bug fix for clipped ppo for discrete controls

rl_coach/agents/clipped_ppo_agent.py

@@ -194,7 +194,9 @@ class ClippedPPOAgent(ActorCriticAgent):
                 for input_index, input in enumerate(old_policy_distribution):
                     inputs['output_1_{}'.format(input_index + 1)] = input
 
-                inputs['output_1_3'] = self.ap.algorithm.clipping_decay_schedule.current_value
+                # update the clipping decay schedule value
+                inputs['output_1_{}'.format(len(old_policy_distribution)+1)] = \
+                    self.ap.algorithm.clipping_decay_schedule.current_value
 
                 total_loss, losses, unclipped_grads, fetch_result = \
                     self.networks['main'].train_and_sync_networks(

rl_coach/exploration_policies/exploration_policy.py

@@ -52,7 +52,12 @@ class ExplorationPolicy(object):
         :param action_values: A list of action values
         :return: The chosen action
         """
-        pass
+        if self.__class__ == ExplorationPolicy:
+            raise ValueError("The ExplorationPolicy class is an abstract class and should not be used directly. "
+                             "Please set the exploration parameters to point to an inheriting class like EGreedy or "
+                             "AdditiveNoise")
+        else:
+            raise ValueError("The get_action function should be overridden in the inheriting exploration class")
 
     def change_phase(self, phase):
         """