How can I get hidden layer representation of the given data?

[erogol]

After training I want to extract the hidden layer representation of the given data instead of the final probabilities. How can I do it with Keras?

[fchollet]

One simple way to do it is to use the weights of your model to build a new model that's truncated at the layer you want to read. Then you can run the ._predict(X_batch) method to get the activations for a batch of inputs.

Example:

# this is your initial model
model = Sequential()
model.add(Dense(20, 64, init='uniform'))
model.add(Activation('tanh'))
model.add(Dense(64, 1, init='uniform'))
model.add(Activation('softmax'))

# we train it
model.compile(loss='mse', optimizer='sgd')
model.fit(X_train, y_train, nb_epoch=20, batch_size=16)

# we build a new model with the activations of the old model
# this model is truncated after the first layer
model2 = Sequential()
model2.add(Dense(20, 64, weights=model.layers[0].get_weights()))
model2.add(Activation('tanh'))

activations = model2._predict(X_batch)

Note: I haven't tested it.

Another way to do it would be to define a Theano function to get the layer's output:

import theano
get_activations = theano.function([model.layers[0].input], model.layers[1].output(train=False), allow_input_downcast=True)
activations = get_activations(X_batch) # same result as above

Note: also untested.

[erogol]

Thanks... :)

[xypan1232]

Hi,

I try to use activations = model2._predict(X_batch), but it seems there is no _predict function, is this a bug? Thanks.

File "/usr/local/lib/python2.7/dist-packages/Keras-0.1.2-py2.7.egg/keras/models.py", line 469, in predict return self._predict_loop(self._predict, X, batch_size, verbose)[0] AttributeError: 'Sequential' object has no attribute '_predict'

[fchollet]

You need to compile your model first.

On 2 September 2015 at 12:17, xypan1232 notifications@github.com wrote:

Hi,

I try to use activations = model2._predict(X_batch), but it seems there is no _predict function, is this a bug? Thanks.

File "/usr/local/lib/python2.7/dist-packages/Keras-0.1.2-py2.7.egg/keras/models.py", line 469, in predict return self._predict_loop(self._predict, X, batch_size, verbose)[0] AttributeError: 'Sequential' object has no attribute '_predict'

— Reply to this email directly or view it on GitHub https://github.com/fchollet/keras/issues/41#issuecomment-137218101.

[damaha]

I create the theano function to get the activations, that's easy. A function to get activations from any model at any layer can very easily be defined:

def get_activations(model, layer, X_batch):
    get_activations = theano.function([model.layers[0].input], model.layers[layer].get_output(train=False), allow_input_downcast=True)
    activations = get_activations(X_batch) # same result as above
    return activations

but it seems like there is no attribute called 'output' of any layers so I guess it is the 'get_output()' method that is supposed to be used. That works for me at least.

[hemanth2090]

@damaha I am trying to get the weights of the hidden layers in a graph model. I used the function you have defined above. I got an error saying -- AttributeError: 'Graph' object has no attribute 'layers'

get_output() does not give the required output when using a graph model. Can you please share a code snippet of your implementation?

@fchollet Can you also please help. I am looking to save the weights so that I can create the image after the convolutions. I used model.save_weights to save a hdf5 file. But I am unable to convert that into a numpy array and save it as an image.

[lemuriandezapada]

graph layers are called nodes

[havaeimo]

I have a CNN model where I do the softmax across channels. (Ive made a costum activation function and pass it to convolutional2D to do this).

graph = Graph()
graph.add_input(name='input',input_shape=(img_channels, img_rows, img_cols))
graph.add_node(Convolution2D(16, 3, 3, border_mode='valid'),name='conv_1',input='input')
graph.add_node(Activation('relu'),name='rlu_1',input='conv_1')
graph.add_node(Convolution2D(nb_classes, 22, 22,activation=across_channel_softmax, border_mode='valid'), name='conv_2', input='rlu_1')  # By doing this convolutional operation the shape of the featuremaps will be (nb_classes,1,1)
graph.add_node(Flatten(), name='flatten', input='conv_2')
graph.add_output(name='output',input='flatten')

