TensorFlow uses a data structure called LSTMStateTuple internally for its LSTM:s, where the first element in the tuple is the cell state, and the second is the hidden state. So you need to change line 28 where the init_state is placeholders are declared to these lines:Using the LSTM API in TensorFlow (3/7)49815Erik HallströmSagar GandhiFollowSep 8, 2018 · 1 min readThis is wrong. The first element is a hidden state and second element is a cell output.