BLINK is an Entity Linking python library that uses Wikipedia as the target knowledge base.

The process of linking entities to Wikipedia is also known as Wikification.

news

• (September 2020) added ELQ - end-to-end entity linking on questions
• (3 July 2020) added FAISS support in BLINK - efficient exact/approximate retrieval

BLINK architecture

The BLINK architecture is described in the following paper:

@inproceedings{wu2019zero,
 title={Zero-shot Entity Linking with Dense Entity Retrieval},
 author={Ledell Wu, Fabio Petroni, Martin Josifoski, Sebastian Riedel, Luke Zettlemoyer},
 booktitle={EMNLP},
 year={2020}
}

https://arxiv.org/pdf/1911.03814.pdf

In a nutshell, BLINK uses a two stages approach for entity linking, based on fine-tuned BERT architectures. In the first stage, BLINK performs retrieval in a dense space defined by a bi-encoder that independently embeds the mention context and the entity descriptions. Each candidate is then examined more carefully with a cross-encoder, that concatenates the mention and entity text. BLINK achieves state-of-the-art results on multiple datasets.

ELQ architecture

ELQ does end-to-end entity linking on questions. The ELQ architecture is described in the following paper:

@inproceedings{li2020efficient,
 title={Efficient One-Pass End-to-End Entity Linking for Questions},
 author={Li, Belinda Z. and Min, Sewon and Iyer, Srinivasan and Mehdad, Yashar and Yih, Wen-tau},
 booktitle={EMNLP},
 year={2020}
}

https://arxiv.org/pdf/2010.02413.pdf

For more detail on how to run ELQ, refer to the ELQ README.

Use BLINK

1. Create conda environment and install requirements

(optional) It might be a good idea to use a separate conda environment. It can be created by running:

conda create -n blink37 -y python=3.7 && conda activate blink37
pip install -r requirements.txt

2. Download the BLINK models

The BLINK pretrained models can be downloaded using the following script:

chmod +x download_blink_models.sh
./download_blink_models.sh

We additionally provide a FAISS indexer in BLINK, which enables efficient exact/approximate retrieval for biencoder model.

• flat index
• hnsw (approximate search) index

To build and save FAISS (exact search) index yourself, run python blink/build_faiss_index.py --output_path models/faiss_flat_index.pkl

3. Use BLINK interactively

A quick way to explore the BLINK linking capabilities is through the main_dense interactive script. BLINK uses Flair for Named Entity Recognition (NER) to obtain entity mentions from input text, then run entity linking.

python blink/main_dense.py -i

Fast mode: in the fast mode the model only uses the bi-encoder, which is much faster (accuracy drops slightly, see details in "Benchmarking BLINK" section).

python blink/main_dense.py -i --fast

To run BLINK with saved FAISS index, run:

python blink/main_dense.py --faiss_index flat --index_path models/faiss_flat_index.pkl

or

python blink/main_dense.py --faiss_index hnsw --index_path models/faiss_hnsw_index.pkl

Example:

Bert and Ernie are two Muppets who appear together in numerous skits on the popular children's television show of the United States, Sesame Street.

Output:

Note: passing --show_url argument will show the Wikipedia url of each entity. The id number displayed corresponds to the order of entities in the entity.jsonl file downloaded from ./download_models.sh (starts from 0). The entity.jsonl file contains information of one entity per row (includes Wikipedia url, title, text, etc.).

4. Use BLINK in your codebase

pip install -e git+git@github.com:facebookresearch/BLINK#egg=BLINK

import blink.main_dense as main_dense
import argparse

models_path = "models/" # the path where you stored the BLINK models

config = {
    "test_entities": None,
    "test_mentions": None,
    "interactive": False,
    "top_k": 10,
    "biencoder_model": models_path+"biencoder_wiki_large.bin",
    "biencoder_config": models_path+"biencoder_wiki_large.json",
    "entity_catalogue": models_path+"entity.jsonl",
    "entity_encoding": models_path+"all_entities_large.t7",
    "crossencoder_model": models_path+"crossencoder_wiki_large.bin",
    "crossencoder_config": models_path+"crossencoder_wiki_large.json",
    "fast": False, # set this to be true if speed is a concern
    "output_path": "logs/" # logging directory
}

args = argparse.Namespace(**config)

models = main_dense.load_models(args, logger=None)

data_to_link = [ {
                    "id": 0,
                    "label": "unknown",
                    "label_id": -1,
                    "context_left": "".lower(),
                    "mention": "Shakespeare".lower(),
                    "context_right": "'s account of the Roman general Julius Caesar's murder by his friend Brutus is a meditation on duty.".lower(),
                },
                {
                    "id": 1,
                    "label": "unknown",
                    "label_id": -1,
                    "context_left": "Shakespeare's account of the Roman general".lower(),
                    "mention": "Julius Caesar".lower(),
                    "context_right": "'s murder by his friend Brutus is a meditation on duty.".lower(),
                }
                ]

_, _, _, _, _, predictions, scores, = main_dense.run(args, None, *models, test_data=data_to_link)

Benchmarking BLINK

We provide scripts to benchmark BLINK against popular Entity Linking datasets. Note that our scripts evaluate BLINK in a full Wikipedia setting, that is, the BLINK entity library contains all Wikipedia pages.

To benchmark BLINK run the following commands:

./scripts/get_train_and_benchmark_data.sh
python scripts/create_BLINK_benchmark_data.py
python blink/run_benchmark.py

The following table summarizes the performance of BLINK for the considered datasets.

dataset	biencoder accuracy (fast mode)	biencoder recall@10	biencoder recall@30	biencoder recall@100	crossencoder normalized accuracy	overall unnormalized accuracy	support
AIDA-YAGO2 testa	0.8145	0.9425	0.9639	0.9826	0.8700	0.8212	4766
AIDA-YAGO2 testb	0.7951	0.9238	0.9487	0.9663	0.8669	0.8027	4446
ACE 2004	0.8443	0.9795	0.9836	0.9836	0.8870	0.8689	244
aquaint	0.8662	0.9618	0.9765	0.9897	0.8889	0.8588	680
clueweb - WNED-CWEB (CWEB)	0.6747	0.8223	0.8609	0.8868	0.826	0.6825	10491
msnbc	0.8428	0.9303	0.9546	0.9676	0.9031	0.8509	617
wikipedia - WNED-WIKI (WIKI)	0.7976	0.9347	0.9546	0.9776	0.8609	0.8067	6383
TAC-KBP 20101	0.8898	0.9549	0.9706	0.9843	0.9517	0.9087	1019

¹ Licensed dataset available here.

The BLINK knowledge base

The BLINK knowledge base (entity library) is based on the 2019/08/01 Wikipedia dump, downloadable in its raw format from http://dl.fbaipublicfiles.com/BLINK/enwiki-pages-articles.xml.bz2

BLINK with solr as IR system

The first version of BLINK uses an Apache Solr based Information Retrieval system in combination with a BERT based cross-encoder. This IR-based version is now deprecated since it's outperformed by the current BLINK architecture. If you are interested in the old version, please refer to this README.

Troubleshooting

If the module cannot be found, preface the python command with PYTHONPATH=.

License

BLINK is MIT licensed. See the LICENSE file for details.