Materials Synthesizaability and Stability Prediction Using Semi-Superivsed Teacher-Student Dual Neural Network

Corresponding code for https://doi.org/10.1039/D2DD00098A

Citation:

D. Gleaves, E. Siriwardane, Y. Zhao, N. Fu and J. Hu, Digital Discovery, 2023, DOI: 10.1039/D2DD00098A.

Machine learning and evolution laboratory

Department of Computer Science and Engineering

University of South Carolina

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This software package implements the Meta Pseudo Labels (MPL) semi-supervised learning method with Crystal Graph Convolutional Neural Networks (CGCNN) with that takes an arbitary crystal structure to predict material synthesizability and whether it has positive or negative formation energy

The package provides two major functions:

• Train a semi-supervised TSDNN classification model with a customized dataset.
• Predict material synthesizability and formation energy of new crystals with a pre-trained TSDNN model.

The following paper describes the details of the CGCNN architecture, a graph neural network model for materials property prediction: CGCNN paper

The following paper describes the details of the semi-supervised learning framework that we used in our model: Meta Pseudo Labels

Table of Contents

• Prerequisites
• Usage
  • Define a customized dataset
  • Train a TSDNN model
  • Classify materials with a pre-trained TSDNN model
• Data
• Authors
• License

Prerequisites

This package requires:

• PyTorch
• scikit-learn
• pymatgen

If you are new to Python, the easiest way of installing the prerequisites is via conda. After installing conda, run the following command to create a new environment named cgcnn and install all prerequisites:

conda upgrade conda
conda create -n tsdnn python=3 scikit-learn pytorch torchvision pymatgen -c pytorch -c conda-forge

Alternatively, you can import our conda environment from the `environment.yml file:

conda create -n tsdnn
conda install -f environment.yml

*Note: this code is tested for PyTorch v1.0.0+ and is not compatible with versions below v0.4.0 due to some breaking changes.

This creates a conda environment for running TSDNN. Before using TSDNN, activate the environment by:

conda activate tsdnn

Usage

Define a customized dataset

To input crystal structures to TSDNN, you will need to define a customized dataset. Note that this is required for both training and predicting.

Before defining a customized dataset, you will need:

• CIF files recording the structure of the crystals that you are interested in
• The target label for each crystal (not needed for predicting, but you need to put some random numbers in data_test.csv)

You can create a customized dataset by creating a directory root_dir with the following files:

1. data_labeled.csv: a CSV file with two columns. The first column recodes a unique ID for each crystal, and the second column recodes the known value of the target label.

2. data_unlabeled.csv: a CSV file with two columns. The first column recodes a unique ID for each crystal, and the second column can be filled with alternating 1 and 0 (the second column is still needed).

3. atom_init.json: a JSON file that stores the initialization vector for each element. An example of atom_init.json is data/sample-regression/atom_init.json, which should be good for most applications.

4. ID.cif: a CIF file that recodes the crystal structure, where ID is the unique ID for the crystal.

(4.) data_predict: a CSV file with two columns. The first column recodes a unique ID for each crystal, and the second column can be filled with alternating 1 and 0 (the second column is still needed). This is the file that will be used if you want to classify materials with predict.py.

The structure of the root_dir should be:

root_dir
├── data_labeled.csv
├── data_unlabeled.csv
├── data_test.csv
├── data_positive.csv (optional- for positive and unlabeled dataset generation)
├── data_unlabeled_full.csv (optional- for positive and unlabeled dataset generation, data_unlabeled.csv will be overwritten)
├── atom_init.json
├── id0.cif
├── id1.cif
├── ...

There is an example of customized a dataset in: data/example.

Train a TSDNN model

Before training a new TSDNN model, you will need to:

• Define a customized dataset at root_dir to store the structure-property relations of interest.

Then, in directory synth-tsdnn, you can train a TSDNN model for your customized dataset by:

python main.py root_dir

If you want to use the PU learning dataset generation, you can train a model using the --uds flag with the number of PU iterations to perform.

python main.py --uds 5 root_dir

You can set the number of training, validation, and test data with labels --train-size, --val-size, and --test-size. Alternatively, you may use the flags --train-ratio, --val-ratio, --test-ratio instead. Note that the ratio flags cannot be used with the size flags simultaneously. For instance, data/example has 10 data points in total. You can train a model by:

python main.py --train-size 6 --val-size 2 --test-size 2 data/example

or alternatively

python main.py --train-ratio 0.6 --val-ratio 0.2 --test-ratio 0.2 data/example

After training, you will get 5 files in synth-tsdnn directory.

• checkpoints/teacher_best.pth.tar: stores the TSDNN teacher model with the best validation accuracy.
• checkpoints/student_best.pth.tar" stores the TSDNN student model with the best validation accuracy.
• checkpoints/t_checkpoint.pth.tar: stores the TSDNN teacher model at the last epoch.
• checkpoints/s_checkpoint.pth.tar: stores the TSDNN student model at the last epoch.
• results/validation/test_results.csv: stores the ID and predicted value for each crystal in training set.

Predict material properties with a pre-trained TSDNN model

Before predicting the material properties, you will need to:

• Define a customized dataset at root_dir for all the crystal structures that you want to predict.
• Obtain a pre-trained TSDNN model (example found in checkpoints/pre-trained/pre-train.pth.tar).

Then, in directory synth-tsdnn, you can predict the properties of the crystals in root_dir:

python predict.py checkpoints/pre-trained/pre-trained.pth.tar data/root_dir

After predicting, you will get one file in synth-tsdnn directory:

• predictions.csv: stores the ID and predicted value for each crystal in test set.

Data

To reproduce our paper, you can download the corresponding datasets following the download instructions. Each dataset discussed can be found in data/datasets/

Authors

This software was primarily written by Daniel Gleaves who was advised by Prof. Jianjun Hu. This software builds upon work by Tian Xie, Hieu Pham, and Jungdae Kim.

Acknowledgements

Research reported in this work was supported in part by NSF under grants 1940099 and 1905775. The views, perspective,and content do not necessarily represent the official views of NSF. This work was supported in part by the South Carolina Honors College Research Program. This work is partially supported by a grant from the University of South Carolina Magellan Scholar Program.

License

TSDNN is released under the MIT License.