GNN-RecSys

This project was presented in a 40min talk + Q&A available on Youtube and in a Medium blog post

Graph Neural Networks for Recommender Systems
This repository contains code to train and test GNN models for recommendation, mainly using the Deep Graph Library (DGL).

What kind of recommendation?
For example, an organisation might want to recommend items of interest to all users of its ecommerce platforms.

How can this repository can be used?
This repository is aimed at helping users that wish to experiment with GNNs for recommendation, by giving a real example of code to build a GNN model, train it and serve recommendations.

No training data, experiments logs, or trained model are available in this repository.

What should the data look like?
To run the code, users need multiple data sources, notably interaction data between user and items and features of users and items.

The interaction data sources should be adjacency lists. Here is an example:

customer_id	item_id	timestamp	click	purchase
imbvblxwvtiywunh	3384934262863770	2018-01-01	0	1
nzhrkquelkgflone	8321263216904593	2018-01-01	1	0
...	...	...	...	...
cgatomzvjiizvctb	2756920171861146	2019-12-31	1	0
cnspkotxubxnxtzk	5150255386059428	2019-12-31	0	1

The feature data should have node identifier and node features:

customer_id	is_male	is_female
imbvblxwvtiywunh	0	1
nzhrkquelkgflone	1	0
...	...	...
cgatomzvjiizvctb	0	1
cnspkotxubxnxtzk	0	1

Run the code

There are 3 different usages of the code: hyperparametrization, training and inference. Examples of how to run the code are presented in UseCases.ipynb.

All 3 usages require specific files to be available. Please refer to the docstring to see which files are required.

Hyperparametrization

Hyperparametrization is done using the main.py file. Going through the space of hyperparameters, the loop builds a GNN model, trains it on a sample of training data, and computes its performance metrics. The metrics are reported in a result txt file, and the best model's parameters are saved in the models directory. Plots of the training experiments are saved in the plots directory. Examples of recommendations are saved in the outputs directory.

python main.py --from_beginning -v --visualization --check_embedding --remove 0.85 --num_epochs 100 --patience 5 --edge_batch_size 1024 --item_id_type 'ITEM IDENTIFIER' --duplicates 'keep_all'

Refer to docstrings of main.py for details on parameters.

Training

When the hyperparameters are selected, it is possible to train the chosen GNN model on the available data. This process saves the trained model in the models directory. Plots, training logs, and examples of recommendations are saved.

python main_train.py --fixed_params_path test/fixed_params_example.pkl --params_path test/params_example.pkl --visualization --check_embedding --remove .85 --edge_batch_size 512

Refer to docstrings of main_train.py for details on parameters.

Inference

With a trained model, it is possible to generate recommendations for all users or specific users. Examples of recommendations are printed.

python main_inference.py --params_path test/final_params_example.pkl --user_ids 123456 \
--user_ids 654321 --user_ids 999 \
--trained_model_path test/final_model_trained_example.pth --k 10 --remove .99

Refer to docstrings of main_inference.py for details on parameters.