This resembles the siamese network https://keras.io/getting-started/functional-api-guide/#shared-layers
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import keras
from keras.layers import Input, LSTM, Dense
from keras.models import Model
    
    
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tweet_a = Input(shape=(140, 256))
tweet_b = Input(shape=(140, 256))
    
To share a layer across different inputs, simply instantiate the layer once, then call it on as many inputs as you want:
In [3]:
    
# This layer can take as input a matrix
# and will return a vector of size 64
shared_lstm = LSTM(64)
    
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# When we reuse the same layer instance
# multiple times, the weights of the layer
# are also being reused
# (it is effectively *the same* layer)
encoded_a = shared_lstm(tweet_a)
encoded_b = shared_lstm(tweet_b)
    
In [5]:
    
# We can then concatenate the two vectors:
merged_vector = keras.layers.concatenate([encoded_a, encoded_b], axis=-1)
# And add a logistic regression on top
predictions = Dense(1, activation='sigmoid')(merged_vector)
# We define a trainable model linking the
# tweet inputs to the predictions
model = Model(inputs=[tweet_a, tweet_b], outputs=predictions)
model.compile(optimizer='rmsprop',
              loss='binary_crossentropy',
              metrics=['accuracy'])
model.fit([data_a, data_b], labels, epochs=10)
    
    
Example architecture needs to find data to run example
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