gptj-mnli / README.md
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metadata
license: apache-2.0
model-index:
  - name: Graphcore/gptj-mnli
    results:
      - task:
          name: Text Classification
          type: text-classification
        dataset:
          name: GLUE MNLI
          type: glue
          split: validation_mismatched
          args: mnli
        metrics:
          - name: Accuracy
            type: accuracy
            value: 0.825
            config: mnli_mismatched
datasets:
  - glue
  - multi_nli
tags:
  - pytorch
  - causal-lm
  - text-classification
  - text-generation
pipeline_task:
  - text-generation
widget:
  - text: >-
      mnli hypothesis: Your contributions were of no help with our students'
      education. premise: Your contribution helped make it possible for us to
      provide our students with a quality education. target:

Graphcore/gptj-mnli

This model is the fine-tuned version of EleutherAI/gpt-j-6B on the MNLI dataset

MNLI dataset consists of pairs of sentences, a premise and a hypothesis. The task is to predict the relation between the premise and the hypothesis, which can be:

  • entailment: hypothesis follows from the premise,
  • contradiction: hypothesis contradicts the premise,
  • neutral: hypothesis and premise are unrelated.

We finetune the model as a Causal Language Model (CLM): given a sequence of tokens, the task is to predict the next token. To achieve this, we create a stylised prompt string, following the approach of T5 paper.

mnli hypothesis: {hypothesis} premise: {premise} target: {class_label} <|endoftext|>

For example:

mnli hypothesis: Your contributions were of no help with our students' education. premise: Your contribution helped make it possible for us to provide our students with a quality education. target: contradiction <|endoftext|>

Fine-tuning and validation data

Fine tuning is done using the train split of the GLUE MNLI dataset and the performance is measured using the validation_mismatched split.

validation_mismatched means validation examples are not derived from the same sources as those in the training set and therefore not closely resembling any of the examples seen at training time.

Fine-tuning procedure

Fine tuned on a Graphcore IPU-POD64 using popxl.

Prompt sentences are tokenized and packed together to form 1024 token sequences, following HF packing algorithm. No padding is used. Since the model is trained to predict the next token, labels are simply the input sequence shifted by one token. Given the training format, no extra care is needed to account for different sequences: the model does not need to know which sentence a token belongs to.

Hyperparameters:

  • epochs:
  • optimiser: AdamW (beta1: 0.9, beta2: 0.999, eps: 1e-6, weight decay: 0.0, learning rate: 5e-6)
  • learning rate schedule: warmup schedule (min: 1e-7, max: 5e-6, warmup proportion: 0.005995)
  • batch size: 128

Performance

The resulting model matches SOTA performance with 82.5% accuracy.

Total number of examples                 9832
Number with badly formed result          0
Number with incorrect result             1725
Number with correct result               8107 
[82.5%]

example 0 = {'prompt_text': "mnli hypothesis: Your contributions were of no help with our students' education. premise: Your contribution helped make it possible for us to provide our students with a quality education. target:", 'class_label': 'contradiction'}
result = {'generated_text': ' contradiction'}

First 10 generated_text and expected class_label results:
 0: 'contradiction'                          contradiction
 1: 'contradiction'                          contradiction
 2: 'entailment'                             entailment
 3: 'contradiction'                          contradiction
 4: 'entailment'                             entailment
 5: 'entailment'                             entailment
 6: 'contradiction'                          contradiction
 7: 'contradiction'                          contradiction
 8: 'entailment'                             neutral
 9: 'contradiction'                          contradiction

How to use

The model can be easily loaded using AutoModelForCausalLM. You can use the pipeline API for text generation.

from transformers import pipeline, AutoModelForCausalLM, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained('EleutherAI/gpt-j-6B')
hf_model = AutoModelForCausalLM.from_pretrained("Graphcore/gptj-mnli", pad_token_id=tokenizer.eos_token_id)
generator =  pipeline('text-generation', model=hf_model, tokenizer=tokenizer)
prompt = "mnli hypothesis: Your contributions were of no help with our students' education." \
         "premise: Your contribution helped make it possible for us to provide our students with a quality education. target:"
out = generator(prompt, return_full_text=False, max_new_tokens=5, top_k=1)
# [{'generated_text': ' contradiction'}]