Can Convolutional Neural Networks Crack Sudoku Puzzles?

Sudoku is a popular number puzzle that requires you to fill blanks in a 9X9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids contains all of the digits from 1 to 9. There have been various approaches to solving that, including computational ones. In this project, I show that simple convolutional neural networks have the potential to crack Sudoku without any rule-based postprocessing.

Requirements

• NumPy >= 1.11.1
• TensorFlow == 1.1

Background

• To see what Sudoku is, check the wikipedia
• To investigate this task comprehensively, read through McGuire et al. 2013.

Dataset

• 1M games were generated using generate_sudoku.py for training. I've uploaded them on the Kaggle dataset storage. They are available here.
• 30 authentic games were collected from http://1sudoku.com.

Model description

• 10 blocks of convolution layers of kernel size 3.

File description

• generate_sudoku.py create sudoku games. You don't have to run this. Instead, download pre-generated games.
• hyperparams.py includes all ajustable hyper parameters.
• data_load.py loads data and put them in queues so multiple mini-bach data are generated in parallel.
• modules.py contains some wrapper functions.
• train.py is for training.
• test.py is for test.

Training

• STEP 1. Download and extract training data.
• STEP 2. Run python train.py. Or download the pretrained file.

Test

• Run python test.py.

Evaluation Metric

Accuracy is defined as

Number of blanks where the prediction matched the solution / Number of blanks.

Results

Ater a couple of hours of training, the training curve seems to reach the optimum.