Now to get outputs from my across_channel_softmax layer i define a theano function

get_activations = theano.function([graph.inputs['input'].input], graph.nodes['conv_2'].get_output(train=False), allow_input_downcast=True)
    results = get_activations(data) 

It works if data has the same shape (i.e. i.e same rows and cols) as the training data. But im under the assumption that in the theano function "get_activations" there is nothing to restrict the input shape and so I should be able to give it a larger image size and the output would scale accordingly. However when I do so I get the following error. Note that if i wanted to get the outputs of 'conv_1', the same way it works, but thats not what im interested in

ValueError: Dimension 2 in Rebroadcast's input was supposed to be 1 (got 11 instead)
Apply node that caused the error: Rebroadcast{?,?,1,1}(GpuDimShuffle{1,0,2,3}.0)
Toposort index: 44
Inputs types: [CudaNdarrayType(float32, 4D)]
Inputs shapes: [(288, 5, 11, 11)]
Inputs strides: [(231, 66528, 11, 1)]
Inputs values: ['not shown']
Outputs clients: [[GpuElemwise{Add}[(0, 0)](Rebroadcast{?,?,1,1}.0, GpuDimShuffle{x,0,x,x}.0)]]

[justdark]

@damaha your function have some problem when I use a Merge layer as the first Layer of model, How could I solve it?

[justdark]

I see, I should pass the variable to the origin Sequence before it merged.

[magic282]

I have a Graph model and tried to get the output of the hidden layers using the method from the Keras FAQ

(feature1, feature2, feature3) = self.feature_to_nparray(feature)
feature1= np.array([feature1])
feature2= np.array([feature2])
feature3= np.array([feature3])
data = {'f1': feature1, 'f2': feature2, 'f3': feature3}
get_h1_output = theano.function([self.model.inputs[i].input for i in self.model.input_order],
                           self.model.nodes['h1'].get_output(train=False),
                           on_unused_input='ignore', allow_input_downcast=True)
get_softmax_output = theano.function([self.model.inputs[i].input for i in self.model.input_order],
                                    self.model.nodes['softmax'].get_output(train=False),
                                    on_unused_input='ignore', allow_input_downcast=True)
h1_output = get_h1_output(data)
softmax_output = get_softmax_output(data)

But I got the following error:

...
  File "C:\Anaconda\lib\site-packages\theano-0.7.0-py2.7.egg\theano\compile\function_module.py", line 786, in __call__
    allow_downcast=s.allow_downcast)
  File "C:\Anaconda\lib\site-packages\theano-0.7.0-py2.7.egg\theano\tensor\type.py", line 116, in filter
    data = theano._asarray(data, dtype=self.dtype)
  File "C:\Anaconda\lib\site-packages\theano-0.7.0-py2.7.egg\theano\misc\safe_asarray.py", line 33, in _asarray
    rval = numpy.asarray(a, dtype=dtype, order=order)
  File "C:\Anaconda\lib\site-packages\numpy\core\numeric.py", line 462, in asarray
    return array(a, dtype, copy=False, order=order)
TypeError: ('Bad input argument to theano function with name "Classifier.py:117"  at index 0(0-based)', 'float() argument must be a string or a number')

What does this error mean? Is there something wrong with the getting intermediate layer output code?

Thanks!

[MLWave]

@xypan1232

I got the same for Keras 1.0.

AttributeError: 'Sequential' object has no attribute '_predict'

Changing to predict fixed it for me.

[damaha]

Small changes have happened in Keras 1.0 and the function I posted earlier should be changed to this:

from keras import backend as K
def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], model.layers[layer].output)
    activations = get_activations([X_batch,0])
    return activations

layer being an integer index. With the new functional API to define graph structured models you should be able to use the same function (above) in any defined model as long as you know the index of the layer you want hidden activations extracted from.

