머신러닝스터디/2016/2016 07 09

2016-07-13T05:23:46Z

114.108.98.54:

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== 내용 ==
* Embedding에는 word index가 필요함.
** 초기에 Tokenizer로 word frequency를 input으로 썼는데 학습이 잘 안됨.
** [http://keras.io/layers/embeddings/]
tokenizer = Tokenizer(nb_words=1000)
X_train = tokenizer.sequences_to_matrix(X_train, mode="freq")

* optimizer
** adamax 를 썼는데 accuracy가 50% 대에 머무름
** tensorflow는 adamax를 제공하지 않음. keras 자체 구현됨([https://github.com/fchollet/keras/blob/c30432a665e23d598d2cec11094b0cc3cac2f46d/keras/optimizers.py#L356 code]).

* 적절한 batch size
** batch size가 너무 작으면(e.g. 32) 학습이 오래 걸린다.
** 반면 너무 크면 메모리를 많이 사용하게 된다.
=== 코드 ===
import keras
import numpy as np
from keras.datasets import imdb
from keras.preprocessing.text import Tokenizer
from keras.models import Sequential
from keras.layers import Dense, Dropout, Embedding, LSTM

(X_train, y_train), (X_test, y_test) = imdb.load_data(nb_words=1000)

from keras.preprocessing.sequence import pad_sequences
X_train = pad_sequences(X_train, 1000)
X_test = pad_sequences(X_test, 1000)

model = Sequential()
model.add(Embedding(1000, 64, input_length=1000))
model.add(LSTM(output_dim=32, activation='sigmoid', inner_activation='hard_sigmoid'))
model.add(Dense(16, activation="relu"))
model.add(Dropout(0.5))
model.add(Dense(8, activation="relu"))
model.add(Dropout(0.5))
model.add(Dense(1, activation="sigmoid"))

model.compile(loss="binary_crossentropy", optimizer="adagrad", metrics=["accuracy"])

model.fit(X_train, y_train, batch_size=500, nb_epoch=100)
model.evaluate(X_test, y_test, batch_size=1000)
pred = model.predict(X_test, batch_size=20000)

print (pred[0], y_test[0])
print (pred[1], y_test[1])
print (pred[2], y_test[2])

=== Padding ===
pad_sequences은 배열의 길이가 다를 때 특정값을 채워넣어 길이를 맞춘다.
X_train = pad_sequences(X_train, 1000)
위의 코드는 X_train의 인풋 배열중 1000보다 길이가 짧은 배열에 0을 채워넣는다.
그러나 1000보다 더 긴 배열을 줄여주진 않는다.
(X_train, y_train), (X_test, y_test) = imdb.load_data(nb_words=1000)
다음과 같이 input length가 될 단어 인덱스 길이를 1000으로 제한해야 한다.

결과 예시
array([ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 20, 28, 716, 48, 495, 79, 27, 493, 8, 2,
7, 50, 5, 2, 2, 10, 5, 852, 157, 11, 5, 2, 2,
10, 5, 500, 2, 6, 33, 256, 41, 2, 7, 17, 23, 48,
2, 2, 26, 269, 929, 18, 2, 7, 2, 2, 8, 105, 5,
2, 182, 314, 38, 98, 103, 7, 36, 2, 246, 360, 7, 19,
396, 17, 26, 269, 929, 18, 2, 493, 6, 116, 7, 105, 5,
575, 182, 27, 5, 2, 2, 130, 62, 17, 24, 89, 17, 13,
381, 2, 8, 2, 7, 5, 2, 38, 325, 7, 17, 23, 93,
9, 156, 252, 19, 235, 20, 28, 5, 104, 76, 7, 17, 169,
35, 2, 17, 23, 2, 7, 36, 2, 934, 56, 2, 6, 17,
891, 214, 11, 5, 2, 6, 92, 6, 33, 256, 82, 7], dtype=int32)

nb_words로 배열의 최대 길이를 지정하지 않으면 Embedding 단계에서 out of index 에러가 난다.
IndexError: index 4414 is out of bounds for size 1000

=== 학습 실패 ===
Using Theano backend.
Epoch 1/10
22500/22500 [==============================] - 115s - loss: 0.6932 - acc: 0.5014
Epoch 2/10
22500/22500 [==============================] - 115s - loss: 0.6932 - acc: 0.5010
Epoch 3/10
22500/22500 [==============================] - 114s - loss: 0.6932 - acc: 0.5014
Epoch 4/10
22500/22500 [==============================] - 115s - loss: 0.6931 - acc: 0.5014
Epoch 5/10
22500/22500 [==============================] - 115s - loss: 0.6931 - acc: 0.5014
Epoch 6/10
22500/22500 [==============================] - 115s - loss: 0.6932 - acc: 0.5014
Epoch 7/10
22500/22500 [==============================] - 114s - loss: 0.6931 - acc: 0.5014
Epoch 8/10
22500/22500 [==============================] - 114s - loss: 0.6932 - acc: 0.5016
Epoch 9/10
22500/22500 [==============================] - 115s - loss: 0.6932 - acc: 0.5014
Epoch 10/10
22500/22500 [==============================] - 115s - loss: 0.6932 - acc: 0.5014

=== 학습 성공 ===
Epoch 1/10
22500/22500 [==============================] - 14282s - loss: 0.6927 - acc: 0.5164
Epoch 2/10
22500/22500 [==============================] - 10235s - loss: 0.6864 - acc: 0.5618
Epoch 3/10
22500/22500 [==============================] - 3236s - loss: 0.6541 - acc: 0.6508
Epoch 4/10
22500/22500 [==============================] - 3230s - loss: 0.5829 - acc: 0.7528
Epoch 5/10
22500/22500 [==============================] - 3222s - loss: 0.5490 - acc: 0.7745
Epoch 6/10
22500/22500 [==============================] - 3229s - loss: 0.5250 - acc: 0.7946
Epoch 7/10
22500/22500 [==============================] - 3230s - loss: 0.5052 - acc: 0.8030
Epoch 8/10
22300/22500 [============================>.] - ETA: 28s - loss: 0.4963 - acc: 0.8046
(사실 다음날 보니 프로세스가 죽어있어서 Epoch 8/10 이후의 결과는 없음...)
== 다음 시간에는 ==
* Coursera 동영상 week 7 보기
== 더 보기 ==

ZeroWiki - User contributions [en]

머신러닝스터디/2016/2016 07 09