anaGo

anaGo is a state-of-the-art library for sequence labeling using Keras.

anaGo can performs named-entity recognition (NER), part-of-speech tagging (POS tagging), semantic role labeling (SRL) and so on for many languages. For example, English Named-Entity Recognition is shown in the following picture:

Japanese Named-Entity Recognition is shown in the following picture:

Similarly, you can solve your task for your language. You have only to prepare input and output data. :)

Feature Support

anaGo provide following features:

• learning your own task without any knowledge.
• defining your own model.
• (Not yet supported)downloading learned model for many tasks. (e.g. NER, POS Tagging, etc...)

Install

To install anaGo, simply run:

$ pip install anago

or install from the repository:

$ git clone https://github.com/Hironsan/anago.git
$ cd anago
$ pip install -r requirements.txt

Data and Word Vectors

The data must be in the following format(tsv). We provide an example in train.txt:

EU	B-ORG
rejects	O
German	B-MISC
call	O
to	O
boycott	O
British	B-MISC
lamb	O
.	O

Peter	B-PER
Blackburn	I-PER

You also need to download GloVe vectors and store it in data/glove.6B directory.

Get Started

Import

First, import the necessary modules:

import os
import anago
from anago.data.reader import load_data_and_labels, load_word_embeddings
from anago.data.preprocess import prepare_preprocessor
from anago.config import ModelConfig, TrainingConfig

They include loading modules, a preprocessor and configs.

And set parameters to use later:

DATA_ROOT = 'data/conll2003/en/ner'
SAVE_ROOT = './models'  # trained model
LOG_ROOT = './logs'     # checkpoint, tensorboard
embedding_path = './data/glove.6B/glove.6B.100d.txt'
model_config = ModelConfig()
training_config = TrainingConfig()

Loading data

After importing the modules, read data for training, validation and test:

train_path = os.path.join(DATA_ROOT, 'train.txt')
valid_path = os.path.join(DATA_ROOT, 'valid.txt')
test_path = os.path.join(DATA_ROOT, 'test.txt')
x_train, y_train = load_data_and_labels(train_path)
x_valid, y_valid = load_data_and_labels(valid_path)
x_test, y_test = load_data_and_labels(test_path)

After reading the data, prepare preprocessor and pre-trained word embeddings:

p = prepare_preprocessor(x_train, y_train)
embeddings = load_word_embeddings(p.vocab_word, embedding_path, model_config.word_embedding_size)
model_config.vocab_size = len(p.vocab_word)
model_config.char_vocab_size = len(p.vocab_char)

Now we are ready for training :)

Training a model

Let's train a model. For training a model, we can use Trainer. Trainer manages everything about training. Prepare an instance of Trainer class and give train data and valid data to train method:

trainer = anago.Trainer(model_config, training_config, checkpoint_path=LOG_ROOT, save_path=SAVE_ROOT,
                        preprocessor=p, embeddings=embeddings)
trainer.train(x_train, y_train, x_valid, y_valid)

If training is progressing normally, progress bar will be displayed as follows:

...
Epoch 3/15
702/703 [============================>.] - ETA: 0s - loss: 60.0129 - f1: 89.70
703/703 [==============================] - 319s - loss: 59.9278   
Epoch 4/15
702/703 [============================>.] - ETA: 0s - loss: 59.9268 - f1: 90.03
703/703 [==============================] - 324s - loss: 59.8417   
Epoch 5/15
702/703 [============================>.] - ETA: 0s - loss: 58.9831 - f1: 90.67
703/703 [==============================] - 297s - loss: 58.8993   
...

Evaluating a model

To evaluate the trained model, we can use Evaluator. Evaluator performs evaluation. Prepare an instance of Evaluator class and give test data to eval method:

weights = 'model_weights.h5'

evaluator = anago.Evaluator(model_config, weights, save_path=SAVE_ROOT, preprocessor=p)
evaluator.eval(x_test, y_test)

After evaluation, F1 value is output:

- f1: 90.67

Tagging a sentence

To tag any text, we can use Tagger. Prepare an instance of Tagger class and give text to tag method:

weights = 'model_weights.h5'
tagger = anago.Tagger(model_config, weights, save_path=SAVE_ROOT, preprocessor=p)

Let's try tagging a sentence, "President Obama is speaking at the White House." We can do it as follows:

>>> sent = 'President Obama is speaking at the White House.'
>>> print(tagger.tag(sent))
[('President', 'O'), ('Obama', 'PERSON'), ('is', 'O'),
 ('speaking', 'O'), ('at', 'O'), ('the', 'O'),
 ('White', 'LOCATION'), ('House', 'LOCATION'), ('.', 'O')]
>>> print(tagger.get_entities(sent))
{'Person': ['Obama'], 'LOCATION': ['White House']}

Reference

This library uses bidirectional LSTM + CRF model based on Neural Architectures for Named Entity Recognition by Lample, Guillaume, et al., NAACL 2016.