Counting 3,463 Big Data & Machine Learning Frameworks, Toolsets, and Examples...
Suggestion? Feedback? Tweet @stkim1

NeuralCoref: Coreference Resolution in spaCy with Neural Networks.

NeuralCoref is a pipeline extension for spaCy 2.0 that annotates and resolves coreference clusters using a neural network. NeuralCoref is production-ready, integrated in spaCy's NLP pipeline and easily extensible to new training datasets.

For a brief introduction to coreference resolution and NeuralCoref, please refer to our blog post. NeuralCoref is written in Python/Cython and comes with pre-trained statistical models for English. It can be trained in other languages. NeuralCoref is accompanied by a visualization client NeuralCoref-Viz, a web interface powered by a REST server that can be tried online. NeuralCoref is released under the MIT license.

Version 3.0 out now! 100x faster and tightly integrated in spaCy pipeline.

Current Release Version spaCy Travis-CI NeuralCoref online Demo

Install NeuralCoref

As a pre-trained spaCy model

This is the easiest way to install NeuralCoref if you don't need to train the model on a new language or dataset.

Operating system macOS / OS X, Linux, Windows (Cygwin, MinGW, Visual Studio)
Python version CPython 2.7, 3.4+. Only 64 bit.

NeuralCoref is currently available in English with three models of increasing accuracy that mirror spaCy english models. The larger the model, the higher the accuracy:

Model Name MODEL_URL Size Description
en_coref_sm en_coref_sm 78 Mo A small English model based on spaCy en_core_web_sm-2.0.0
en_coref_md en_coref_md 161 Mo [Recommended] A medium English model based on spaCy en_core_web_md-2.0.0
en_coref_lg en_coref_lg 893 Mo A large English model based on spaCy en_core_web_lg-2.0.0

To install a model, copy the MODEL_URL of the model you are interested in from the above table and type:

pip install MODEL_URL

When using pip it is generally recommended to install packages in a virtual environment to avoid modifying system state:

venv .env
source .env/bin/activate
pip install MODEL_URL

Install NeuralCoref from source

Clone the repo and install using pip.

git clone
cd neuralcoref
pip install -e .


Loading NeuralCoref

NeuralCoref is integrated as a spaCy Pipeline Extension .

To load NeuralCoref, simply load the model you dowloaded above using spacy.load() with the model's name (e.g. en_coref_md) and process your text as usual with spaCy.

NeuralCoref will resolve the coreferences and annotate them as extension attributes in the spaCy Doc, Span and Token objects under the ._. dictionary.

Here is a simple example before we dive in greater details.

import spacy
nlp = spacy.load('en_coref_md')
doc = nlp(u'My sister has a dog. She loves him.')


You can also import NeuralCoref model directly and call its load() method:

import en_coref_md

nlp = en_coref_md.load()
doc = nlp(u'My sister has a dog. She loves him.')


Doc, Span and Token Extension Attributes

Attribute Type Description
doc._.has_coref boolean Has any coreference has been resolved in the Doc
doc._.coref_clusters list of Cluster All the clusters of corefering mentions in the doc
doc._.coref_resolved unicode Unicode representation of the doc where each corefering mention is replaced by the main mention in the associated cluster.
span._.is_coref boolean Whether the span has at least one corefering mention
span._.coref_cluster Cluster Cluster of mentions that corefer with the span
token._.in_coref boolean Whether the token is inside at least one corefering mention
token._.coref_clusters list of Cluster All the clusters of corefering mentions that contains the token

The Cluster class

The Cluster class is a small container for a cluster of mentions.

A Cluster contains 3 attributes:

Attribute Type Description
cluster.i int Index of the cluster in the Doc
cluster.main Span Span of the most representative mention in the cluster
cluster.mentions list of Span All the mentions in the cluster

The Cluster class also implements a few Python class methods to simplify the navigation inside a cluster:

Method Output Description
Cluster.__getitem__ return Span Access a mention in the cluster
Cluster.__iter__ yields Span Iterate over mentions in the cluster
Cluster.__len__ return int Number of mentions in the cluster


Here are a few examples on how you can navigate the coreference cluster chains and display clusters and mentions.

import spacy
nlp = spacy.load('en_coref_sm')
doc = nlp(u'My sister has a dog. She loves him')


token = doc[-1]

span = doc[-1:]

Important: NeuralCoref mentions are spaCy Span objects which means you can access all the usual Span attributes like span.start (index of the first token of the span in the document), span.end (index of the first token after the span in the document), etc...

Ex: doc._.coref_clusters[1].mentions[-1].start will give you the index of the first token of the last mention of the second coreference cluster in the document.

Using NeuralCoref as a server

A simple example of server script for integrating NeuralCoref in a REST API is provided as an example in examples/

There are many other ways you can manage and deploy NeuralCoref. Some examples can be found in spaCy Universe.

Re-train the model / Extend to another language

If you want to retrain the model or train it on another language, see our detailed training instructions as well as our detailed blog post

The training code will soon benefit from the same Cython refactoring than the inference code.