我正在研究基于 LSTM 的 Encoder-Decoder 拼写校正模型,该模型提供了 4600000 行的训练数据。训练文件由两列组成 - 正确和不正确的句子。
当数据小到 200000 时,模型运行良好。但是当我增加它时,训练不会超过 2 个时期。它有时会给出 terminate called after throwing an instance of std::bad_alloc
的错误,有时训练停止而没有任何错误或警告。
我尝试使用它,但没有用。也许我用错了。
keras.clear_session()
我也尝试将latent_dim 和batch_size 的值降低到128,64,32,16,8,4,1,但它们都不适用于如此大的数据。 另外由于数据量很大所以我替换了
的值steps_per_epoch = train_samples//batch_size
到
steps_per_epoch = 2000
我清除了缓存以释放内存,但训练仍未完成。有人可以建议一种方法来训练我的模型吗?
def generate_batch(X = X_train, y = y_train, batch_size = 128):
# Generate a batch of data
while True:
for j in range(0, len(X), batch_size):
encoder_input_data = np.zeros((batch_size, max_length_src),dtype='float32')
decoder_input_data = np.zeros((batch_size, max_length_tar),dtype='float32')
decoder_target_data = np.zeros((batch_size, max_length_tar, num_decoder_tokens),dtype='float32')
for i, (input_text, target_text) in enumerate(zip(X[j:j+batch_size], y[j:j+batch_size])):
for t, word in enumerate(input_text.split()):
encoder_input_data[i, t] = input_token_index[word] # encoder input seq
for t, word in enumerate(target_text.split()):
if t<len(target_text.split())-1:
decoder_input_data[i, t] = target_token_index[word] # decoder input seq
if t>0:
# decoder target sequence (one hot encoded)
# does not include the START_ token
# Offset by one timestep
decoder_target_data[i, t - 1, target_token_index[word]] = 1.
yield([encoder_input_data, decoder_input_data], decoder_target_data)
latent_dim = 50
# Encoder
encoder_inputs = Input(shape=(None,))
enc_emb = Embedding(num_encoder_tokens+1, latent_dim, mask_zero = True)(encoder_inputs)
encoder_lstm = LSTM(latent_dim, return_state=True)
encoder_outputs, state_h, state_c = encoder_lstm(enc_emb)
# We discard `encoder_outputs` and only keep the states.
encoder_states = [state_h, state_c]
# Set up the decoder, using `encoder_states` as initial state.
decoder_inputs = Input(shape=(None,))
dec_emb_layer = Embedding(num_decoder_tokens, latent_dim, mask_zero = True)
dec_emb = dec_emb_layer(decoder_inputs)
# We set up our decoder to return full output sequences,
# and to return internal states as well. We don't use the
# return states in the training model, but we will use them in inference.
decoder_lstm = LSTM(latent_dim, return_sequences=True, return_state=True)
decoder_outputs, _, _ = decoder_lstm(dec_emb,
initial_state=encoder_states)
decoder_dense = Dense(num_decoder_tokens, activation='softmax')
decoder_outputs = decoder_dense(decoder_outputs)
# Define the model that will turn
# `encoder_input_data` & `decoder_input_data` into `decoder_target_data`
model = Model([encoder_inputs, decoder_inputs], decoder_outputs)
model.compile(optimizer='rmsprop', loss='categorical_crossentropy', metrics=['accuracy'])
train_samples = len(X_train)
val_samples = len(X_test)
batch_size = 128
epochs = 50
from tensorflow.keras.callbacks import EarlyStopping, ModelCheckpoint
from keras.layers import Conv2D, MaxPooling2D
from keras import backend as K
from keras.callbacks import ModelCheckpoint
keras_callbacks = [
EarlyStopping(monitor ="val_loss", mode ="min", patience = 5, restore_best_weights = True),
ModelCheckpoint('checkpoints.hdf5', monitor='val_loss', verbose=1, save_best_only=True, mode='min', save_freq=1)
]
model.fit_generator(generator = generate_batch(X_train, y_train, batch_size = batch_size),
#steps_per_epoch = train_samples//batch_size,
steps_per_epoch = 2000,
epochs=epochs,
verbose=1,
validation_data = generate_batch(X_test, y_test, batch_size = batch_size),
validation_steps = val_samples//batch_size,
callbacks=keras_callbacks)
model.save_weights('weights.h5')
答案 0 :(得分:0)
发生内存错误是因为您在 input_token_index
函数中使用了“大”全局范围变量 generate_batch
。此变量将在内存中多次复制以生成数据。
然而,与其解决这个特定问题,我建议您使用原生 TF 功能进行文本标记化、矢量化和批处理,而不是编写自己的实现。
您可以在此处找到有关文本标记化和矢量化的更多信息 - official Tensorflow tutorial)。具体来说,您可以利用 Tensorflow text vectorisation 功能,它结合了标记化和填充。或者,您可以使用更成熟的 Tokeniser 和一般的 pad_sequences
创建批次是 SGD
类型训练的超级基本和通用任务,因此不要重新发明轮子,只需使用 model.fit
,它会自动免费对您的数据进行批处理。