Fig. 2
From: Protein remote homology detection based on bidirectional long short-term memory
The structure of LSTM memory cell. There are three gates, including input gate (marked as i), forget gate (marked as f), output gate (marked as o), to control the information stream flowing in and out the block. σ denotes the sigmoid function, which produces a value bounded by 0 and 1. The internal cell state is maintained and updated by the coordination of input gate and forget gate. The output gate controls outputting information stored in the cell. h is the output of the memory cell, x is representing matrix of the input subsequence and t mean the t th time step