Source code for cornac.models.vaecf.recom_vaecf

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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 VAECF(Recommender): """Variational Autoencoder for Collaborative Filtering. Parameters ---------- k: int, optional, default: 10 The dimension of the stochastic user factors ``z''. h: int, optional, default: 20 The dimension of the deterministic hidden layer. n_epochs: int, optional, default: 100 The number of epochs for SGD. batch_size: int, optional, default: 100 The batch size. learning_rate: float, optional, default: 0.001 The learning rate for SGD_RMSProp. gamma: float, optional, default: 0.9 The weight for previous/current gradient in RMSProp. beta: float, optional, default: 1. The weight of the KL term as in beta-VAE. name: string, optional, default: 'VAECF' The name of the recommender model. trainable: boolean, optional, default: True When False, the model is not trained and Cornac assumes that the model is already \ pre-trained. verbose: boolean, optional, default: False When True, some running logs are displayed. seed: int, optional, default: None Random seed for parameters initialization. References ---------- * Liang, Dawen, Rahul G. Krishnan, Matthew D. Hoffman, and Tony Jebara. "Variational autoencoders for collaborative filtering." \ In Proceedings of the 2018 World Wide Web Conference on World Wide Web, pp. 689-698. """ def __init__(self, name="VAECF", k=10, h=20, n_epochs=100, batch_size=100, learning_rate=0.001, beta=1., gamma=0.9, trainable=True, verbose=False, seed=None, use_gpu=False): Recommender.__init__(self, name=name, trainable=trainable, verbose=verbose) self.k = k self.h = h self.batch_size = batch_size self.n_epochs = n_epochs self.learning_rate = learning_rate self.beta = beta self.gamma = gamma self.seed = seed self.use_gpu = use_gpu # 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 containing 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) if self.trainable: if self.verbose: print('Learning...') from .vaecf import learn res = learn(self.train_set, k=self.k, h=self.h, n_epochs=self.n_epochs, batch_size=self.batch_size, learn_rate=self.learning_rate, beta=self.beta, gamma=self.gamma, use_gpu=self.use_gpu, verbose=self.verbose, seed=self.seed) self.vae = res if self.verbose: print('Learning completed') elif self.verbose: print('%s is trained already (trainable = False)' % (self.name))
[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 """ import torch 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) x_u = self.train_set.matrix[user_id].copy() x_u.data = np.ones(len(x_u.data)) z_u, _ = self.vae.encode(torch.tensor(x_u.A, dtype=torch.double)) known_item_scores = self.vae.decode(z_u).data.cpu().numpy().flatten() 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)) x_u = self.train_set.matrix[user_id].copy() x_u.data = np.ones(len(x_u.data)) z_u, _ = self.vae.encode(torch.tensor(x_u.A, dtype=torch.double)) user_pred = self.vae.decode(z_u).data.cpu().numpy().flatten()[item_id] # Fix me I am not efficient return user_pred