Source code for asreview.models.classifiers.lstm_pool

# Copyright 2019-2020 The ASReview Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import logging

try:
    import tensorflow as tf
    from tensorflow.keras.constraints import MaxNorm
    from tensorflow.keras.layers import Dense
    from tensorflow.keras.layers import Embedding
    from tensorflow.keras.layers import Flatten
    from tensorflow.keras.layers import LSTM
    from tensorflow.keras.layers import MaxPooling1D
    from tensorflow.keras.models import Sequential
    from tensorflow.keras.wrappers.scikit_learn import KerasClassifier
except ImportError:
    TF_AVAILABLE = False
else:
    TF_AVAILABLE = True
    try:
        tf.logging.set_verbosity(tf.logging.ERROR)
    except AttributeError:
        logging.getLogger("tensorflow").setLevel(logging.ERROR)

from asreview.models.classifiers.base import BaseTrainClassifier
from asreview.models.classifiers.lstm_base import _get_optimizer
from asreview.utils import _set_class_weight


def _check_tensorflow():
    if not TF_AVAILABLE:
        raise ImportError(
            "Install tensorflow package (`pip install tensorflow`) to use"
            " 'EmbeddingIdf'.")


[docs]class LSTMPoolClassifier(BaseTrainClassifier): """ LSTM pool classifier. LSTM model that consists of an embedding layer, LSTM layer with many outputs, max pooling layer, and a single sigmoid output node. Use the :class:`asreview.models.feature_extraction.EmbeddingLSTM` feature extraction method. Currently not so well optimized and slow. .. note:: This model requires ``tensorflow`` to be installed. Use ``pip install tensorflow`` or install all optional ASReview dependencies with ``pip install asreview[all]`` Arguments --------- embedding_matrix: numpy.ndarray Embedding matrix to use with LSTM model. backwards: bool Whether to have a forward or backward LSTM. dropout: float Value in [0, 1.0) that gives the dropout and recurrent dropout rate for the LSTM model. optimizer: str Optimizer to use. lstm_out_width: int Output width of the LSTM. lstm_pool_size: int Size of the pool, must be a divisor of max_sequence_length. learn_rate: float Learn rate multiplier of default learning rate. verbose: int Verbosity. batch_size: int Size of the batch size for the LSTM model. epochs: int Number of epochs to train the LSTM model. shuffle: bool Whether to shuffle the data before starting to train. class_weight: float Class weight for the included papers. """ name = "lstm-pool" def __init__(self, embedding_matrix=None, backwards=True, dropout=0.4, optimizer="rmsprop", lstm_out_width=20, lstm_pool_size=128, learn_rate=1.0, verbose=0, batch_size=32, epochs=35, shuffle=False, class_weight=30.0): """Initialize the LSTM pool model.""" super(LSTMPoolClassifier, self).__init__() self.embedding_matrix = embedding_matrix self.backwards = backwards self.dropout = dropout self.optimizer = optimizer self.lstm_out_width = lstm_out_width self.learn_rate = learn_rate self.verbose = verbose self.batch_size = batch_size self.epochs = epochs self.shuffle = shuffle self.class_weight = _set_class_weight(class_weight) self.lstm_pool_size = lstm_pool_size self._model = None self.sequence_length = None
[docs] def fit(self, X, y): # check is tensorflow is available _check_tensorflow() sequence_length = X.shape[1] if self._model is None or sequence_length != self.sequence_length: self.sequence_length = sequence_length keras_model = _create_lstm_pool_model( embedding_matrix=self.embedding_matrix, backwards=self.backwards, dropout=self.dropout, optimizer=self.optimizer, max_sequence_length=sequence_length, lstm_out_width=self.lstm_out_width, learn_rate=self.learn_rate, verbose=self.verbose) self._model = KerasClassifier(keras_model, verbose=self.verbose) self._model.fit( X, y, batch_size=self.batch_size, epochs=self.epochs, shuffle=self.shuffle, class_weight=self.class_weight, verbose=self.verbose)
[docs] def full_hyper_space(self): from hyperopt import hp hyper_choices = {} hyper_space = { "mdl_dropout": hp.uniform("mdl_dropout", 0, 0.9), "mdl_lstm_out_width": hp.quniform("mdl_lstm_out_width", 1, 50, 1), "mdl_dense_width": hp.quniform("mdl_dense_width", 1, 200, 1), "mdl_learn_rate_mult": hp.lognormal("mdl_learn_rate_mult", 0, 1) } return hyper_space, hyper_choices
@property def default_param(self): defaults = super(LSTMPoolClassifier, self).default_param defaults.pop("embedding_matrix") return defaults
def _create_lstm_pool_model(embedding_matrix, backwards=True, dropout=0.4, optimizer='rmsprop', max_sequence_length=1000, lstm_out_width=20, lstm_pool_size=100, learn_rate=1.0, verbose=1): """Return callable lstm model. Returns ------- callable: A function that return the Keras Sklearn model when called. """ # check is tensorflow is available _check_tensorflow() # The Sklearn API requires a callable as result. # https://keras.io/scikit-learn-api/ def model_wrapper(): model = Sequential() # add first embedding layer with pretrained wikipedia weights model.add( Embedding( embedding_matrix.shape[0], embedding_matrix.shape[1], weights=[embedding_matrix], input_length=max_sequence_length, trainable=False)) # add LSTM layer model.add( LSTM( lstm_out_width, input_shape=(max_sequence_length, ), go_backwards=backwards, dropout=dropout, recurrent_dropout=dropout, return_sequences=True, kernel_constraint=MaxNorm(), )) model.add(MaxPooling1D(pool_size=lstm_pool_size, )) model.add(Flatten()) # Add output layer model.add(Dense(1, activation='sigmoid')) optimizer_fn = _get_optimizer(optimizer, learn_rate) # Compile model model.compile( loss='binary_crossentropy', optimizer=optimizer_fn, metrics=['acc']) if verbose >= 1: model.summary() return model return model_wrapper