[英]Dropout entire input layer
假設我有兩個輸入(每個輸入都有許多功能),我想將它們輸入到Dropout
層中。 我希望每次迭代都刪除整個輸入及其所有相關功能,並保留所有其他輸入。
連接輸入之后,我認為我需要對Dropout
使用noise_shape
參數,但是連接層的形狀實際上並不能讓我這樣做。 對於形狀(15,)的兩個輸入,連接的形狀是(None,30),而不是(None,15,2),所以其中一個軸丟失了,我無法沿着它掉落。
有什么建議我可以做什么? 謝謝。
from keras.layers import Input, concatenate, Dense, Dropout
x = Input((15,)) # 15 features for the 1st input
y = Input((15,)) # 15 features for the 2nd input
xy = concatenate([x, y])
print(xy._keras_shape)
# (None, 30)
layer = Dropout(rate=0.5, noise_shape=[xy.shape[0], 1])(xy)
...
編輯:
好像我誤解了您的問題,這是根據您的要求更新的答案。
為了實現您想要的效果,x和y有效地成為了時間步長,根據noise_shape=(batch_size, 1, features)
文檔,如果您輸入的形狀為(batch_size, timesteps, features)
,則noise_shape=(batch_size, 1, features)
(batch_size, timesteps, features)
:
x = Input((15,1)) # 15 features for the 1st input
y = Input((15,1)) # 15 features for the 2nd input
xy = concatenate([x, y])
dropout_layer = Dropout(rate=0.5, noise_shape=[None, 1, 2])(xy)
...
要測試您是否獲得正確的行為,可以使用以下代碼( 參考鏈接 )檢查中間xy
層和dropout_layer
:
### Define your model ###
from keras.layers import Input, concatenate, Dropout
from keras.models import Model
from keras import backend as K
# Learning phase must be set to 1 for dropout to work
K.set_learning_phase(1)
x = Input((15,1)) # 15 features for the 1st input
y = Input((15,1)) # 15 features for the 2nd input
xy = concatenate([x, y])
dropout_layer = Dropout(rate=0.5, noise_shape=[None, 1, 2])(xy)
model = Model(inputs=[x,y], output=dropout_layer)
# specify inputs and output of the model
x_inp = model.input[0]
y_inp = model.input[1]
outp = [layer.output for layer in model.layers[2:]]
functor = K.function([x_inp, y_inp], outp)
### Get some random inputs ###
import numpy as np
input_1 = np.random.random((1,15,1))
input_2 = np.random.random((1,15,1))
layer_outs = functor([input_1,input_2])
print('Intermediate xy layer:\n\n',layer_outs[0])
print('Dropout layer:\n\n', layer_outs[1])
您應該看到,根據您的要求,整個x或y被隨機丟棄(機會為50%):
Intermediate xy layer:
[[[0.32093528 0.70682645]
[0.46162075 0.74063486]
[0.522718 0.22318116]
[0.7897043 0.7849486 ]
[0.49387926 0.13929296]
[0.5754296 0.6273373 ]
[0.17157765 0.92996144]
[0.36210892 0.02305864]
[0.52637625 0.88259524]
[0.3184462 0.00197006]
[0.67196816 0.40147918]
[0.24782693 0.5766827 ]
[0.25653633 0.00514544]
[0.8130438 0.2764429 ]
[0.25275478 0.44348967]]]
Dropout layer:
[[[0. 1.4136529 ]
[0. 1.4812697 ]
[0. 0.44636232]
[0. 1.5698972 ]
[0. 0.2785859 ]
[0. 1.2546746 ]
[0. 1.8599229 ]
[0. 0.04611728]
[0. 1.7651905 ]
[0. 0.00394012]
[0. 0.80295837]
[0. 1.1533654 ]
[0. 0.01029088]
[0. 0.5528858 ]
[0. 0.88697934]]]
如果你想知道為什么所有的元素都乘以2,看看tensorflow如何實現輟學這里 。
希望這可以幫助。
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