[artemyk]

Got an error running the previous code. Had to modify it so that output is also a list:

from keras import backend as K
def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], [model.layers[layer].output,])
    activations = get_activations([X_batch,0])
    return activations

[EpochalEngineer]

In addition to setting up a test point at every layer I want to inspect, I have to run the batch through each test point separately?

Is there not a way to run one batch and get data from every test point?

[jdoerrie]

I just ran into a situation where I was using the Functional API similar to the one described in http://keras.io/getting-started/faq/#how-can-i-visualize-the-output-of-an-intermediate-layer. Unfortunately, I did not have access to the inputs and encoded variables anymore, so that the proposed solution

encoder = Model(input=inputs, output=encoded)
X_encoded = encoder.predict(X)

was not possible. My situation was similar to this:

def get_model():
    inputs = Input(shape=(784,), name='input')
    encoded = Dense(32, activation='relu', name='encoded')(inputs)
    decoded = Dense(784)(encoded)
    model = Model(input=inputs, output=decoded)

def get_encoded(model, X):
    # Want to get encoder output here

model = get_model()
get_encoded(model, X)

Note that I manually named the relevant layers.

I was hoping a simple

input_layer = model.get_layer('input')
encoded_layer = model.get_layer('encoded')
encoder = Model(input=input_layer, output=encoded_layer)

would work, however since those are layers and not tensors an exception is thrown (https://github.com/fchollet/keras/blob/master/keras/engine/topology.py#L1545-L1549).

After digging up the source of Layer.__call__ (https://github.com/fchollet/keras/blob/master/keras/engine/topology.py#L489-L500) my workaround was

input_layer = model.get_layer('input')
encoded_layer = model.get_layer('encoded')

input_tensor = input_layer.inbound_nodes[-1].output_tensors[0]
encoded_tensor = encoded_layer.inbound_nodes[-1].output_tensors[0]

encoder = Model(input=input_tensor, output=encoded_layer)

This of course will break if the __call__ logic changes, but it might be useful anyway. Also I was wondering whether it would make sense to make the Model constructor more forgiving and allow passing layers. Thoughts?

[jinopallickal]

@damaha @artemyk

When I run this code for a 3 Layer CNN ..it was working perfectly

but for a 4 Layer CNN it show some error like core dump error...what may be the reason

from keras import backend as K def get_activations(model, layer, X_batch): get_activations = K.function([model.layers[0].input, K.learning_phase()], model.layers[layer].output) activations = get_activations([X_batch,0]) return activations

[davharris]

It seems like this is an ongoing issue (I'm the 15th person to comment in this thread over the course of a year, and the same question was asked in #53, #89, #113, and #621). Would it make sense to add a get_activations function to the package that users can call like get_weights?

[alyato]

hi @magic282 ,Do you solve your question? There is some wrong with my code.

model = graph() model.add_input(name='input0',input_shape=()) model.add_node(Convolution2D(),name='c1',input='input0') .......

And i want to see the output of the c1,Then

getFeatureMap = theano.function(model.inputs['input0'].input,model.nodes['c1'].get_output(train=False), allow_input_downcast=True)

But it show me that TypeError: list indices must be integers, not str

[magic282]

@alyato sorry I am using other tools now.

[alyato]

@damaha ,i use the graph model.

model = graph() model.add_input(name='input0',input_shape=()) model.add_node(Convolution2D(),name='c1',input='input0') .......

And i want to see the output of the c1,Then

getFeatureMap = theano.function(model.inputs['input0'].input,model.nodes['c1'].get_output(train=False), allow_input_downcast=True)

But it show me that TypeError: list indices must be integers, not str

Do you give me some advice,please. Thanks.

[Paethon]

I also needed this. I am honestly quite surprised that there is no straight forward method of getting the response of layers for a specific input. Is there any plan on adding this to the API?

