Source code for cornac.models.ibpr.recom_ibpr

# -*- coding: utf-8 -*-
@author: Dung D. Le (Andrew) <>

import numpy as np
from .ibpr import *
from ..recommender import Recommender
from ...exception import ScoreException

[docs]class IBPR(Recommender): """Indexable Bayesian Personalized Ranking. Parameters ---------- k: int, optional, default: 20 The dimension of the latent factors. max_iter: int, optional, default: 100 Maximum number of iterations or the number of epochs for SGD. learning_rate: float, optional, default: 0.05 The learning rate for SGD. lamda: float, optional, default: 0.001 The regularization parameter. batch_size: int, optional, default: 100 The batch size for SGD. name: string, optional, default: 'IBRP' The name of the recommender model. trainable: boolean, optional, default: True When False, the model is not trained and Cornac assumes that the model already \ pre-trained (U and V are not None). verbose: boolean, optional, default: False When True, some running logs are displayed. init_params: dictionary, optional, default: None List of initial parameters, e.g., init_params = {'U':U, 'V':V} \ please see below the definition of U and V. U: csc_matrix, shape (n_users,k) The user latent factors, optional initialization via init_params. V: csc_matrix, shape (n_items,k) The item latent factors, optional initialization via init_params. References ---------- * Le, D. D., & Lauw, H. W. (2017, November). Indexable Bayesian personalized ranking for efficient top-k recommendation.\ In Proceedings of the 2017 ACM on Conference on Information and Knowledge Management (pp. 1389-1398). ACM. """ def __init__(self, k=20, max_iter=100, learning_rate = 0.05, lamda = 0.001, batch_size = 100, name="ibpr", trainable = True, verbose=False, init_params = None): Recommender.__init__(self, name=name, trainable=trainable, verbose=verbose) self.k = k self.init_params = init_params self.max_iter = max_iter = name self.learning_rate = learning_rate self.lamda = lamda self.batch_size = batch_size self.U = init_params['U'] # matrix of user factors self.V = init_params['V'] # matrix of item factors # fit the recommender model to the traning data
[docs] def fit(self, train_set): """Fit the model to observations. Parameters ---------- train_set: object of type TrainSet, required An object contraining the user-item preference in csr scipy sparse format,\ as well as some useful attributes such as mappings to the original user/item ids.\ Please refer to the class TrainSet in the "data" module for details. """, train_set) X = self.train_set.matrix #change the data to original user Id item Id and rating format cooX = X.tocoo() data = np.ndarray(shape=(len(, 3), dtype=float) data[:, 0] = cooX.row data[:, 1] = cooX.col data[:, 2] = if self.verbose: print('Learning...') res = ibpr(X, data, k=self.k, n_epochs=self.max_iter,lamda = self.lamda, learning_rate= self.learning_rate, batch_size = self.batch_size, init_params=self.init_params) self.U = np.asarray(res['U']) self.V = np.asarray(res['V']) if self.verbose: print('Learning completed')
[docs] def score(self, user_id, item_id): """Predict the scores/ratings of a user for a list of items. Parameters ---------- user_id: int, required The index of the user for whom to perform score predictions. item_id: int, required The index of the item to be scored by the user. Returns ------- A scalar The estimated score (e.g., rating) for the user and item of interest """ if self.train_set.is_unk_user(user_id) or self.train_set.is_unk_item(item_id): raise ScoreException("Can't make score prediction for (user_id=%d, item_id=%d)" % (user_id, item_id)) user_pred = self.V[item_id, :].dot(self.U[user_id, :]) return user_pred
[docs] def rank(self, user_id, candidate_item_ids=None): """Rank all test items for a given user. Parameters ---------- user_id: int, required The index of the user for whom to perform item raking. candidate_item_ids: 1d array, optional, default: None A list of item indices to be ranked by the user. If `None`, list of ranked known item indices will be returned Returns ------- Numpy 1d array Array of item indices sorted (in decreasing order) relative to some user preference scores. """ if self.train_set.is_unk_user(user_id): if candidate_item_ids is None: return np.arange(self.train_set.num_items) return candidate_item_ids known_item_scores =[user_id, :]) if candidate_item_ids is None: ranked_item_ids = known_item_scores.argsort()[::-1] return ranked_item_ids else: num_items = max(self.train_set.num_items, max(candidate_item_ids) + 1) user_pref_scores = np.ones(num_items) * self.default_score() user_pref_scores[:self.train_set.num_items] = known_item_scores ranked_item_ids = user_pref_scores.argsort()[::-1] mask = np.in1d(ranked_item_ids, candidate_item_ids) ranked_item_ids = ranked_item_ids[mask] return ranked_item_ids