ReplayBuffer.update does not change stats while adding data

[Jimenius]

• [X] I have marked all applicable categories:
  • [ ] exception-raising bug
  • [X] RL algorithm bug
  • [ ] documentation request (i.e. "X is missing from the documentation.")
  • [ ] new feature request
• [X] I have visited the source website
• [X] I have searched through the issue tracker for duplicates
• [ ] I have mentioned version numbers, operating system and environment, where applicable:

  import tianshou, torch, numpy, sys
  print(tianshou.__version__, torch.__version__, numpy.__version__, sys.version, sys.platform)
  

Are any algorithms using ReplayBuffer.update method, or it's just a legacy? It doesn't seem to keep track of the statististics (ep_rew, ep_len etc.) while adding data.

[Trinkle23897]

Just a legacy. It's because before version 0.4, tianshou uses the following pipeline to collect data:

[main_buffer] + [list of cached buffer for storing episode]

once an episode (say, ith env) finishes, it moves data from cache_buffer[i] to main_buffer via .update()