[alyato]

@Paethon ,Does your version of keras is 1.0.3 or latest? I think that its easy to do when your version is the newest.

[damaha]

Hi @alyato The error you get suggest you're indexing a list with a string. That is not possible in python. Instead of,

theano.function(model.inputs['input0'].input,model.nodes['c1'].get_output(train=False),
allow_input_downcast=True)

You should write,

theano.function(model.inputs[index_of_layer_input0].input,model.nodes[index_of_layer_c1].get_output(train=False),
allow_input_downcast=True)

in your case I believe index_of_layer_input0 = 0, index_of_layer_c1=1, but please check this yourself. You can use model.get_cofig() and look at the layer indicies. If you read my comment earlier in this thread I also explicitly states this.

layerbeing an integer index.

In the config dictionary under the layer item, layers properties (here among names) are given in a python list. It is this list index you need to find when you want to extract layer activations in the future.

[alyato]

@damaha Thanks for your reply. The version of keras is 1.0.3 I rewite my code.

theano.function(model.inputs[0].input,model.nodes[1].get_output(train=False), allow_input_downcast=True)

Then it show me that:

AttributeError: 'TensorVariable' object has no attribute 'input'

so i change it,

theano.function(model.inputs[0].get_input,model.nodes[1].get_output(train=False), allow_input_downcast=True)

it show me ,

AttributeError: 'TensorVariable' object has no attribute 'get_input'

Thanks.

[damaha]

@alyato

I was a bit quick in copying you code before and not checking if it made sense. From Keras >1.0.0 layers doesn't have a method called get_output(). In my second comment in this thread I also state this and rewrite the proposed get_activations() function that has been proposed. Instead you need to use the attribute layers[index].ouput

Another thing is wrong in your code. Keras 1.0.3 doesn't even have a model type named graph(), it has Graph() which is imported from a module named .legacy.models, I highly recommend that you DO NOT use this! Instead use the new functional API which has a nice introduction here https://keras.io/getting-started/functional-api-guide/ This is how you do DAG models in keras now. In your simple toy case above you could also use Sequential models.

Here is example code that works with the functional API and Keras 1.1.0 (Should work in any version > 1.0.0):

import numpy as np
from keras.layers import Input, Dense, Convolution2D, Flatten
from keras.models import Model
import keras.backend as K

def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], model.layers[layer].output)
    activations = get_activations([X_batch,0])
    return activations

inputs = Input(shape=(1,28,28))

x = Convolution2D(64,3,3)(inputs)
x = Flatten()(x)
predictions = Dense(10, activation='softmax')(x)

model = Model(input=inputs, output=predictions)
model.compile(optimizer='rmsprop',
              loss='categorical_crossentropy',
              metrics=['accuracy'])

X = np.ones((10,1,28,28))
my_featuremaps = get_activations(model, 1, X)

[alyato]

@damaha ,Thank you for your patience. I now learn to use the latest version and the new functional API is so cool,but it show me another issue which i post it #4280. I'm using the 1.0.3 before,using the Graph model. i just want to extract the feature_map and input the svm by Graph model.

[alyato]

@damaha i got it. Thanks again. And how can i know the index of the layers?
such as, the index of c_1 or the index of c_2

input | | c_1 c_2 | merge(c_1,c_2)

[fractalvision]

@alyato it's the index of a needed layer in model.layers, so smth like dict(enumerate(model.layers)).

[alyato]

@fractalvision ，Thanks.But i also don't understand.Do you explain what you say in detail. I call the model.get_config(), getting the following result. we can check the sequence of class_name like,

the index of input is 0 the index of ZeroPadding is 1

Is it right?

