Simple StyleGan2 for Pytorch

Simple working Pytorch implementation of Stylegan2 based on https://arxiv.org/abs/1912.04958

Below are some flowers that do not exist.

Neither do these hands

Install

You will need a machine with a GPU and CUDA installed. Then pip install the package like this

$ pip install stylegan2_pytorch

If you are using a windows machine, the following commands reportedly works.

$ conda install pytorch torchvision -c python
$ pip install stylegan2_pytorch

Use

$ stylegan2_pytorch --data /path/to/images

That's it. Sample images will be saved to results/default and models will be saved periodically to models/default.

Advanced Use

You can specify the name of your project with

$ stylegan2_pytorch --data /path/to/images --name my-project-name

You can also specify the location where intermediate results and model checkpoints should be stored with

$ stylegan2_pytorch --data /path/to/images --name my-project-name --results_dir /path/to/results/dir --models_dir /path/to/models/dir

By default, if the training gets cut off, it will automatically resume from the last checkpointed file. If you want to restart with new settings, just add a new flag

$ stylegan2_pytorch --new --data /path/to/images --name my-project-name --image-size 512 --batch-size 1 --gradient-accumulate-every 16 --network-capacity 10

Once you have finished training, you can generate images from your latest checkpoint like so.

$ stylegan2_pytorch  --generate

If a previous checkpoint contained a better generator, (which often happens as generators start degrading towards the end of training), you can load from a previous checkpoint with another flag

$ stylegan2_pytorch --generate --load-from {checkpoint number}

Bonus

Training on transparent images

$ stylegan2_pytorch --data ./transparent/images/path --transparent

Using half precision for greater memory savings

$ stylegan2_pytorch --data ./data --image-size 256 --fp16

Memory considerations

The more GPU memory you have, the bigger and better the image generation will be. Nvidia recommended having up to 16GB for training 1024x1024 images. If you have less than that, there are a couple settings you can play with so that the model fits.

$ stylegan2_pytorch --data /path/to/data \
    --batch-size 3 \
    --gradient-accumulate-every 5 \
    --network-capacity 16

1. Batch size - You can decrease the batch-size down to 1, but you should increase the gradient-accumulate-every correspondingly so that the mini-batch the network sees is not too small. This may be confusing to a layperson, so I'll think about how I would automate the choice of gradient-accumulate-every going forward.

2. Network capacity - You can decrease the neural network capacity to lessen the memory requirements. Just be aware that this has been shown to degrade generation performance.

Deployment on AWS

Below are some steps which may be helpful for deployment using Amazon Web Services. In order to use this, you will have to provision a GPU-backed EC2 instance. An appropriate instance type would be from a p2 or p3 series. I (iboates) tried a p2.xlarge (the cheapest option) and it was quite slow, slower in fact than using Google Colab. More powerful instance types may be better but they are more expensive. You can read more about them here.

Setup steps

1. Archive your training data and upload it to an S3 bucket
2. Provision your EC2 instance (I used an Ubuntu AMI)
3. Log into your EC2 instance via SSH
4. Install the aws CLI client and configure it:

sudo snap install aws-cli --classic
aws configure

You will then have to enter your AWS access keys, which you can retrieve from the management console under AWS Management Console > Profile > My Security Credentials > Access Keys

Then, run these commands, or maybe put them in a shell script and execute that:

mkdir data
curl -O https://bootstrap.pypa.io/get-pip.py
sudo apt-get install python3-distutils
python3 get-pip.py
pip3 install stylegan2_pytorch
export PATH=$PATH:/home/ubuntu/.local/bin
aws s3 sync s3://<Your bucket name> ~/data
cd data
tar -xf ../train.tar.gz

Now you should be able to train by simplying calling stylegan2_pytorch [args].

Notes:

• If you have a lot of training data, you may need to provision extra block storage via EBS.
• Also, you may need to spread your data across multiple archives.
• You should run this on a screen window so it won't terminate once you log out of the SSH session.

Appreciation

Thank you to Matthew Mann for his inspiring simple port for Tensorflow 2.0

References

@article{Karras2019stylegan2,
  title   = {Analyzing and Improving the Image Quality of {StyleGAN}},
  author  = {Tero Karras and Samuli Laine and Miika Aittala and Janne Hellsten and Jaakko Lehtinen and Timo Aila},
  journal = {CoRR},
  volume  = {abs/1912.04958},
  year    = {2019},
}

@article{,
  title= {Oxford 102 Flowers},
  author= {Nilsback, M-E. and Zisserman, A., 2008},
  abstract= {A 102 category dataset consisting of 102 flower categories, commonly occuring in the United Kingdom. Each class consists of 40 to 258 images. The images have large scale, pose and light variations.}
}

@article{afifi201911k,
  title={11K Hands: gender recognition and biometric identification using a large dataset of hand images},
  author={Afifi, Mahmoud},
  journal={Multimedia Tools and Applications},
  volume={78},
  number={15},
  pages={20835--20854},
  year={2019},
  publisher={Springer}
}