Machine Scheduling Problem Using Deep Reinforcement Learning

In this research project, we propose a sophisticated approach for Machine Scheduling Problem (MSP) using deep reinforcement learning, where we address the MSP problem especially for the Fabric Industry. However, the presented method is not only limited to it.

The complete documentation is available on Read the Docs.

NOTE: This research has been conducted at LIMOS in Clermont-Ferrand, France as a part of research internship.

Table of contents

• Description
• Usage
• Infrastructure
• Conclusion

Description

In this research, we design Deep Learning model to sovle MSP problem (NP-hard combinatorial optimization problem) where the goal is to find a schedule from combinatorial search space such that it minimizes makespan (i.e., an objective) under certain constraints.

To define the MSP problem, we employ graph structure to model the various interaction between machines and jobs. We cast the MSP as a Graph-to-Sequence machine learning problem that follows the standard encoder-decoder architecture consisting of graph encoder, and a recurrent decoder. We train the model using a policy-gradient reinforcement learning algorithm, namely REINFORCE algorithm. Furthermore, we also present different novel masking strategies to filter out the invalid action at any timestep during the decoding.

To access the full research document, send the Request Email to mohammedbilalansari.official@gmail.com

Usage

The msp package is based on low-level API of tensorflow. To install it and all its dependencies, you need to download a code repository and run a make build command. Make sure you have make utility install on your system.

make build

To run the program on your system. Pass the following command with appropriate configuration file and action. Configuration files are available inside the bin folder. Possible values of actions are run_solver, train_model, test_model, or train_and_test_model. Refer flag.py file inside bin folder for more details about flags.

python bin/main.py --config_path=bin/configs/exact_solver_msp_5_2_copy.yml --action='train_model'

To run it on HPC (High Performance Computing) cluster managed by slurm.

export config_path=bin/configs/rl_model_msp_5_2.yml
export action=train_model
sbatch slurm.sh export=config_path,action

Another way to use the package is programmatically

Sample code to run the ExactSolver on synthetic data.

# Run the exact solver
from msp.solvers import ExactSolver
from msp.datasets import make_sparse_data

n_instances = 640
dataset = make_sparse_data(n_instances, seed=2021) 
solver = ExactSolver()

for msp_batch_instance in dataset.batch(32):
    best_schedule, makespan = solver(msp_batch_instance)
    # store all best_schedule in an appropriate way

Sample code to create the instanace of MSP model.

# create a model instanace
from msp.models import MSPModel
from msp.models.encoders import GGCNEncoder
from msp.models.decoders import AttentionDecoder

encoder_params = {'units': 32}
decoder_params = {'units': 32}
model = MSPModel(GGCNEncoder, encoder_params, AttentionDecoder, decoder_params)

Infrastructure

We run all experiments on NVIDIA Tesla V100 32GB GPU of HPC (high-performance computing) cluster of the HSE University.

Conclusion

In this research, we proposed a sophisticated approach for Machine Scheduling Problem(MSP) using deep reinforcement learning, where we formulated MSP as a Graph-to-Sequence machine learning problem. We also presented novel masking strategies to filter out the invalid action at any timestep. Our approach outperforms both exhaustive search and random searchmethods in terms of associated inference time with a narrow objective gap.