理解Keras二进制分类任务中过度拟合的原因

时间:2017-06-28 22:01:04

标签: python tensorflow deep-learning keras

我正在对IMDB电影评论数据进行二元分类,将其分为正面或负面情绪。

我有25K电影评论和相应的标签。

预处理:

删除停用词并将数据分成70:30训练和测试。所以17.5K训练和7k测试。 17.5k训练进一步分为keK.model.fit方法中使用的14K训练和3.5k验证数据集

使用Keras文本处理模块将每个已处理的电影评论转换为TF-IDF向量。

这是我在Keras Dense类中使用的完全连接架构

def model_param(self): 
    """ Method to do deep learning

    """

    from keras.models import Sequential
    from keras.layers import Dense, Dropout, Activation
    from keras.optimizers import SGD
    from keras import regularizers

    self.model = Sequential()
    # Dense(64) is a fully-connected layer with 64 hidden units.
    # in the first layer, you must specify the expected input data shape:
    # here, 20-dimensional vectors.
    self.model.add(Dense(32, activation='relu', input_dim=self.x_train_std.shape[1]))
    self.model.add(Dropout(0.5))
    #self.model.add(Dense(60, activation='relu'))
    #self.model.add(Dropout(0.5))
    self.model.add(Dense(1, activation='sigmoid'))

    sgd = SGD(lr=0.01, decay=1e-6, momentum=0.9, nesterov=True)
    self.model.compile(loss='binary_crossentropy',
          optimizer=sgd,
          metrics=['accuracy'])



def fit(self):
    """ Training the deep learning network on the training data

    """

    self.model.fit(self.x_train_std, self.y_train,validation_split=0.20,
      epochs=50,
      batch_size=128)

如你所见,我首先尝试没有Dropout,像往常一样,我的训练准确度为1.0,但验证很差,因为过度拟合正在发生。所以我添加了Dropout以防止过度拟合

然而,尽管尝试多次辍学率,但添加另一层不同的数量。其中的单位,改变学习率我仍然对验证数据集过度拟合。停留在85%,而训练持续增加到99%等等。甚至将时代从10改为50

