EncT5

(Unofficial) Pytorch Implementation of EncT5: Fine-tuning T5 Encoder for Non-autoregressive Tasks

About

  • Finetune T5 model for classification & regression by only using the encoder layers.
  • Implemented of Tokenizer and Model for EncT5.
  • Add BOS Token (<s>) for tokenizer, and use this token for classification & regression.
    • Need to resize embedding as vocab size is changed. (model.resize_token_embeddings())
  • BOS and EOS token will be automatically added as below.
    • single sequence: <s> X </s>
    • pair of sequences: <s> A </s> B </s>

Requirements

Highly recommend to use the same version of transformers.

transformers==4.15.0
torch==1.8.1
sentencepiece==0.1.96
datasets==1.17.0
scikit-learn==0.24.2

How to Use

from enc_t5 import EncT5ForSequenceClassification, EncT5Tokenizer

model = EncT5ForSequenceClassification.from_pretrained("t5-base")
tokenizer = EncT5Tokenizer.from_pretrained("t5-base")

# Resize embedding size as we added bos token
if model.config.vocab_size < len(tokenizer.get_vocab()):
    model.resize_token_embeddings(len(tokenizer.get_vocab()))

Finetune on GLUE

Setup

  • Use T5 1.1 base for finetuning.
  • Evaluate on TPU. See run_glue_tpu.sh for more details.
  • Use AdamW optimizer instead of Adafactor.
  • Check best checkpoint on every epoch by using EarlyStoppingCallback.

Results

Metric Result (Paper) Result (Implementation)
CoLA Matthew 53.1 52.4
SST-2 Acc 94.0 94.5
MRPC F1/Acc 91.5/88.3 91.7/88.0
STS-B PCC/SCC 80.5/79.3 88.0/88.3
QQP F1/Acc 72.9/89.8 88.4/91.3
MNLI Mis/Matched 88.0/86.7 87.5/88.1
QNLI Acc 93.3 93.2
RTE Acc 67.8 69.7

GitHub

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