[generallc]

@fchollet @damaha Suppose the model is fully-convolutional nets and has merge layer, when the input image size is not equal to the training patch size, I can not get the merge layer activations. for example the model is:

when the input size is 64 X 64, I can get any layer activations using the function you refer. when the input size is 576 X 720, I can get the first , second and third layer activations. But I can not get the fifth layer(After the merge layer) activation. The error is as follows

Maybe this is because this model uses Deconvolution networks, whose output shape must be predetermined.This causes the model to fail to predict different images of different image sizes.https://github.com/titu1994/Image-Super-Resolution/blob/master/models.py

[srv902]

How do I modify the output of a hidden layer before passing it to the next layer, like division or multiplication ??

[philipperemy]

More generally you can visualise the output/activations of every layer of your model. I wrote an example with MNIST to show how here:

https://github.com/philipperemy/keras-visualize-activations

So far it's the less painful I've seen.

[cpury]

The code posted here by @damaha and @artemyk works great for most layers, but I'm working with RNNs and would like to get the activations of each cell for each datapoint in the input sequence.

It seems like the code only returns the final output after the whole sequence was processed.

Any ideas?

[philipperemy]

@cpury you should be able to use this trick:

Suppose your sequence is [0, 2, 3, 5, 6].

You are able to extract the activations after the whole sequence is processed, right?

So why don't you just subsample iteratively from the initial sequence? Here we go:

Input your sequence 1: [0] -> get the activations 1 (just after RNN) Input your sequence 2: [0, 2] -> get the activations 2 (just after RNN) Input your sequence 3: [0, 2, 3] -> get the activations 3 (just after RNN) Input your sequence 4: [0, 2, 3, 5] -> get the activations 4 (just after RNN) Input your sequence 5: [0, 2, 3, ,5, 6] -> get the activations 5(just after RNN)

Merge the activations of 1, 2, 3, 4, 5 into a list. You now have the activations for each time step.

It should work nicely but it will require O(n) computation if your sequence is of length n.

If you want something O(1), drop Keras and go straight Tensorflow!

Hope it helps

[leonardltk]

Hi, I am using Functional API for a basic classifier

Inp = Input( shape=(1,969), name='Input' ) 
x = Dense(units=512, activation='sigmoid', name='Hidden')(x)
x = Dense(units=20, activation='softmax', name='Output')(x)
model = Model(Inp, x)

After training, i would like to extract the "Hidden" layer BEFORE applying the sigmoid activation. How to i do that ?

I know for a fact that to extract the layer AFTER applying sigmoid activation will be as follows:

        Inp = model.input
        Outp = model.get_layer('Hidden').output
        curr_layer_model = Model(Inp, Outp)
        bottle_feature = curr_layer_model.predict(x)

But how do i extract BEFORE the sigmoid activation?

Thanks

[vinayakumarr]

from keras import backend as K

def get_activations(model, layer, X_batch): get_activations = K.function([model.layers[0].input, K.learning_phase()], model.layers[layer].output) activations = get_activations([X_batch,0]) print(activations) return activations

my_featuremaps = get_activations(cnn, 1, ([X_train[:10], 0])[0]) np.savetxt('featuremap.txt', my_featuremaps)

The above code is generating the below error with TensorFlow as backend

TypeError: outputs of a TensorFlow backend function should be a list or tuple.

Actually, this works fins with theano as backend

[YukiYaoxq]

@damaha hello, sorry, I want to know what's the 'predictions' stands for what. Can I see it as the output of what I want? thanks.

[haskarb]

I am using this code to get representation after model.add(Dense(hidden_dims)) this statement. Since, I am using sigmoid function values at every layer, why am I getting negative values? @damaha @artemyk @fchollet

from __future__ import print_function

from keras.preprocessing import sequence
from keras.models import Sequential, Model
from keras.layers import Dense, Dropout, Activation
from keras.layers import Embedding
from keras.layers import Conv1D, GlobalMaxPooling1D
from keras.datasets import imdb
from keras import backend as K
import numpy as np
# set parameters:
max_features = 500
maxlen = 40
batch_size = 32
embedding_dims = 50
filters = 250
kernel_size = 3
hidden_dims = 20
epochs = 2
print('Loading data...')
(x_train, y_train), (x_test, y_test) = imdb.load_data(num_words=max_features)
print(len(x_train), 'train sequences')
print(len(x_test), 'test sequences')

