Source code for asreview.models.classifiers.lstm_base

# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

import logging

    import tensorflow as tf
    from tensorflow.keras import optimizers
    from tensorflow.keras.layers import Dense
    from tensorflow.keras.layers import Embedding
    from tensorflow.keras.layers import LSTM
    from tensorflow.keras.models import Sequential
    from tensorflow.keras.wrappers.scikit_learn import KerasClassifier
except ImportError:
    TF_AVAILABLE = False
    except AttributeError:

from asreview.models.classifiers.base import BaseTrainClassifier
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 LSTMBaseClassifier(BaseTrainClassifier): """LSTM base classifier. LSTM model that consists of an embedding layer, LSTM layer with one output, dense 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. learn_rate: float Learn rate multiplier of default learning rate. dense_width: int Size of the dense layer of the model. 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-base" def __init__(self, embedding_matrix=None, backwards=True, dropout=0.4, optimizer="rmsprop", lstm_out_width=20, learn_rate=1.0, dense_width=128, verbose=0, batch_size=32, epochs=35, shuffle=False, class_weight=30.0): """Initialize the LSTM base model""" super(LSTMBaseClassifier, 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.dense_width = dense_width self.verbose = verbose self.batch_size = batch_size self.epochs = epochs self.shuffle = shuffle self.class_weight = class_weight 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_base_model( embedding_matrix=self.embedding_matrix, backwards=self.backwards, dropout=self.dropout, optimizer=self.optimizer, max_sequence_length=self.sequence_length, lstm_out_width=self.lstm_out_width, dense_width=self.dense_width, learn_rate=self.learn_rate, verbose=self.verbose) print(keras_model) self._model = KerasClassifier(keras_model, verbose=self.verbose) X, y, batch_size=self.batch_size, epochs=self.epochs, shuffle=self.shuffle, class_weight=_set_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(LSTMBaseClassifier, self).default_param defaults.pop("embedding_matrix") return defaults
def _create_lstm_base_model(embedding_matrix, backwards=True, dropout=0.4, optimizer='rmsprop', max_sequence_length=1000, lstm_out_width=20, dense_width=128, 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() 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, )) # add Dense layer with relu activation model.add(Dense( dense_width, activation='relu', )) # add Dense 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(verbose=verbose) return model return model_wrapper def _get_optimizer(optimizer, lr_mult=1.0): "Get optimizer with correct learning rate." if optimizer == "sgd": return optimizers.SGD(lr=0.01 * lr_mult) elif optimizer == "rmsprop": return optimizers.RMSprop(lr=0.001 * lr_mult) elif optimizer == "adagrad": return optimizers.Adagrad(lr=0.01 * lr_mult) elif optimizer == "adam": return optimizers.Adam(lr=0.001 * lr_mult) elif optimizer == "nadam": return optimizers.Nadam(lr=0.002 * lr_mult) raise NotImplementedError