follow the OpenAI GPT-2 to model a multiturn dialogue session as a long text and frame the generation task as language
modeling. We first concatenate all dialog turns within a dialogue session into a long text x_1,..., x_N (N is the
sequence length), ended by the end-of-text token. For more information please confer to the original paper.
DialoGPT's architecture is based on the GPT2 model, so one can refer to GPT2's documentation page.
The original code can be found here.