print('Pad sequences (samples x time)')
x_train = sequence.pad_sequences(x_train, maxlen=maxlen)
x_test = sequence.pad_sequences(x_test, maxlen=maxlen)
print('x_train shape:', x_train.shape)
print('x_test shape:', x_test.shape)
print('Build model...')
model = Sequential()
model.add(Embedding(max_features, embedding_dims, input_length=maxlen))
model.add(Dropout(0.2))
model.add(Conv1D(filters, kernel_size, padding='valid', activation='relu', strides=1))
model.add(GlobalMaxPooling1D())
model.add(Dense(hidden_dims))
model.add(Dropout(0.2))
model.add(Activation('sigmoid'))
model.add(Dense(1))
model.add(Activation('sigmoid'))

model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
model.fit(x_train, y_train, batch_size=batch_size, epochs=epochs,
validation_data=(x_test, y_test))
model.compile(loss='binary_crossentropy', optimizer='adam',   metrics=['accuracy'])
model.fit(x_train, y_train, batch_size=batch_size, epochs=1, validation_data=(x_test, y_test))
def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], [model.layers[layer].output,])
    activations = get_activations([X_batch,0])
    return activations
X_train=np.array(get_activations(model=model,layer=4, X_batch=x_train)[0], dtype=np.float32)
print(X_train)

[FiammettaC]

I have a network in Keras and my last layer is a fully connected layer with activation = softmax. I extracted the weights from the softmax (as suggested in the posts above) and multiplied them by 0 and 1 (I am trying to restrict the predictions).

How can I pass the modified softmax weights matrix to the model? Is there a way compile and fit a Keras model with updated weights?

I know about the function set_weights(), but my problem is that set_weights() expects input of shape (hidden_layers, vocab_size), while my new weights have size (len(X_train), vocab_size). Can anybody know how to do this?

This is my model:

def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], [model.layers[layer].output,])
    activations = get_activations([X_batch,0])
    return activations

model = Sequential()
model.add(Embedding(vocab_size, embedding_size, input_length=55, weights=[pretrained_weights]))
model.add(Bidirectional(LSTM(units=embedding_size)))
model.add(Dense(vocab_size, activation='softmax'))

softmax_weights = np.array(get_activations(model, 3, X_train)[0], dtype=np.float32)

modified_softmax_weights = np.multiply(softmax_weights, weights_array) 
#weights array is a binary array containing 0 and 1, according to the index of the element I would like to set to 0)`

[iagorichard]

Hi all,

I have a big question. I have trained my model and tryed to compile my second model. It works fine, but I can't predict my batch_X because I'm using images like input data.

My code to get the train and validation data is like follows: _`train_generator = train_datagen.flow_from_directory( train_data_dir, target_size=(img_width, img_height), batch_size=batch_size, class_mode='binary')

validation_generator = test_datagen.flow_from_directory( validation_data_dir, target_size=(img_width, img_height), batch_size=batch_size, classmode='binary')`

When I try to use my train_generator in model2.predict() it shows me the error ValueError: Please provide as model inputs either a single array or a list of arrays. You passed: x=<keras_preprocessing.image.DirectoryIterator object at 0x00000292311E7710>

Can anyone help me? Sorry for my bad english, I'm learning it!

Best Regards.

ACTUALIZATION A have solved that problem using it:

x_batch, y_batch = train_generator.next() activations = model2.predict(x_batch)

Thanks!

[olivierblais]

Hello, I am trying to get the hidden layer representation of the given data using the above solutions from keras import backend as K def get_activations(model, layer, X_batch): get_activations = K.function([model.layers[0].input, K.learning_phase()], [model.layers[layer].output,]) activations = get_activations([X_batch,0]) return activations

However, my model has 3 inputs, do you know how I should modify this function?

