问如何构建堆叠的序列到序列的自动编码器？

EN

from keras.layers import Input, LSTM, RepeatVector
from keras.models import Model

inputs = Input(shape=(timesteps, input_dim))
encoded = LSTM(latent_dim)(inputs)

decoded = RepeatVector(timesteps)(encoded)
decoded = LSTM(input_dim, return_sequences=True)(decoded)

sequence_autoencoder = Model(inputs, decoded)
encoder = Model(inputs, encoded)

timesteps = 3
input_dim = 1
inputs = Input(shape=(timesteps, input_dim))
encoded = LSTM(4)(inputs)
encoded = RepeatVector(timesteps)(encoded)
encoded = LSTM(2)(encoded)
encoded = RepeatVector(timesteps)(encoded)
decoded = LSTM(4,return_sequences = True)(encoded)
decoded = LSTM(input_dim,return_sequences = True)(decoded)

sequence_autoencoder = Model(inputs, decoded)

sequence_autoencoder.compile(loss='mean_squared_error', optimizer='Adam')

sequence_autoencoder.fit(x_train, x_train,
epochs=100,
batch_size=1,
shuffle=True,
)