What is num_units in tensorflow BasicLSTMCell?

Question

In MNIST LSTM examples, I don\'t understand what \"hidden layer\" means. Is it the imaginary-layer formed when you represent an unrolled RNN over time?

Why is the <

Answer 1

An LSTM keeps two pieces of information as it propagates through time:

A hidden state; which is the memory the LSTM accumulates using its (forget, input, and output) gates through time, and The previous time-step output.

Tensorflow’s num_units is the size of the LSTM’s hidden state (which is also the size of the output if no projection is used).

To make the name num_units more intuitive, you can think of it as the number of hidden units in the LSTM cell, or the number of memory units in the cell.

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