Thank you in advance

[imairish]

@alyato

I was a bit quick in copying you code before and not checking if it made sense. From Keras >1.0.0 layers doesn't have a method called get_output(). In my second comment in this thread I also state this and rewrite the proposed get_activations() function that has been proposed. Instead you need to use the attribute layers[index].ouput

Another thing is wrong in your code. Keras 1.0.3 doesn't even have a model type named graph(), it has Graph() which is imported from a module named .legacy.models, I highly recommend that you DO NOT use this! Instead use the new functional API which has a nice introduction here https://keras.io/getting-started/functional-api-guide/ This is how you do DAG models in keras now. In your simple toy case above you could also use Sequential models.

Here is example code that works with the functional API and Keras 1.1.0 (Should work in any version > 1.0.0):

import numpy as np
from keras.layers import Input, Dense, Convolution2D, Flatten
from keras.models import Model
import keras.backend as K

def get_activations(model, layer, X_batch):
    get_activations = K.function([model.layers[0].input, K.learning_phase()], model.layers[layer].output)
    activations = get_activations([X_batch,0])
    return activations

inputs = Input(shape=(1,28,28))

x = Convolution2D(64,3,3)(inputs)
x = Flatten()(x)
predictions = Dense(10, activation='softmax')(x)

model = Model(input=inputs, output=predictions)
model.compile(optimizer='rmsprop',
              loss='categorical_crossentropy',
              metrics=['accuracy'])

X = np.ones((10,1,28,28))
my_featuremaps = get_activations(model, 1, X)

How can we implement DAG-RNN in keras?

[devjaynemorais]

Could someone help me solve the following problem?

Environment: Keras==1.1.0 Theano==1.0.2 numpy==1.15.1 scipy==1.3.0

I created a fine tuning and frozen all layers except layer [2] because I want to get the activation values only from layer [2].

Network summary before freezing:

Layer (type) | Output Shape | Param # | Connected to

---

dense_1 (Dense) (None, 512) 2097664 dense_input_1[0][0]

---

dropout_1 (Dropout) (None, 512) 0 dense_1[0][0]
dense_1[0][0]

---

dense_2 (Dense) (None, 32) 16416 dropout_1[0][0]
dropout_1[1][0]

---

dropout_2 (Dropout) (None, 32) 0 dense_2[0][0]
dense_2[1][0]

---

dense_3 (Dense) (None, 1) 33 dropout_2[0][0]
dropout_2[1][0]

---

Total params: 2114113

Freezing layers:

for layer in model.layers[0:]: ------ layer.trainable = False model.layers[2].trainable = True

Network summary after freezing:

`Layer (type) | Output Shape | Param # | Connected to

---

dense_1 (Dense) (None, 512) 0 dense_input_1[0][0]

---

dropout_1 (Dropout) (None, 512) 0 dense_1[0][0]

---

dense_2 (Dense) (None, 32) 16416 dropout_1[1][0]

---

dropout_2 (Dropout) (None, 32) 0 dense_2[1][0]

---

dense_3 (Dense) (None, 1) 0 dropout_2[1][0]

---

Total params: 16416`

To print layer output [2]:

OutFunc = keras.backend.function([model2.input], [model2.layers[2].get_output_at(0)]) out_val = OutFunc([inputs])[0] print(out_val)

Returns the following output error:

MissingInputError Traceback (most recent call last)

