Pointer mechanism: Due to the limitation of the vocabulary size, some keywords may not be in the target vocabulary, which will certainly lead to a lack of them in the final summary.
we take the key information representation k, the context vector c t and the decoder hidden state s t as inputs to calculate a soft switch p sw , which is used to choose between generating a word from the target vocabulary or copying a word from the input text: where w T k , w T c , w T s and b sw are parameters, σ is the sigmoid function.