transformers/docs/source/en/model_doc/pegasus_x.md
Anton Vlasjuk d95c864a25
🔴🔴🔴 [Attention] Refactor Attention Interface for Bart-based Models (#38108)
* starting attn refactor for encoder decoder models via bart (eager + sdpa)

* flash attention works, remove unnecessary code

* flex attention support for bart!, gotta check if the renaming is not too aggressive

* some comments

* skip flex grad test for standalone as done with the other test

* revert flex attn rename (for now), sdpa simplify, and todos

* more todos

* refactor mask creation for reuse

* modular attempt at biogpt

* first batch of other models

* fix attn dropout

* fix autoformer copies

* hubert

* another batch of models

* copies/style + last round of bart models --> whisper next?

* remove unnecessary _reshape function and remove copy to whisper

* add skip for decoder-only models out of enc-dec (same as in bart)

* bring back licences

* remove comment, added to pr read instead

* mostly docs

* disable sew flex attn as it's unclear attn mask for now

* oops

* test fixes for enc-dec

* torch fx fixes + try at flex attn

* skip on mbart

* some more fixes

* musicgen skip / delete old attn class logic + sdpa compose compile skip

* disable flex attn for musicgen, not worth the effort

* more fixes and style

* flex attention test for dropout and encoder decoder that dont have main input names

* informer fixes

* the weirdest thing I've encountered yet...

* style

* remove empty tensor attempt, found core root in previous commits

* disable time series due to tests being very text centric on inputs

* add speech to text to be ignoring the other attns, also due to tests

* update docs

* remaining issues resolved ?

* update docs for current state --> nllb moe and pegasus x sdpa is questionable :D

* some models have not set the is_causal flag...

* change dtype in softmax tol old behaviour + some modular fixes

* I hate it but it is what it is

* fixes from main for bart

* forgot this one

* some model fixes

* style

* current status

* marian works now

* fixing some copies

* some copy fixes + time series x informer

* last models possibly and fixes on style/copies

* some post merge fixes

* more fixes

* make attention interface callable and move warnings there

* style lol

* add comment to "unsupported"

* remove callable interface and change interface warnings + some copies

* fix

* ternary is ugly af, make it simpler

* how did that happen

* fix flex attn test

* failing the test

* no more fallback! fixing copies next

* style + attn fixed

* fixing copies and mask creation

* wrong copy

* fixup tests and disable flex attn for now

* fixup last tests?
2025-05-22 17:12:58 +02:00

3.1 KiB

PEGASUS-X

PyTorch FlashAttention

Overview

The PEGASUS-X model was proposed in Investigating Efficiently Extending Transformers for Long Input Summarization by Jason Phang, Yao Zhao and Peter J. Liu.

PEGASUS-X (PEGASUS eXtended) extends the PEGASUS models for long input summarization through additional long input pretraining and using staggered block-local attention with global tokens in the encoder.

The abstract from the paper is the following:

While large pretrained Transformer models have proven highly capable at tackling natural language tasks, handling long sequence inputs continues to be a significant challenge. One such task is long input summarization, where inputs are longer than the maximum input context of most pretrained models. Through an extensive set of experiments, we investigate what model architectural changes and pretraining paradigms can most efficiently adapt a pretrained Transformer for long input summarization. We find that a staggered, block-local Transformer with global encoder tokens strikes a good balance of performance and efficiency, and that an additional pretraining phase on long sequences meaningfully improves downstream summarization performance. Based on our findings, we introduce PEGASUS-X, an extension of the PEGASUS model with additional long input pretraining to handle inputs of up to 16K tokens. PEGASUS-X achieves strong performance on long input summarization tasks comparable with much larger models while adding few additional parameters and not requiring model parallelism to train.

This model was contributed by zphang. The original code can be found here.

Documentation resources

PEGASUS-X uses the same tokenizer as PEGASUS.

PegasusXConfig

autodoc PegasusXConfig

PegasusXModel

autodoc PegasusXModel - forward

PegasusXForConditionalGeneration

autodoc PegasusXForConditionalGeneration - forward