between items

fn add_user(&mut self, user_id: ID) -> bool

Adds an user to the data handler

fn add_item(&mut self, item_id: ID) -> bool

Adds an item to the data handler

fn add_rating(&mut self, user_id: ID, item_id: ID, rating: f64) -> bool

Adds a rating to the data handler, it computes the similarities for the item which had a new rating

Trait Implementations

impl<'a, D: DataHandler + 'a> Recommender for BasicItemRecommender<'a, D>

fn predict(&self, user_id: ID, item_id: ID) -> f64

Predicts the rating for an user and item averaging the ratings of the items whose similarities with the item are above the threshold. If there are no item above the threshold it returns -1.0

fn recommend(&self, user_id: ID) -> Vec<(ID, f64)>

Generates a sorted vector of item IDs by a predicted rating which is computed in the same way that the predict method. It ignores items that have a predicted rating of -1.0