A denoising diffusion probabilistic model synthesises galaxies that are qualitatively and physically indistinguishable from the real thing.

Realistic galaxy simulation via score-based generative models

Official code for 'Realistic galaxy simulation via score-based generative models'. We use a score-based generative model to produce realistic galaxy images. This implementation is based off of Phil Wang's PyTorch version which is in turn transcribed from Jonathan Ho's official Tensorflow version here.

Below are some outputs from our model. Half of these galaxies are real and half are generated. Check out the paper for the answer key.

Running the code

I will be adding full instructions to train and infer with this code within the next couple of days.

This Galaxy/APOD Does Not Exist

More galaxies can be found here.

We also used a DDPM to generate fake Astronomy Picture Of the Day imagery. Check it out.

Citing

If you find this work useful please consider citing our paper:

@article{smith2021,
    title={Realistic galaxy image simulation via score-based generative models},
    author={Michael J. Smith and James E. Geach and Ryan A. Jackson and Nikhil Arora and Connor Stone and St{\'{e}}ephane Courteau},
    journal = {arXiv e-prints},
    year={2021},
    eprint = {2111.01713}
}

Also be sure to check out Jonathan Ho's implementation here:

@article{ho2020,
    author = {{Ho}, Jonathan and {Jain}, Ajay and {Abbeel}, Pieter},
    title = "{Denoising Diffusion Probabilistic Models}",
    journal = {arXiv e-prints},
    year = 2020,
    eprint = {2006.11239},
}

And Jascha Sohl-Dickstein's original DDPM paper:

@article{sohl-dickstein2015,
    author = {{Sohl-Dickstein}, Jascha and {Weiss}, Eric A. and {Maheswaranathan}, Niru and {Ganguli}, Surya},
    title = "{Deep Unsupervised Learning using Nonequilibrium Thermodynamics}",
    journal = {arXiv e-prints},
    year = 2015,
    eprint = {1503.03585}
}

Contributing

AstroDDPM is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

AstroDDPM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with AstroDDPM. If not, see https://www.gnu.org/licenses/.