Add DDPGfD, TD3fD and SACfD (#22)

* Format repository

* Clone files from medipixel repo

* Fix DDPGfDAgent.update_model()

* Fix bug on _initialize()

* Add demo-path parameter and demo data

* Rename init_priority to _max_priority for PER

This makes PER and PERfD consistent.

* Make i_episode attribute of DDPGAgent

* Clone SAC code from medipixel repo

* Fix update_model() for SACfD

* Fix _initialize() for SACfD

* Add is_discrete attribute to AbstractAgent for SACfD

* Add i_episode attribute to SACAgent for SACfD

* Modularize DDPGAgent and SACAgent

* Modify hyperparameters for DDPGfD and SACfD

* Add NStepBuffer

* Add n-step to DDPGfD

* Add n-step to SACfD

* Add TD3fD without n-step

* Attempt to tune hyperparameters

* Remove discrete environment check in SAC

* Implement n-step on TD3fD

* Fix step function of TD3

No done check, and _add_transition_to_memory was not called.

* Fix actor loss calculation for TD3fD

* Attempt to tune hyperparameters

* Print both critic losses

* Fix typo bug

* Attempt to tune hyperparameters

* Fix bug in n-step demo retrieval

* Fix bug in n-step transition addition

scripts/algorithms/common/abstract/agent.py

@@ -37,6 +37,7 @@ class AbstractAgent(ABC):
         """
         self.args = args
         self.env = NormalizedActions(env)
+
         if self.args.max_episode_steps > 0:
             env._max_episode_steps = self.args.max_episode_steps
         else: