echarlaix/bert-base-uncased-sst2-acc91.1-d37-hybrid

bert-base-uncased model fine-tuned on SST-2

This model was created using the nn_pruning python library: the linear layers contains 37% of the original weights.

The model contains 51% of the original weights overall (the embeddings account for a significant part of the model, and they are not pruned by this method).

In terms of perfomance, its accuracy is 91.17.

Fine-Pruning details

This model was fine-tuned from the HuggingFace model checkpoint on task, and distilled from the model textattack/bert-base-uncased-SST-2. This model is case-insensitive: it does not make a difference between english and English.

A side-effect of the block pruning method is that some of the attention heads are completely removed: 88 heads were removed on a total of 144 (61.1%). Here is a detailed view on how the remaining heads are distributed in the network after pruning.

Details of the SST-2 dataset

Dataset	Split	# samples
SST-2	train	67K
SST-2	eval	872

Results

Pytorch model file size: 351MB (original BERT: 420MB)

Metric	# Value	# Original (Table 2)	Variation
accuracy	91.17	92.7	-1.53

Example Usage

Install nn_pruning: it contains the optimization script, which just pack the linear layers into smaller ones by removing empty rows/columns.

pip install nn_pruning

Then you can use the transformers library almost as usual: you just have to call optimize_model when the pipeline has loaded.

from transformers import pipeline
from nn_pruning.inference_model_patcher import optimize_model

cls_pipeline = pipeline(
    "text-classification",
    model="echarlaix/bert-base-uncased-sst2-acc91.1-d37-hybrid",
    tokenizer="echarlaix/bert-base-uncased-sst2-acc91.1-d37-hybrid",
)

print(f"Parameters count (includes only head pruning, no feed forward pruning)={int(cls_pipeline.model.num_parameters() / 1E6)}M")
cls_pipeline.model = optimize_model(cls_pipeline.model, "dense")
print(f"Parameters count after optimization={int(cls_pipeline.model.num_parameters() / 1E6)}M")
predictions = cls_pipeline("This restaurant is awesome")
print(predictions)