Source code for cornac.models.hft.recom_hft

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#     http://www.apache.org/licenses/LICENSE-2.0
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import numpy as np

from ..recommender import Recommender
from ...exception import ScoreException


[docs]class HFT(Recommender): """Collaborative Topic Regression Parameters ---------- name: string, default: 'HFT' The name of the recommender model. k: int, optional, default: 10 The dimension of the latent factors. max_iter: int, optional, default: 50 Maximum number of iterations for EM step grad_iter: int, optional, default: 50 Maximum number of iterations for l-bfgs init_params: dictionary, optional, default: None List of initial parameters, e.g., init_params = {'alpha':alpha,'beta_u':beta_u,'beta_i':beta_i, 'gamma_u':gamma_u, 'gamma_v':gamma_v} alpha: float Model offset, optional initialization via init_params. beta_u: ndarray. shape (n_user, 1) User biases, optional initialization via init_params. beta_u: ndarray. shape (n_item, 1) Item biases, optional initialization via init_params. gamma_u: ndarray, shape (n_users,k) The user latent factors, optional initialization via init_params. gamma_v: ndarray, shape (n_items,k) The item latent factors, optional initialization via init_params. lambda_text: float, default : 0.1 Weight of likelihood in loss function l2_reg: float, default : 0.001 Regularization for user item latent factor vocab_size: int, optional, default: 8000 Vocab size for auxiliary text data seed: int, optional, default: None Random seed for weight initialization. trainable: boolean, optional, default: True When False, the model is not trained and Cornac assumes that the model already pre-trained (gamma_u and gamma_v are not None). References ---------- Julian McAuley, Jure Leskovec. "Hidden Factors and Hidden Topics: Understanding Rating Dimensions with Review Text" RecSys '13 Proceedings of the 7th ACM conference on Recommender systems Pages 165-172 """ def __init__(self, name='HFT', k=10, lambda_text=0.1, l2_reg=0.001, vocab_size=8000, max_iter=50, grad_iter=50, trainable=True, verbose=True, init_params=None, seed=None): super().__init__(name=name, trainable=trainable, verbose=verbose) self.k = k self.lambda_text = lambda_text self.l2_reg = l2_reg self.grad_iter = grad_iter self.name = name self.max_iter = max_iter self.verbose = verbose self.init_params = {} if not init_params else init_params self.seed = seed self.vocab_size = vocab_size
[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. """ Recommender.fit(self, train_set) from ...utils.init_utils import normal self.n_item = self.train_set.num_items self.n_user = self.train_set.num_users self.alpha = self.init_params.get('alpha', train_set.global_mean) self.beta_u = self.init_params.get('beta_u', normal(self.n_user, std=0.01, random_state=self.seed)) self.beta_i = self.init_params.get('beta_i', normal(self.n_item, std=0.01, random_state=self.seed)) self.gamma_u = self.init_params.get('gamma_u', normal((self.n_user, self.k), std=0.01, random_state=self.seed)) self.gamma_i = self.init_params.get('gamma_i', normal((self.n_item, self.k), std=0.01, random_state=self.seed)) if self.trainable: self._fit_hft()
@staticmethod def _build_data(csr_mat): index_list = [] rating_list = [] for i in range(csr_mat.shape[0]): j, k = csr_mat.indptr[i], csr_mat.indptr[i + 1] index_list.append(csr_mat.indices[j:k]) rating_list.append(csr_mat.data[j:k]) return index_list, rating_list def _fit_hft(self): from .hft import Model from tqdm import trange # document data bow_mat = self.train_set.item_text.batch_bow(np.arange(self.n_item), keep_sparse=True) documents, _ = self._build_data(bow_mat) # bag of word feature # Rating data user_data = self._build_data(self.train_set.matrix) item_data = self._build_data(self.train_set.matrix.T.tocsr()) model = Model(n_user=self.n_user, n_item=self.n_item, alpha=self.alpha, beta_u=self.beta_u, beta_i=self.beta_i, gamma_u=self.gamma_u, gamma_i=self.gamma_i, n_vocab=self.vocab_size, k=self.k, lambda_text=self.lambda_text, l2_reg=self.l2_reg, grad_iter=self.grad_iter) model.init_count(docs=documents) # training loop = trange(self.max_iter, disable=not self.verbose) for _ in loop: model.assign_word_topics(docs=documents) loss = model.update_params(rating_data=(user_data, item_data)) loop.set_postfix(loss=loss) self.alpha, self.beta_u, self.beta_i, self.gamma_u, self.gamma_i = model.get_parameter() if self.verbose: print('Learning completed!')
[docs] def score(self, user_id, item_id=None): """Predict the scores/ratings of a user for an item. Parameters ---------- user_id: int, required The index of the user for whom to perform score prediction. item_id: int, optional, default: None The index of the item for that to perform score prediction. If None, scores for all known items will be returned. Returns ------- res : A scalar or a Numpy array Relative scores that the user gives to the item or to all known items """ if item_id is None: if self.train_set.is_unk_user(user_id): raise ScoreException("Can't make score prediction for (user_id=%d)" % user_id) known_item_scores = self.alpha + self.beta_u[user_id] + self.beta_i + self.gamma_i.dot( self.gamma_u[user_id, :]) return known_item_scores else: 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.alpha + self.beta_u[user_id] + self.beta_i[item_id] + self.gamma_i[item_id, :].dot( self.gamma_u[user_id, :]) return user_pred