这里可能出现的问题

Train on 14000 samples, validate on 3500 samples
Epoch 1/50
14000/14000 [==============================] - 0s - loss: 0.5684 - acc: 0.7034 - val_loss: 0.3794 - val_acc: 0.8431
Epoch 2/50
14000/14000 [==============================] - 0s - loss: 0.3630 - acc: 0.8388 - val_loss: 0.3304 - val_acc: 0.8549
Epoch 3/50
14000/14000 [==============================] - 0s - loss: 0.2977 - acc: 0.8749 - val_loss: 0.3271 - val_acc: 0.8591
Epoch 4/50
14000/14000 [==============================] - 0s - loss: 0.2490 - acc: 0.8991 - val_loss: 0.3302 - val_acc: 0.8580
Epoch 5/50
14000/14000 [==============================] - 0s - loss: 0.2251 - acc: 0.9086 - val_loss: 0.3388 - val_acc: 0.8546
Epoch 6/50
14000/14000 [==============================] - 0s - loss: 0.2021 - acc: 0.9189 - val_loss: 0.3532 - val_acc: 0.8523
Epoch 7/50
14000/14000 [==============================] - 0s - loss: 0.1797 - acc: 0.9286 - val_loss: 0.3670 - val_acc: 0.8529
Epoch 8/50
14000/14000 [==============================] - 0s - loss: 0.1611 - acc: 0.9350 - val_loss: 0.3860 - val_acc: 0.8543
Epoch 9/50
14000/14000 [==============================] - 0s - loss: 0.1427 - acc: 0.9437 - val_loss: 0.4077 - val_acc: 0.8529
Epoch 10/50
14000/14000 [==============================] - 0s - loss: 0.1344 - acc: 0.9476 - val_loss: 0.4234 - val_acc: 0.8526
Epoch 11/50
14000/14000 [==============================] - 0s - loss: 0.1222 - acc: 0.9534 - val_loss: 0.4473 - val_acc: 0.8506
Epoch 12/50
14000/14000 [==============================] - 0s - loss: 0.1131 - acc: 0.9546 - val_loss: 0.4718 - val_acc: 0.8497
Epoch 13/50
14000/14000 [==============================] - 0s - loss: 0.1079 - acc: 0.9559 - val_loss: 0.4818 - val_acc: 0.8526
Epoch 14/50
14000/14000 [==============================] - 0s - loss: 0.0954 - acc: 0.9630 - val_loss: 0.5057 - val_acc: 0.8494
Epoch 15/50
14000/14000 [==============================] - 0s - loss: 0.0906 - acc: 0.9636 - val_loss: 0.5229 - val_acc: 0.8557
Epoch 16/50
14000/14000 [==============================] - 0s - loss: 0.0896 - acc: 0.9657 - val_loss: 0.5387 - val_acc: 0.8497
Epoch 17/50
14000/14000 [==============================] - 0s - loss: 0.0816 - acc: 0.9666 - val_loss: 0.5579 - val_acc: 0.8463
Epoch 18/50
14000/14000 [==============================] - 0s - loss: 0.0762 - acc: 0.9709 - val_loss: 0.5704 - val_acc: 0.8491
Epoch 19/50
14000/14000 [==============================] - 0s - loss: 0.0718 - acc: 0.9723 - val_loss: 0.5834 - val_acc: 0.8454
Epoch 20/50
14000/14000 [==============================] - 0s - loss: 0.0633 - acc: 0.9752 - val_loss: 0.6032 - val_acc: 0.8494
Epoch 21/50
14000/14000 [==============================] - 0s - loss: 0.0687 - acc: 0.9724 - val_loss: 0.6181 - val_acc: 0.8480
Epoch 22/50
14000/14000 [==============================] - 0s - loss: 0.0614 - acc: 0.9762 - val_loss: 0.6280 - val_acc: 0.8503
Epoch 23/50
14000/14000 [==============================] - 0s - loss: 0.0620 - acc: 0.9756 - val_loss: 0.6407 - val_acc: 0.8500
Epoch 24/50
14000/14000 [==============================] - 0s - loss: 0.0536 - acc: 0.9794 - val_loss: 0.6563 - val_acc: 0.8511
Epoch 25/50
14000/14000 [==============================] - 0s - loss: 0.0538 - acc: 0.9791 - val_loss: 0.6709 - val_acc: 0.8500
Epoch 26/50
14000/14000 [==============================] - 0s - loss: 0.0507 - acc: 0.9807 - val_loss: 0.6869 - val_acc: 0.8491
Epoch 27/50
14000/14000 [==============================] - 0s - loss: 0.0528 - acc: 0.9794 - val_loss: 0.7002 - val_acc: 0.8483
Epoch 28/50
14000/14000 [==============================] - 0s - loss: 0.0465 - acc: 0.9810 - val_loss: 0.7083 - val_acc: 0.8469
Epoch 29/50
14000/14000 [==============================] - 0s - loss: 0.0504 - acc: 0.9796 - val_loss: 0.7153 - val_acc: 0.8497
Epoch 30/50
14000/14000 [==============================] - 0s - loss: 0.0477 - acc: 0.9819 - val_loss: 0.7232 - val_acc: 0.8480
Epoch 31/50
14000/14000 [==============================] - 0s - loss: 0.0475 - acc: 0.9819 - val_loss: 0.7343 - val_acc: 0.8469
Epoch 32/50
14000/14000 [==============================] - 0s - loss: 0.0459 - acc: 0.9819 - val_loss: 0.7352 - val_acc: 0.8500
Epoch 33/50
14000/14000 [==============================] - 0s - loss: 0.0426 - acc: 0.9807 - val_loss: 0.7429 - val_acc: 0.8511
Epoch 34/50
14000/14000 [==============================] - 0s - loss: 0.0396 - acc: 0.9846 - val_loss: 0.7576 - val_acc: 0.8477
Epoch 35/50
14000/14000 [==============================] - 0s - loss: 0.0420 - acc: 0.9836 - val_loss: 0.7603 - val_acc: 0.8506
Epoch 36/50
14000/14000 [==============================] - 0s - loss: 0.0359 - acc: 0.9856 - val_loss: 0.7683 - val_acc: 0.8497
Epoch 37/50
14000/14000 [==============================] - 0s - loss: 0.0377 - acc: 0.9849 - val_loss: 0.7823 - val_acc: 0.8520
Epoch 38/50
14000/14000 [==============================] - 0s - loss: 0.0352 - acc: 0.9861 - val_loss: 0.7912 - val_acc: 0.8500
Epoch 39/50
14000/14000 [==============================] - 0s - loss: 0.0390 - acc: 0.9845 - val_loss: 0.8025 - val_acc: 0.8489
Epoch 40/50
14000/14000 [==============================] - 0s - loss: 0.0371 - acc: 0.9853 - val_loss: 0.8128 - val_acc: 0.8494
Epoch 41/50
14000/14000 [==============================] - 0s - loss: 0.0367 - acc: 0.9848 - val_loss: 0.8184 - val_acc: 0.8503
Epoch 42/50
14000/14000 [==============================] - 0s - loss: 0.0331 - acc: 0.9871 - val_loss: 0.8264 - val_acc: 0.8500
Epoch 43/50
14000/14000 [==============================] - 0s - loss: 0.0338 - acc: 0.9871 - val_loss: 0.8332 - val_acc: 0.8483
Epoch 44/50

0 个答案:

没有答案