Implementation of Denoising Diffusion Probabilistic Model in Pytorch. It is a new approach to generative modeling that may have the potential to rival GANs. It uses denoising score matching to estimate the gradient of the data distribution, followed by Langevin sampling to sample from the true distribution. This implementation was transcribed from the official Tensorflow version here.
$ pip install denoising_diffusion_pytorchimport torch
from denoising_diffusion_pytorch import Unet, GaussianDiffusion
model = Unet(
dim = 64,
dim_mults = (1, 2, 4, 8)
)
diffusion = GaussianDiffusion(
model,
image_size = 128,
timesteps = 1000, # number of steps
loss_type = 'l1' # L1 or L2
)
training_images = torch.randn(8, 3, 128, 128)
loss = diffusion(training_images)
loss.backward()
# after a lot of training
sampled_images = diffusion.sample(batch_size = 4)
sampled_images.shape # (4, 3, 128, 128)Or, if you simply want to pass in a folder name and the desired image dimensions, you can use the Trainer class to easily train a model.
from denoising_diffusion_pytorch import Unet, GaussianDiffusion, Trainer
model = Unet(
dim = 64,
dim_mults = (1, 2, 4, 8)
).cuda()
diffusion = GaussianDiffusion(
model,
image_size = 128,
timesteps = 1000, # number of steps
loss_type = 'l1' # L1 or L2
).cuda()
trainer = Trainer(
diffusion,
'path/to/your/images',
train_batch_size = 32,
train_lr = 2e-5,
train_num_steps = 700000, # total training steps
gradient_accumulate_every = 2, # gradient accumulation steps
ema_decay = 0.995, # exponential moving average decay
fp16 = True # turn on mixed precision training with apex
)
trainer.train()Samples and model checkpoints will be logged to ./results periodically
@misc{ho2020denoising,
title = {Denoising Diffusion Probabilistic Models},
author = {Jonathan Ho and Ajay Jain and Pieter Abbeel},
year = {2020},
eprint = {2006.11239},
archivePrefix = {arXiv},
primaryClass = {cs.LG}
}@inproceedings{anonymous2021improved,
title = {Improved Denoising Diffusion Probabilistic Models},
author = {Anonymous},
booktitle = {Submitted to International Conference on Learning Representations},
year = {2021},
url = {https://openreview.net/forum?id=-NEXDKk8gZ},
note = {under review}
}