Source code for cornac.models.sorec.recom_sorec

# Copyright 2018 The Cornac Authors. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.
# ============================================================================

import numpy as np
import scipy

from ..recommender import Recommender
from ...utils.common import sigmoid
from ...utils.common import scale
from ...exception import ScoreException

[docs]class SoRec(Recommender): """Social recommendation using Probabilistic Matrix Factorization. Parameters ---------- k: int, optional, default: 5 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: 0.001 The learning rate for SGD_RMSProp. gamma: float, optional, default: 0.9 The weight for previous/current gradient in RMSProp. lamda: float, optional, default: 0.001 The regularization parameter. lamda_c: float, optional, default: 10 The parameter balancing the information from the user-item rating matrix and the user social network. weight_link: boolean, optional, default: True When true the social network links are weighted according to eq. (4) in the original paper. name: string, optional, default: 'SOREC' 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, V and Z 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, 'Z':Z}. U: a ndarray of shape (n_users, k) Containing the user latent factors. V: a ndarray of shape (n_items, k) Containing the item latent factors. Z: a ndarray of shape (n_users, k) Containing the social network latent factors. seed: int, optional, default: None Random seed for parameters initialization. References ---------- * H. Ma, H. Yang, M. R. Lyu, and I. King. SoRec:Social recommendation using probabilistic matrix factorization. \ CIKM ’08, pages 931–940, Napa Valley, USA, 2008. """ def __init__( self, name="SoRec", k=5, max_iter=100, learning_rate=0.001, lamda_c=10, lamda=0.001, gamma=0.9, weight_link=True, trainable=True, verbose=False, init_params=None, seed=None, ): Recommender.__init__(self, name=name, trainable=trainable, verbose=verbose) self.k = k self.max_iter = max_iter self.learning_rate = learning_rate self.lamda_c = lamda_c self.lamda = lamda self.gamma = gamma self.weight_link = weight_link self.ll = np.full(max_iter, 0) self.eps = 0.000000001 self.seed = seed # Init params if provided self.init_params = {} if init_params is None else init_params self.U = self.init_params.get("U", None) # matrix of user factors self.V = self.init_params.get("V", None) # matrix of item factors self.Z = self.init_params.get("Z", None) # matrix of social network factors if self.U is not None and self.U.shape[1] != self.k: raise ValueError("initial parameters U dimension error") if self.V is not None and self.V.shape[1] != self.k: raise ValueError("initial parameters V dimension error") if self.Z is not None and self.Z.shape[1] != self.k: raise ValueError("initial parameters Z dimension error")
[docs] def fit(self, train_set, val_set=None): """Fit the model to observations. Parameters ---------- train_set: :obj:``, required User-Item preference data as well as additional modalities. val_set: :obj:``, optional, default: None User-Item preference data for model selection purposes (e.g., early stopping). Returns ------- self : object """, train_set, val_set) import math from cornac.models.sorec import sorec if self.trainable: # user-item interactions (rat_uid, rat_iid, rat_val) = train_set.uir_tuple # user social network map_uid = train_set.user_indices (net_uid, net_jid, net_val) = train_set.user_graph.get_train_triplet( map_uid, map_uid ) if self.weight_link: degree = train_set.user_graph.get_node_degree(map_uid, map_uid) weighted_net_val = [] for u, j, val in zip(net_uid, net_jid, net_val): u_out = degree[int(u)][1] j_in = degree[int(j)][0] val_weighted = math.sqrt(j_in / (j_in + u_out)) * val weighted_net_val.append(val_weighted) net_val = weighted_net_val if [self.train_set.min_rating, self.train_set.max_rating] != [0, 1]: if self.train_set.min_rating == self.train_set.max_rating: rat_val = scale(rat_val, 0.0, 1.0, 0.0, self.train_set.max_rating) else: rat_val = scale( rat_val, 0.0, 1.0, self.train_set.min_rating, self.train_set.max_rating, ) rat_val = np.array(rat_val, dtype="float32") rat_uid = np.array(rat_uid, dtype="int32") rat_iid = np.array(rat_iid, dtype="int32") net_val = np.array(net_val, dtype="float32") net_uid = np.array(net_uid, dtype="int32") net_jid = np.array(net_jid, dtype="int32") if self.verbose: print("Learning...") res = sorec.sorec( rat_uid, rat_iid, rat_val, net_uid, net_jid, net_val, k=self.k, n_users=train_set.num_users, n_items=train_set.num_items, n_ratings=len(rat_val), n_edges=len(net_val), n_epochs=self.max_iter, lamda_c=self.lamda_c, lamda=self.lamda, learning_rate=self.learning_rate, gamma=self.gamma, init_params={"U": self.U, "V": self.V, "Z": self.Z}, verbose=self.verbose, seed=self.seed, ) self.U = np.asarray(res["U"]) self.V = np.asarray(res["V"]) self.Z = np.asarray(res["Z"]) if self.verbose: print("Learning completed") elif self.verbose: print("%s is trained already (trainable = False)" % return self
[docs] def score(self, user_idx, item_idx=None): """Predict the scores/ratings of a user for an item. Parameters ---------- user_idx: int, required The index of the user for whom to perform score prediction. item_idx: int, optional, default: None The index of the item for which 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_idx is None: if self.train_set.is_unk_user(user_idx): raise ScoreException( "Can't make score prediction for (user_id=%d)" % user_idx ) known_item_scores =[user_idx, :]) return known_item_scores else: if self.train_set.is_unk_user(user_idx) or self.train_set.is_unk_item( item_idx ): raise ScoreException( "Can't make score prediction for (user_id=%d, item_id=%d)" % (user_idx, item_idx) ) user_pred = self.V[item_idx, :].dot(self.U[user_idx, :]) user_pred = sigmoid(user_pred) if self.train_set.min_rating == self.train_set.max_rating: user_pred = scale(user_pred, 0.0, self.train_set.max_rating, 0.0, 1.0) else: user_pred = scale( user_pred, self.train_set.min_rating, self.train_set.max_rating, 0.0, 1.0, ) return user_pred