@startuml serial_collector
header Serial Pipeline
title Serial Collector

|#99CCCC|serial_controller|
|#99CCFF|env_manager|
|#CCCCFF|policy|
|#FFCCCC|collector|

|#99CCCC|serial_controller|
start
:init collector, set its \nenv_manager and \ncollect_mode policy;
|#99CCFF|env_manager|
repeat
  |#99CCFF|env_manager|
  :return current obs;
  |#CCCCFF|policy|
  :<b>[network]</b> forward with obs;
  |#99CCFF|env_manager|
  :env step with action;
  |#CCCCFF|policy|
  :process transition;
  |#FFCCCC|collector|
  :save transition in cache;
  if (for every env: \n env_i is done? <b>OR</b> cache is full?) then (yes)
    if (is <b>sample_collector</b>?) then (yes)
    note right: Only sample_collector will do so, \n episode_collector will not.
      |#CCCCFF|policy|
      :<b>[adder]</b> get train_sample from cache;
    endif
    |#FFCCCC|collector|
    :save sample/episode for return;
    if (env_i is done?) then (yes)
      |#99CCFF|env_manager|
      :env_i reset;
    endif
  endif
|#FFCCCC|collector|
repeat while (collected sample/episode is not enough?)
:return sample/episode;
stop

@enduml