Doc2EDAG

Source code for the paper, "Doc2EDAG: An End-to-End Document-level Framework for Chinese Financial Event Extraction", in EMNLP 2019.

Overview

Document-level Event Extraction (DEE) is urgently demanded in many applications but faces two major challenges:

• Arguments-scattering: arguments of a event record are always scattered across multiple sentences of a document.
• Multi-event: multiple event records with scattered arguments frequently coexists in one document.

Below we show an example to intuitively illustrate these two challenges.

To combat aforementioned challenges, we propose a truly end-to-end model, Doc2EDAG, for DEE, which can take a document as the input and directly emit event tables with multiple entries.

In general, the end-to-end DEE needs to complete the following tasks jointly:

• Entity Extraction (easy)
• Event Triggering (easy)
• Event Table Filling (hard)

How can Doc2EDAG achieve this?

It is owing to a novel structure, the entity-based directed acyclic graph (EDAG). Instead of directly filling a table, Doc2EDAG just generates an EDAG in an auto-regressive manner. In this way, a hard table filling task is decomposed into several path-expanding sub-tasks that are more tractable.

The following figure shows the overall architecture of Doc2EDAG, for more details, please refer to our paper.

Dataset

We utilize financial announcements of listed companies in China from 2008 to 2018 and build a large-scale dataset for DEE via distant supervision.

Run unzip Data.zip

Usage

Setup

Please use Python 3(.6) as well as the following packages:

torch >= 1.0.0
pytorch-pretrained-bert == 0.4.0
tensorboardX
numpy
tqdm

Training

For a machine with 8 GPUs, run

./train_multi.sh 8 --task_name [TASK_NAME]

If you want to use only 4 GPUs (Id 0,3,5,7), run

CUDA_VISIBLE_DEVICES=0,3,5,7 ./train_multi.sh 4 --task_name [TASK_NAME] --gradient_accumulation_steps 16

Please note that

• By setting a large step length of gradient accumulation, we can achieve large batch training with a few common GPUs. Specifically, for Titan X (12GB Memory), you should maintain B/(N*G) == 1, where B, N and G denote the batch size, the number of GPUs, and the step size of gradient accumulation, respectively.
• If you want to use BERT, just set --use_bert True, but using BERT requires much larger GPU memory (at least 24GB, the more the better).

Evaluation

To get evaluation results, run

./eval.sh --task_name [TASK_NAME] --eval_model_names DCFEE-O,DCFEE-M,GreedyDec,Doc2EDAG

You can run this evaluation script at any time after the start of training, and it will report the latest information.

Reproducing Experiments

To reproduce all experiments reported in our paper, just run

./reprod_all_exps.sh

Please note that we assume you have 8 GPUs each with 12GB memory and the total runtime can be very long.

Citation

If you find our work interesting, you can cite the paper as

@inproceedings{zheng2019doc2edag,
               title={{Doc2EDAG}: An End-to-End Document-level Framework for Chinese Financial Event Extraction},
               author={Zheng, Shun and Cao, Wei and Xu, Wei and Bian, Jiang},
               booktitle={EMNLP},
               year={2019}
}