Everything Polynomial Diffuser

An efficient diffusion-based model for generating realistic traffic scene via polynomial representations.
This is the official repository of
EP-Diffuser: An Efficient Diffusion Model for Traffic Scene Generation and Prediction via Polynomial Representations

Model Pipeline

Examples on Argoverse 2 (In-Distribution)

Examples on Waymo (Out-of-Distribution)

Getting Started

1. Setup Environment

Step 1: Clone this repository:

git clone https://github.com/continental/EP-Diffuser.git
cd EP_Diffuser

Step 2: Create a new conda environment and install required packages:

conda create -n ep_diffuser python=3.10
conda activate ep_diffuser
pip install -r requirements.txt
pip install torch_cluster==1.6.3
pip install torch_scatter==2.1.2
pip install torchmetrics==1.6.0

Step 3: Download the Argoverse 2 Motion Forecasting Dataset following the Argoverse 2 User Guide. The dataset should be organized as follows:

/data/argo2/
├── train/
| ├── raw/
| | ├── aaaa-aaaa-aaaa/
| | ├── aaaa-aaaa-aaab/
| | ├── aaaa-aaaa-aaac/
└── val/
| ├── raw/
| | ├── aaaa-aaaa-aaaa/
| | ├── aaaa-aaaa-aaab/
| | ├── aaaa-aaaa-aaac/

Step 4: Download Waymo Open Motion Dataset (we use the scenario protocol). Same as Argoverse 2, organize the Waymo dataset as follows:

/data/waymo/
├── train/
| ├── raw/
| | ├── training.tfrecord-00000-of-01000/
| | ├── training.tfrecord-00001-of-01000/
| | ├── training.tfrecord-00002-of-01000/
└── val/
| ├── raw/
| | ├── validation.tfrecord-00000-of-00150/
| | ├── validation.tfrecord-00001-of-00150/
| | ├── validation.tfrecord-00002-of-00150/

2. Preprocessing

To start preprocessing for Argoverse 2, run:

python preprocess.py --root data/argo2/ --dataset argoverse2

To start preprocessing for Waymo, run:

python preprocess.py --root data/waymo/ --dataset waymo

Note
This preprocessing step will take considerable time.
It involves tracking trajectories of individual agents and fitting the map geometry.
The process will be slower initially but will accelerate as more maps are processed and cached.
Consider only preprocess the 'val' set of Waymo (e.g. only download the 'val' set)

After completion, two new folders will be created alongside the existing raw/ folder:

• processed/: Contains preprocessed data, including polynomial representations of trajectories and map geometry.
• sim_agent/: Contains transformed data required for computing Sim Agent metrics.

3. Training

To start training on Argoverse 2, run:

python train_ep_diffuser.py

Note
Training on Argoverse 2 takes ~2 days on a single A10G.

4. Evaluation

Evluation on 500 most challenging subsamples of Argoverse 2:

python eval_sim_agent_argo2.py --ckpt_path checkpoints/EP_Diffuser/checkpoints/epoch\=63-step\=399872.ckpt --val_subsample_path pickle_files/500C_A2_scenario_ids.pkl 

Evluation on 20% random subsamples of Argoverse 2:

python eval_sim_agent_argo2.py --ckpt_path checkpoints/EP_Diffuser/checkpoints/epoch\=63-step\=399872.ckpt --val_subsample_path pickle_files/R20P_A2_scenario_ids.pkl 

Evluation on 500 challenging subsamples of Waymo:

python eval_sim_agent_waymo.py --ckpt_path checkpoints/EP_Diffuser/checkpoints/epoch\=63-step\=399872.ckpt --val_subsample_path pickle_files/500C_WO_scenario_ids.pkl 

Evluation on 20% random subsamples of Waymo:

python eval_sim_agent_waymo.py --ckpt_path checkpoints/EP_Diffuser/checkpoints/epoch\=63-step\=399872.ckpt --val_subsample_path pickle_files/R20P_WO_scenario_ids.pkl 

Note
Calculating "Sim Agents" metrics is computationally expensive. For a more efficient alternative, consider using the CAT-K implementation. (We do not include it in our repository due to licensing restrictions).
For visualization, please refer to the implementation provided in the waymo-open-dataset.

5. Results and checkpoints

EP-Diffuser weights: weights.

In-Distribution Quantitative Results (6s Prediction Horizon)

Sub-samples	Train/Test	Realisim Meta	Kinematic	Interaction	Map	minADE
R20P	A2/A2	0.809	0.632	0.808	0.913	0.398
500C	A2/A2	0.713	0.507	0.707	0.838	0.546

Out-of-Distribution Quantitative Results (4.1s Prediction Horizon)

Sub-samples	Train/Test	Realisim Meta	Kinematic	Interaction	Map	minADE
R20P	A2/WO	0.788	0.491	0.834	0.900	0.348
500C	A2/WO	0.742	0.456	0.782	0.854	0.372

Note
Results may slightly vary from the reported values due to the inherent randomness in generation process.

Citation

If you find this repo useful, please consider giving us a star 🌟 and citing our related paper.

@article{yao2025ep,
title={EP-Diffuser: An Efficient Diffusion Model for Traffic Scene Generation and Prediction via Polynomial Representations},
author={Yue Yao and Mohamed-Khalil Bouzidi and Daniel Goehring and Joerg Reichardt},
year={2025},
journal={https://arxiv.org/abs/2504.05422}
}

Acknowledgements

This repo benefits from QCNet, Forecast-MAE, OptTrajDiff. Thanks for their great works.