Recent advances in continuous generative models, including multi-step approaches like diffusion and flow-matching (typically requiring 8-1000 sampling steps) and few-step methods such as consistency models (typically 1-8 steps), have demonstrated impressive generative performance. However, existing work often treats these approaches as distinct paradigms, resulting in separate training and sampling methodologies. We introduce a unified framework for training, sampling, and analyzing these models. Our implementation, the Unified Continuous Generative Models Trainer and Sampler (UCGM-{T,S}), achieves state-of-the-art (SOTA) performance. For example, on ImageNet 256x256 using a 675M diffusion transformer, UCGM-T trains a multi-step model achieving 1.30 FID in 20 steps and a few-step model reaching 1.42 FID in just 2 steps. Additionally, applying UCGM-S to a pre-trained model (previously 1.26 FID at 250 steps) improves performance to 1.06 FID in only 40 steps. Code is available at: https://github.com/LINs-lab/UCGM.
| Task | Dataset | Metric | Value | Model |
|---|---|---|---|---|
| Image Generation | ImageNet 512x512 | FID | 1.24 | DDT-XL/2 + UCGM-S (SD-VAE + 150 sampling steps + CFG) |
| Image Generation | ImageNet 512x512 | NFE | 300 | DDT-XL/2 + UCGM-S (SD-VAE + 150 sampling steps + CFG) |
| Image Generation | ImageNet 512x512 | FID | 1.25 | DDT-XL/2 + UCGM-S (SD-VAE + 100 sampling steps + CFG) |
| Image Generation | ImageNet 512x512 | NFE | 200 | DDT-XL/2 + UCGM-S (SD-VAE + 100 sampling steps + CFG) |
| Image Generation | ImageNet 256x256 | FID | 1.06 | SiT-XL/2 + UCGM-S (E2E-VAE + 40 sampling steps + CFG) |
| Image Generation | ImageNet 256x256 | NFE | 80 | SiT-XL/2 + UCGM-S (E2E-VAE + 40 sampling steps + CFG) |
| Image Generation | ImageNet 256x256 | FID | 1.21 | UCGM-XL/2 (VA-VAE + 30 sampling steps, without guidance) |
| Image Generation | ImageNet 256x256 | NFE | 30 | UCGM-XL/2 (VA-VAE + 30 sampling steps, without guidance) |
| Image Generation | ImageNet 256x256 | FID | 1.21 | UCGM-XL/2 (E2E-VAE + 40 sampling steps, without guidance) |
| Image Generation | ImageNet 256x256 | NFE | 40 | UCGM-XL/2 (E2E-VAE + 40 sampling steps, without guidance) |
| Image Generation | ImageNet 256x256 | FID | 1.21 | LightningDiT + UCGM-S (VA-VAE + 50 sampling steps + CFG) |
| Image Generation | ImageNet 256x256 | NFE | 100 | LightningDiT + UCGM-S (VA-VAE + 50 sampling steps + CFG) |