Keras LSTM with varying timesteps

Question

Suppose the input to the model is a series of vectors, each with equal length. However, the number of vectors in each input can change. I want to make an LSTM model using Keras, but if I were to write

input = keras.layers.input(dims)
img_out = keras.layers.recurrent.LSTM(16)

Then what would I put for "dims"? Thanks so much.

Answer 1

You can fix an upper bound for dims. When the input is less than dims, you can pad the rest with zero vector.