encoder updated twice for curl loss

[xy9485]

I'm looking into the code and find that in def update_cpc() both self.encoder_optimizer.step() and self.cpc_optimizer.step() are called. However the parameters of critic.encoder are carried by both optimizer. Isn't it true that, in def update_cpc(), critic.encoder is updated twice using the same gradient?

[Penelope-zhang]

@xy9485 do you know why critic.encoder is updated twice in def update_cpc()?

[LYK-love]

Yeah that's true. I don't know the reason of doing this.