Incorporating Hierarchy into Text Encoder: a Contrastive Learning Approach for Hierarchical Text Classification

This repository implements a contrastive learning model for hierarchical text classification. This work has been accepted as the long paper "Incorporating Hierarchy into Text Encoder: a Contrastive Learning Approach for Hierarchical Text Classification" in ACL 2022.

Requirements

• Python >= 3.6
• torch >= 1.6.0
• transformers == 4.2.1
• fairseq >= 0.10.0
• torch-geometric == 1.7.2
• torch-scatter == 2.0.8
• torch-sparse == 0.6.12

Preprocess

Please download the original dataset and then use these scripts.

WebOfScience

The original dataset can be acquired in the repository of HDLTex. Preprocess code could refer to the repository of HiAGM and we provide a copy of preprocess code here. Please save the Excel data file Data.xlsx in WebOfScience/Meta-data as Data.txt.

cd ./data/WebOfScience
python preprocess_wos.py
python data_wos.py

NYT

The original dataset can be acquired here.

cd ./data/nyt
python data_nyt.py

RCV1-V2

The preprocess code could refer to the repository of reuters_loader and we provide a copy here. The original dataset can be acquired here by signing an agreement.

cd ./data/rcv1
python preprocess_rcv1.py
python data_rcv1.py

Train

usage: train.py [-h] [--lr LR] [--data {WebOfScience,nyt,rcv1}] [--batch BATCH] [--early-stop EARLY_STOP] [--device DEVICE] --name NAME [--update UPDATE] [--warmup WARMUP] [--contrast CONTRAST] [--graph GRAPH] [--layer LAYER]
                [--multi] [--lamb LAMB] [--thre THRE] [--tau TAU] [--seed SEED] [--wandb]

optional arguments:
  -h, --help            show this help message and exit
  --lr LR               Learning rate.
  --data {WebOfScience,nyt,rcv1}
                        Dataset.
  --batch BATCH         Batch size.
  --early-stop EARLY_STOP
                        Epoch before early stop.
  --device DEVICE		cuda or cpu. Default: cuda
  --name NAME           A name for different runs.
  --update UPDATE       Gradient accumulate steps
  --warmup WARMUP       Warmup steps.
  --contrast CONTRAST   Whether use contrastive model. Default: True
  --graph GRAPH         Whether use graph encoder. Default: True
  --layer LAYER         Layer of Graphormer.
  --multi               Whether the task is multi-label classification. Should keep default since all 
  						datasets are multi-label classifications. Default: True
  --lamb LAMB           lambda
  --thre THRE           Threshold for keeping tokens. Denote as gamma in the paper.
  --tau TAU             Temperature for contrastive model.
  --seed SEED           Random seed.
  --wandb               Use wandb for logging.

Checkpoints are in ./checkpoints/DATA-NAME. Two checkpoints are kept based on macro-F1 and micro-F1 respectively (checkpoint_best_macro.pt, checkpoint_best_micro.pt).

e.g. Train on WebOfScience with batch=12, lambda=0.05, gamma=0.02. Checkpoints will be in checkpoints/WebOfScience-test/.

python train.py --name test --batch 12 --data WebOfScience --lambda 0.05 --thre 0.02

Reproducibility

Contrastive learning is sensitive to hyper-parameters. We report results with fixed random seed but we observe higher results with unfixed seed.

• The results reported in the main table can be observed with following settings under seed=3.

WOS: lambda 0.05 thre 0.02
NYT: lambda 0.3 thre 0.002
RCV1: lambda 0.3 thre 0.001

We experiment on GeForce RTX 3090 (24G) with CUDA version $11.2$.

• The following settings can achieve higher results with unfixed seed (which we reported in the paper) .

WOS: lambda 0.1 thre 0.02
NYT: lambda 0.3 thre 0.005
RCV1: lambda 0.3 thre 0.005

• We also find that a higher tau (e.g. tau=2) is beneficial but we keep it to $1$ for simplicity.

Test

usage: test.py [-h] [--device DEVICE] [--batch BATCH] --name NAME [--extra {_macro,_micro}]

optional arguments:
  -h, --help            show this help message and exit
  --device DEVICE
  --batch BATCH         Batch size.
  --name NAME           Name of checkpoint. Commonly as DATA-NAME.
  --extra {_macro,_micro}
                        An extra string in the name of checkpoint. Default: _macro

Use --extra _macro or --extra _micro to choose from using checkpoint_best_macro.pt orcheckpoint_best_micro.pt respectively.

e.g. Test on previous example.

python test.py --name WebOfScience-test

Citation

@inproceedings{wang-etal-2022-incorporating,
    title = "Incorporating Hierarchy into Text Encoder: a Contrastive Learning Approach for Hierarchical Text Classification",
    author = "Wang, Zihan  and
      Wang, Peiyi  and
      Huang, Lianzhe  and
      Sun, Xin  and
      Wang, Houfeng",
    booktitle = "Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)",
    month = may,
    year = "2022",
    address = "Dublin, Ireland",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2022.acl-long.491",
    pages = "7109--7119",
}