transformers/docs/source/en/model_doc/splinter.md

Splinter

Overview

The Splinter model was proposed in Few-Shot Question Answering by Pretraining Span Selection by Ori Ram, Yuval Kirstain, Jonathan Berant, Amir Globerson, Omer Levy. Splinter is an encoder-only transformer (similar to BERT) pretrained using the recurring span selection task on a large corpus comprising Wikipedia and the Toronto Book Corpus.

The abstract from the paper is the following:

In several question answering benchmarks, pretrained models have reached human parity through fine-tuning on an order of 100,000 annotated questions and answers. We explore the more realistic few-shot setting, where only a few hundred training examples are available, and observe that standard models perform poorly, highlighting the discrepancy between current pretraining objectives and question answering. We propose a new pretraining scheme tailored for question answering: recurring span selection. Given a passage with multiple sets of recurring spans, we mask in each set all recurring spans but one, and ask the model to select the correct span in the passage for each masked span. Masked spans are replaced with a special token, viewed as a question representation, that is later used during fine-tuning to select the answer span. The resulting model obtains surprisingly good results on multiple benchmarks (e.g., 72.7 F1 on SQuAD with only 128 training examples), while maintaining competitive performance in the high-resource setting.

This model was contributed by yuvalkirstain and oriram. The original code can be found here.

Usage tips

• Splinter was trained to predict answers spans conditioned on a special [QUESTION] token. These tokens contextualize to question representations which are used to predict the answers. This layer is called QASS, and is the default behaviour in the [SplinterForQuestionAnswering] class. Therefore:
• Use [SplinterTokenizer] (rather than [BertTokenizer]), as it already contains this special token. Also, its default behavior is to use this token when two sequences are given (for example, in the run_qa.py script).
• If you plan on using Splinter outside run_qa.py, please keep in mind the question token - it might be important for the success of your model, especially in a few-shot setting.
• Please note there are two different checkpoints for each size of Splinter. Both are basically the same, except that one also has the pretrained weights of the QASS layer (tau/splinter-base-qass and tau/splinter-large-qass) and one doesn't (tau/splinter-base and tau/splinter-large). This is done to support randomly initializing this layer at fine-tuning, as it is shown to yield better results for some cases in the paper.

Resources

• Question answering task guide

SplinterConfig

autodoc SplinterConfig

SplinterTokenizer

autodoc SplinterTokenizer - build_inputs_with_special_tokens - get_special_tokens_mask - create_token_type_ids_from_sequences - save_vocabulary

SplinterTokenizerFast

autodoc SplinterTokenizerFast

SplinterModel

autodoc SplinterModel - forward

SplinterForQuestionAnswering

autodoc SplinterForQuestionAnswering - forward

SplinterForPreTraining

autodoc SplinterForPreTraining - forward