Deep Equilibrium Approaches to Diffusion Models

Ashwini Pokle, Zhengyang Geng and Zico Kolter, NeurIPS 2022 [arxiv link]

This codebase has been adapted largely from the repository of Denoising Diffusion Implicit Models (DDIM) by Song. et. al. 2020 (https://arxiv.org/abs/2010.02502) (Note: we include the original MIT license that belongs to the authors of prior work (Song. et. al.) in this codebase.)

Getting Started

Create conda environment and install all packages from requirements.txt

conda create --name <environment_name> --file requirements.txt
conda activate <environment_name>

If you are working with CelebA 64x64 dataset, please download pretrained checkpoint from https://github.com/ermongroup/ddim If you are working with any of the other datasets like CIFAR10, LSUN Bedrooms or Outdoor Churches, please update the path to your cache directory here

Running the Experiments

The code has been tested on PyTorch 1.11.

Sampling

Sampling for FID evaluation

General command to sample with a DEQ or DDIM is:

python main.py --config {DATASET}.yml --model Diffusion --exp {PROJECT_PATH} --image_folder {IMG_FOLDER} --doc {DOCUMENTATIOIN_FOLDER} --sample --fid --timesteps 1000 --eta 0 --ni --method {METHOD} --use_pretrained

where

• ETA controls the scale of the variance (0 is DDIM, and 1 is one type of DDPM).
• STEPS controls how many timesteps used in the process.
• MODEL_NAME finds the pre-trained checkpoint according to its inferred path.
• METHOD Use 'anderson' for DEQ and 'simple-seq' for DDIM

Please check generate_deq_convergence.sh for sampling commands for all the datasets.

Example command for sampling with DEQ from CIFAR10

python main.py --config cifar10.yml --model Diffusion --exp cifar10-orig-fid --image_folder samples-cifar10-and-t1000-long-new --doc cifar10 --sample --fid --timesteps 1000 --eta 0 --ni --method anderson --use_pretrained

The --use_pretrained option will automatically load the model according to the dataset for CIFAR10, LSUN Bedrooms and Churches. We use DDPM models for all datasets except CelebA. Please download CelebA 64x64 pretrained model from https://github.com/ermongroup/ddim

Training DEQ for Model Inversion

 python main.py --config {DATASET}_ls_opt.yml --model DiffusionInversion --exp {PROJECT_PATH} --image_folder {IMAGE_FOLDER} --doc {MODEL_NAME} --ls_opt --timesteps {STEPS} --ni --method {METHOD} --lambda1 1 --lambda2 0 --lambda3 0 --seed $i --tau {DAMPING_FACTOR} --use_wandb --no_augmentation --pg_steps {PG_STEPS}

where

• ETA controls the scale of the variance (0 is DDIM, and 1 is one type of DDPM).
• STEPS controls how many timesteps used in the process.
• MODEL_NAME finds the pre-trained checkpoint according to its inferred path.
• METHOD Use 'anderson' for DEQ and 'simple-seq' for DDIM
• PG_STEPS is the number of iterations while computing phantom gradients. We set this value to 1.
• DAMPING_FACTOR is the value of damping used in phantom gradients. We set this to 0.1.

Please check invert_models.sh for sampling commands for all the datasets.