The goal of retrieval-based dialogue systems is then to learn a predictive distribution p(y|c, r, θ) parameterized by θ.
given a context c and re-sponse r, we would like to infer the probability of r being a response to context c. Recurrent neural networks are one of the most popular classes of models for processing sequences of words W = {w t } T t=1 with arbitrary length T ∈ N, e.g.