UL2
UL2 is a research and open-weight text-to-text language model using a mixture-of-denoisers pretraining objective. It combines regular span corruption, sequential denoising, and extreme corruption to unify language-understanding and generation tasks. The released 20B model uses a T5-style encoder-decoder and mode tokens that select the desired learning behavior. It became a foundation for instruction tuning and chain-of-thought research.
2022-05-10
20B
T5-style encoder-decoder Transformer trained with a mixture-of-denoisers objective
Apache-2.0
Specifications
- Parameters
- 20B
- Architecture
- T5-style encoder-decoder Transformer trained with a mixture-of-denoisers objective
- License
- Apache-2.0
- Context Window
- 512 tokens
- Type
- text
- Modalities
- text
Benchmark Scores
Advanced Specifications
- Model Family
- UL2
- API Access
- Not Available
- Chat Interface
- Not Available
- Hardware Support
- GPUTPUCPU
Capabilities & Limitations
- Capabilities
- text-to-text generationquestion answeringsummarizationreasoning
- Known Limitations
- The original checkpoint was trained with 512-token input and target sequences.Mode-token handling and task prompting affect quality.
- Notable Use Cases
- NLP researchtask fine-tuningencoder-decoder experimentation