Source code for recbole.model.knowledge_aware_recommender.mkr

# -*- coding: utf-8 -*-
# @Time   : 2020/10/08
# @Author : Xinyan Fan
# @Email  : xinyan.fan@ruc.edu.cn

r"""
MKR
#####################################################
Reference:
    Hongwei Wang et al. "Multi-Task Feature Learning for Knowledge Graph Enhanced Recommendation." in WWW 2019.

Reference code:
    https://github.com/hsientzucheng/MKR.PyTorch
"""

import torch
import torch.nn as nn

from recbole.utils import InputType
from recbole.model.layers import MLPLayers
from recbole.model.abstract_recommender import KnowledgeRecommender
from recbole.model.init import xavier_normal_initialization


[docs]class MKR(KnowledgeRecommender): r"""MKR is a Multi-task feature learning approach for Knowledge graph enhanced Recommendation. It is a deep end-to-end framework that utilizes knowledge graph embedding task to assist recommendation task. The two tasks are associated by cross&compress units, which automatically share latent features and learn high-order interactions between items in recommender systems and entities in the knowledge graph. """ input_type = InputType.POINTWISE def __init__(self, config, dataset): super(MKR, self).__init__(config, dataset) # load parameters info self.LABEL = config['LABEL_FIELD'] self.embedding_size = config['embedding_size'] self.kg_embedding_size = config['kg_embedding_size'] self.L = config['low_layers_num'] # the number of low layers self.H = config['high_layers_num'] # the number of high layers self.reg_weight = config['reg_weight'] self.use_inner_product = config['use_inner_product'] self.dropout_prob = config['dropout_prob'] # init embeddings self.user_embeddings_lookup = nn.Embedding(self.n_users, self.embedding_size) self.item_embeddings_lookup = nn.Embedding(self.n_entities, self.embedding_size) self.entity_embeddings_lookup = nn.Embedding(self.n_entities, self.embedding_size) self.relation_embeddings_lookup = nn.Embedding(self.n_relations, self.embedding_size) # define layers lower_mlp_layers = [] high_mlp_layers = [] for i in range(self.L + 1): lower_mlp_layers.append(self.embedding_size) for i in range(self.H): high_mlp_layers.append(self.embedding_size * 2) self.user_mlp = MLPLayers(lower_mlp_layers, self.dropout_prob, 'sigmoid') self.tail_mlp = MLPLayers(lower_mlp_layers, self.dropout_prob, 'sigmoid') self.cc_unit = nn.Sequential() for i_cnt in range(self.L): self.cc_unit.add_module('cc_unit{}'.format(i_cnt), CrossCompressUnit(self.embedding_size)) self.kge_mlp = MLPLayers(high_mlp_layers, self.dropout_prob, 'sigmoid') self.kge_pred_mlp = MLPLayers([self.embedding_size * 2, self.embedding_size], self.dropout_prob, 'sigmoid') if self.use_inner_product == False: self.rs_pred_mlp = MLPLayers([self.embedding_size * 2, 1], self.dropout_prob, 'sigmoid') self.rs_mlp = MLPLayers(high_mlp_layers, self.dropout_prob, 'sigmoid') # loss self.sigmoid_BCE = nn.BCEWithLogitsLoss() # parameters initialization self.apply(xavier_normal_initialization)
[docs] def forward(self, user_indices=None, item_indices=None, head_indices=None, relation_indices=None, tail_indices=None): self.item_embeddings = self.item_embeddings_lookup(item_indices) self.head_embeddings = self.entity_embeddings_lookup(head_indices) self.item_embeddings, self.head_embeddings = self.cc_unit([self.item_embeddings, self.head_embeddings]) # calculate feature interactions between items and entities if user_indices is not None: # RS self.user_embeddings = self.user_embeddings_lookup(user_indices) self.user_embeddings = self.user_mlp(self.user_embeddings) if self.use_inner_product: # get scores by inner product. self.scores = torch.sum(self.user_embeddings * self.item_embeddings, 1) # [batch_size] else: # get scores by mlp layers self.user_item_concat = torch.cat([self.user_embeddings, self.item_embeddings], 1) # [batch_size, emb_dim*2] self.user_item_concat = self.rs_mlp(self.user_item_concat) self.scores = torch.squeeze(self.rs_pred_mlp(self.user_item_concat)) # [batch_size] self.scores_normalized = torch.sigmoid(self.scores) outputs = [self.user_embeddings, self.item_embeddings, self.scores, self.scores_normalized] if relation_indices is not None: # KGE self.tail_embeddings = self.entity_embeddings_lookup(tail_indices) self.relation_embeddings = self.relation_embeddings_lookup(relation_indices) self.tail_embeddings = self.tail_mlp(self.tail_embeddings) self.head_relation_concat = torch.cat([self.head_embeddings, self.relation_embeddings], 1) # [batch_size, emb_dim*2] self.head_relation_concat = self.kge_mlp(self.head_relation_concat) self.tail_pred = self.kge_pred_mlp(self.head_relation_concat) # [batch_size, 1] self.tail_pred = torch.sigmoid(self.tail_pred) self.scores_kge = torch.sigmoid(torch.sum(self.tail_embeddings * self.tail_pred, 1)) self.rmse = torch.mean( torch.sqrt(torch.sum(torch.pow(self.tail_embeddings - self.tail_pred, 2), 1) / self.embedding_size)) outputs = [self.head_embeddings, self.tail_embeddings, self.scores_kge, self.rmse] return outputs
def _l2_loss(self, inputs): return torch.sum(inputs ** 2) / 2
[docs] def calculate_rs_loss(self, interaction): r"""Calculate the training loss for a batch data of RS. """ # inputs self.user_indices = interaction[self.USER_ID] self.item_indices = interaction[self.ITEM_ID] self.head_indices = interaction[self.ITEM_ID] self.labels = interaction[self.LABEL] # RS model user_embeddings, item_embeddings, \ scores, scores_normalized = self.forward(user_indices=self.user_indices, item_indices=self.item_indices, head_indices=self.head_indices, relation_indices=None, tail_indices=None) # loss base_loss_rs = torch.mean(self.sigmoid_BCE(scores, self.labels)) l2_loss_rs = self._l2_loss(user_embeddings) + self._l2_loss(item_embeddings) loss_rs = base_loss_rs + l2_loss_rs * self.reg_weight return loss_rs
[docs] def calculate_kg_loss(self, interaction): r"""Calculate the training loss for a batch data of KG. """ # inputs self.item_indices = interaction[self.HEAD_ENTITY_ID] self.head_indices = interaction[self.HEAD_ENTITY_ID] self.relation_indices = interaction[self.RELATION_ID] self.tail_indices = interaction[self.TAIL_ENTITY_ID] # KGE model head_embeddings, tail_embeddings, \ scores_kge, rmse = self.forward(user_indices=None, item_indices=self.item_indices, head_indices=self.head_indices, relation_indices=self.relation_indices, tail_indices=self.tail_indices) # loss base_loss_kge = -scores_kge l2_loss_kge = self._l2_loss(head_embeddings) + self._l2_loss(tail_embeddings) loss_kge = base_loss_kge + l2_loss_kge * self.reg_weight return loss_kge.sum()
[docs] def predict(self, interaction): user = interaction[self.USER_ID] item = interaction[self.ITEM_ID] head = interaction[self.ITEM_ID] outputs = self.forward(user, item, head) _, _, scores, _ = outputs return scores
[docs]class CrossCompressUnit(nn.Module): r"""This is Cross&Compress Unit for MKR model to model feature interactions between items and entities. """ def __init__(self, dim): super(CrossCompressUnit, self).__init__() self.dim = dim self.fc_vv = nn.Linear(dim, 1, bias=True) self.fc_ev = nn.Linear(dim, 1, bias=True) self.fc_ve = nn.Linear(dim, 1, bias=True) self.fc_ee = nn.Linear(dim, 1, bias=True)
[docs] def forward(self, inputs): v, e = inputs # [batch_size, dim, 1], [batch_size, 1, dim] v = torch.unsqueeze(v, 2) e = torch.unsqueeze(e, 1) # [batch_size, dim, dim] c_matrix = torch.matmul(v, e) c_matrix_transpose = c_matrix.permute(0,2,1) # [batch_size * dim, dim] c_matrix = c_matrix.view(-1, self.dim) c_matrix_transpose = c_matrix_transpose.contiguous().view(-1, self.dim) # [batch_size, dim] v_intermediate = self.fc_vv(c_matrix) + self.fc_ev(c_matrix_transpose) e_intermediate = self.fc_ve(c_matrix) + self.fc_ee(c_matrix_transpose) v_output = v_intermediate.view(-1, self.dim) e_output = e_intermediate.view(-1, self.dim) return v_output, e_output