Model Architectures
Diffusion & score-based generation
Learn to reverse a gradual noising process, producing data by repeatedly transforming noise toward a sample.
Mental model
Start with static and repeatedly remove the predicted noise, guided by a time step and optional condition.
Data flow
- Clean training sample + sampled noise level
- Noisy sample
- U-Net or Transformer denoiser
- Noise / velocity / score estimate
- Iterative reverse sampler
How it trains
A network predicts noise, clean data, velocity, or a score at randomly sampled noise levels. Related flow-matching formulations learn a vector field between distributions.
How inference runs
Sampling integrates a learned reverse process across multiple steps. Sampler choice, step count, guidance, and seed trade speed, diversity, and fidelity.
Strengths
- Stable training relative to adversarial objectives
- Flexible conditioning and editing
- Strong coverage across image, audio, video, and scientific data
Trade-offs
- Iterative sampling is slower than a one-pass generator
- Guidance can reduce diversity or introduce artifacts
- The data representation and sampler materially affect results
Use it when
- High-dimensional conditional generation is central
- Multiple inference steps fit the latency budget
- Controls and sample quality can be evaluated jointly
Avoid or challenge it when
- One-pass generation is mandatory
- The model must run on a severely constrained device
- “Diffusion” is being treated as one fixed implementation
Illustrative published families
- • DDPM
- • Score-based models
- • Pixel-space diffusion systems
Commonly combines with
U-NetDiffusion TransformerLatent diffusion