in 1 #OutFunc = keras.backend.function([model2.input], [model2.layers[0].output]) ----> 2 OutFunc = keras.backend.function([model2.input], [model2.layers[2].get_output_at(0)]) 3 4 5 out_val = OutFunc([inputs])[0] ~/anaconda3/lib/python3.7/site-packages/keras/backend/theano_backend.py in function(inputs, outputs, updates, **kwargs) 725 return T.clip(x, min_value, max_value) 726 --> 727 728 def equal(x, y): 729 return T.eq(x, y) ~/anaconda3/lib/python3.7/site-packages/keras/backend/theano_backend.py in __init__(self, inputs, outputs, updates, **kwargs) 711 712 def pow(x, a): --> 713 return T.pow(x, a) 714 715 ~/anaconda3/lib/python3.7/site-packages/theano/compile/function.py in function(inputs, outputs, mode, updates, givens, no_default_updates, accept_inplace, name, rebuild_strict, allow_input_downcast, profile, on_unused_input) 315 on_unused_input=on_unused_input, 316 profile=profile, --> 317 output_keys=output_keys) 318 return fn ~/anaconda3/lib/python3.7/site-packages/theano/compile/pfunc.py in pfunc(params, outputs, mode, updates, givens, no_default_updates, accept_inplace, name, rebuild_strict, allow_input_downcast, profile, on_unused_input, output_keys) 484 accept_inplace=accept_inplace, name=name, 485 profile=profile, on_unused_input=on_unused_input, --> 486 output_keys=output_keys) 487 488 ~/anaconda3/lib/python3.7/site-packages/theano/compile/function_module.py in orig_function(inputs, outputs, mode, accept_inplace, name, profile, on_unused_input, output_keys) 1837 on_unused_input=on_unused_input, 1838 output_keys=output_keys, -> 1839 name=name) 1840 with theano.change_flags(compute_test_value="off"): 1841 fn = m.create(defaults) ~/anaconda3/lib/python3.7/site-packages/theano/compile/function_module.py in __init__(self, inputs, outputs, mode, accept_inplace, function_builder, profile, on_unused_input, fgraph, output_keys, name) 1485 # OUTPUT VARIABLES) 1486 fgraph, additional_outputs = std_fgraph(inputs, outputs, -> 1487 accept_inplace) 1488 fgraph.profile = profile 1489 else: ~/anaconda3/lib/python3.7/site-packages/theano/compile/function_module.py in std_fgraph(input_specs, output_specs, accept_inplace) 179 180 fgraph = gof.fg.FunctionGraph(orig_inputs, orig_outputs, --> 181 update_mapping=update_mapping) 182 183 for node in fgraph.apply_nodes: ~/anaconda3/lib/python3.7/site-packages/theano/gof/fg.py in __init__(self, inputs, outputs, features, clone, update_mapping) 173 174 for output in outputs: --> 175 self.__import_r__(output, reason="init") 176 for i, output in enumerate(outputs): 177 output.clients.append(('output', i)) ~/anaconda3/lib/python3.7/site-packages/theano/gof/fg.py in __import_r__(self, variable, reason) 344 # Imports the owners of the variables 345 if variable.owner and variable.owner not in self.apply_nodes: --> 346 self.__import__(variable.owner, reason=reason) 347 elif (variable.owner is None and 348 not isinstance(variable, graph.Constant) and ~/anaconda3/lib/python3.7/site-packages/theano/gof/fg.py in __import__(self, apply_node, check, reason) 389 "for more information on this error." 390 % (node.inputs.index(r), str(node))) --> 391 raise MissingInputError(error_msg, variable=r) 392 393 for node in new_nodes: MissingInputError: Input 0 of the graph (indices start from 0), used to compute InplaceDimShuffle{x,x}(keras_learning_phase), was not provided and not given a value. Use the Theano flag exception_verbosity='high', for more information on this error. Backtrace when that variable is created: File "", line 219, in _call_with_frames_removed File "/home/jayne/anaconda3/lib/python3.7/site-packages/keras/backend/__init__.py", line 61, in from .theano_backend import * File "", line 983, in _find_and_load File "", line 967, in _find_and_load_unlocked File "", line 677, in _load_unlocked File "", line 728, in exec_module File "", line 219, in _call_with_frames_removed File "/home/jayne/anaconda3/lib/python3.7/site-packages/keras/backend/theano_backend.py", line 23, in _LEARNING_PHASE = T.scalar(dtype='uint8', name='keras_learning_phase') # 0 = test, 1 = train