NFC

This repository is the PyTorch implementation of our ACL-2022 [paper] (https://arxiv.org/abs/2109.12814)

Source code for Investigating Non-local Features for Neural Constituency Parsing.

Introduction
Usage
Citation
Credits

Introduction

We inject non-local sub-tree structure features to chart-based constituency parser by introducing two auxiliary training objectives.

Instance-level Pattern Loss

We define pattern as the n-gram constituents sharing the same parent, and ask model to predict the pattern based on span representation.

Corpus-level Consistency Loss

The consistency loss regularizes the co-occurrence between constituents and pattern by collecting corpus-level statistics.

NFC is developed on the basis of Self-Attentive Parser, whose code base is at this url.

Usage

To run our code:

$ pip install -r requirement.txt

For test:

python src/export test \
    --pretrained-model-path "bert-large-uncased" \
    --model-path path-to-the-checkpoint\
    --test-path path-to-the-test-file

If for Chinese, add '''--text-processing chinese''' and change the --pretrained-model-path.

We release our model checkpoints at Google Drive. (Models for PTB and for CTB5.1.)

To train a new parser:

For English:

$ RANDOM_SEED=42
$ python src/main.py train \
    --train-path data/02-21.10way.clean \
    --dev-path data/22.auto.clean \
    --subbatch-max-tokens 500 \
    --use-pretrained --pretrained-model bert-large-uncased  \
    --use-encoder --num-layers 2 \
    --max-consecutive-decays 10 --batch-size 64 \
    --use-pattern --pattern-num-threshold 5 --num-ngram "3" --pattern-loss-scale 1.0 \
    --use-compatible  --compatible-loss-scale 5.0 \
    --numpy-seed ${RANDOM_SEED} \
    --model-path-base models/ptb_bert_tri-task_negative-5_scale-5_${RANDOM_SEED}

For Chinese:

$ RANDOM_SEED=42
$ python src/main.py train \
--train-path data/ctb_5.1/ctb.train \
--dev-path data/ctb_5.1/ctb.dev \
--subbatch-max-tokens 500 \
--use-pretrained --pretrained-model pretrained_models/bert-base-chinese \
--max-consecutive-decays 10 --batch-size 32 \
--use-pattern \
--frequent-threshold 0.005 --num-ngram "2" --pattern-loss-scale 1.0 \
--use-compatible --compatible-loss-scale 5.0 \
--numpy-seed ${RANDOM_SEED} \
--text-processing chinese --predict-tags \
--model-path-base models/ctb_bert_tri-task_negative-5_scale-5_${RANDOM_SEED}

Citation

If you use this software for research, please cite our papers as follows:

@inproceedings{nfc,
    title = "Investigating Non-local Features for Neural Constituency Parsing",
    author = "Cui, Leyang  and Yang, Sen and Zhang, Yue" ,
    booktitle = "Proceedings of the 60th Conference of the Association for Computational Linguistics",
    year = "2022",
    publisher = "Association for Computational Linguistics",
}

Credits

The code in this repository is developed on the basis of the released code from https://github.com/mitchellstern/minimal-span-parser and https://github.com/nikitakit/self-attentive-parser.

Nealcly/nfc-parser

NFC

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