Request for the full model file and code for MLM prediction using SBO head

[twadada]

I've found that you have shared the large model file with LM/SBO head here (https://dl.fbaipublicfiles.com/fairseq/models/spanbert_large_with_head.tar.gz); would you also provide the file for the base model?

Also, would you kindly provide a code that performs MLM prediction using SBO head (similar to BertPairTargetPredictionHead at pretraining/fairseq/models/pair_bert.py)? I'm curious about how it compares to the standard MLM.

[chantera]

I recently tried it as follows.

1. Prepare the SpanBERT model and its config.

Take model.pt from https://dl.fbaipublicfiles.com/fairseq/models/spanbert_large_with_head.tar.gz (#44) and config.json from https://dl.fbaipublicfiles.com/fairseq/models/spanbert_hf.tar.gz, and put them in a directory (e.g. spanbert_large_with_head).
Then, convert model.pt into pytorch_model.bin using the following code so that it can be used from huggingface/transformers.

from collections import OrderedDict
import torch

def convert(input_path, output_path):
    state_dict = OrderedDict()
    for k, v in torch.load(input_path).items():
        if k.startswith('decoder.'):
            state_dict[k[8:]] = v
    torch.save(state_dict, output_path)

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('input_path')
    parser.add_argument('output_path')
    args = parser.parse_args()
    convert(args.input_path, args.output_path)

2. Load SpanBERT using huggingface/transformers

from transformers import BertTokenizer, BertForMaskedLM

tokenizer = BertTokenizer.from_pretrained('bert-large-cased')
model = BertForMaskedLM.from_pretrained('./spanbert_large_with_head/')

seq = "Super Bowl 50 was {m} {m} {m} {m} to determine the champion".format(m=tokenizer.mask_token)
inputs = tokenizer(seq, return_tensors="pt")
outputs = model(**inputs).logits

print(tokenizer.decode([y if x == tokenizer.mask_token_id else x for x, y
                        in zip(inputs.input_ids[0], outputs.argmax(dim=2)[0])]))

In my env with transformers==4.1.1, this produced [CLS] Super Bowl 50 was the first football game to determine the champion [SEP].
The Hugging Face tutorial (https://huggingface.co/transformers/task_summary.html#masked-language-modeling) is also helpful.

I hope this will work for you.

[BigSalmon2]

@chantera I'm not sure why, but this was my result: "[CLS] Super Bowl 50 was Trilogy trailers Singers 231 to determine the champion [SEP]" Do you have any idea as to why?

[houliangxue]

Hi ! have you got the base mode with head?

[twadada]

No, I haven't -- I don't think it has been published anywhere.

[phosseini]

This is indeed helpful. Another thing to figure out is using the masking strategy of SpanBERT. Have you figured that out too? SpanBERT is different than the original BERT in two main aspects: 1) MLM prediction, the SBO head, 2) masking spans. The SBO head is available here, but I'm trying to figure out how to add the masking strategy too