Adding a convolutional layer

We can add one-dimensional CNN and max-pooling layers after the embedding layer, which will then feed the consolidated features to the LSTM.

Here is our embedding layer:

model = Sequential() 
model.add(Embedding(top_words,\ 
           embedding_vector_length,\ 
               input_length=max_review_length))

We can apply a convolution layer with a small kernel filter (filter_length) of size 3, with 32 output features (nb_filter):

model.add(Conv1D (padding="same", activation="relu", kernel_size=3,\ num_filter=32))

Next, we add a pooling layer; the size of the region to which max pooling is applied is equal to 2:

model.add(GlobalMaxPooling1D ())

The next layer is a LSTM layer, with 100 memory units:

model.add(LSTM(100))

The final layer is a Dense output layer, with a single neuron and a sigmoid activation function, to make 0 or 1 predictions for the two classes (good...