This is the code for implementing the PRD-MAPPO algorithm presented in the paper: Assigning Credit with Partial Reward Decoupling in Multi-Agent Proximal Policy Optimization. It is configured to be run in conjunction with the following environments:

• Multi-Agent Particle Environments (MPE).
• Pressure Plate (PP)
• MultiAgent Gym (MA-GYM)

Alert: Please note that the environments listed above are customised and hence one should use the environment directories provided in the above codebase instead

• To install MPE, PP, or MA-GYM, cd into the root directory and type pip install -e .

• Known dependencies for MPE: Python (3.6+), OpenAI gym (0.10.5), torch (1.10.0+cu102), numpy (1.21.5)

• Known dependencies for PP: Python (3.6+), OpenAI gym (0.23.1), torch (1.11.0+cu102), numpy (1.22.3)

• Known dependencies for MA-GYM: Python (3.6+), OpenAI gym (0.19.0), torch (1.11.0+cu102), numpy (1.22.3)

You can find these parameters in the main.py file for all the environments.

• iteration: seed index (default: 0, options: 0, 1, 2, 3, 4)

• update_type: policy update algorithm (default: ppo, options: ppo, a2c)

• attention_type: transformer attention mechanism for the critic network (default: soft, options: soft, semi-hard)

• device: device to run the code on (default: gpu, option: gpu, cpu)

• grad_clip_critic: gradient clip for critic network (default: 10.0 (MPE) or 0.5 (MA-GYM/PP))

• grad_clip_actor: gradient clip for actor network (default: 10.0 (MPE) or 0.5 (MA-GYM/PP))

• critic_dir: directory to save critic network models

• actor_dir: directory to save actor network models

• gif_dir: directory to save gifs

• policy_eval_dir: directory to save policy metrics

• policy_clip: imposes a clip interval on the probability ratio term while computing policy loss, which is clipped into a range [1 — policy_clip, 1 + policy_clip] (default: 0.05)

• value_clip: imposes a clip interval on the probability ratio term while computing value loss, which is clipped into a range [1 — value_clip, 1 + value_clip] (default: 0.05)

• n_epochs: number of epochs to train the policy and critic network (default: 5)

• env: environment name

• value_lr: critic learning rate (default: 1e-3 (Crossing) or 3e-4 (Combat) or 7e-4 (Pressure Plate) or 5e-5 (Traffic Junction))

• policy_lr: actor learning rate (default: 7e-4 (Crossing) or 3e-4 (Combat) or 7e-4 (Pressure Plate) or 5e-5 (Traffic Junction))

• entropy_pen: entropy penalty (default: 0.0 (Crossing) or 8e-3 (Combat) or 0.4 (Pressure Plate) or 0.0 (Traffic Junction))

• gamma: discount factor (default: 0.99)

• gae_lambda: temperature factor for Generalized Advantage Estimation (default: 0.95)

• lambda: temperature factor for computing TD-lambda targets (default: 0.95)

• select_above_threshold: weight threshold to identify relevant set (default: 0.05 (Crossing) or 0.2 (Combat) or 0.05 (Pressure Plate) or 0.2 (Traffic Junction))

• gif: enable rendering of gif

• gif_checkpoint: episodes after which render gif (default: 1)

• load_models: enable to load critic and actor models

• model_path_value: critic model path

• model_path_policy: actor model path

• eval_policy: enable to capture policy evaluation metrics

• save_model: enable to save critic and actor models

• save_model_checkpoint: save model after save_model_checkpoint episodes

• save_comet_ml_plot: enable to record data on comet

• learn: enable updating critic and actor networks

• max_episodes: total number of episodes (default: 80K (Crossing) or 120K (Combat) or 20K (Pressure Plate) or 20K (Traffic Junction))

• max_time_steps: number of timesteps per episode (default: 50 (Crossing) or 40 (Combat) or 70 (Pressure Plate) or 40 (Traffic Junction))

• experiment_type: type of update (default: prd, options: prd, shared (fully cooperative))

• ./Agent MA GYM/MA_Controller/Combat/main.py: contains code for setting parameters of PRD-MAPPO on the MA-GYM Combat environment

• ./Agent MA GYM/MA_Controller/Traffic_Junc/main.py: contains code for setting parameters of PRD-MAPPO on the MA-GYM Traffic Junction environment

• ./Agent MPE/MA_Controller/main.py: contains code for setting parameters of PRD-MAPPO on the MPE Crossing environment

• ./Agent Pressure Plate/MA_Controller/main.py: contains code for setting parameters of PRD-MAPPO on the PP 4 Person Pressure Plate environment

• ./Agent MA GYM/MA_Controller/Combat/agent.py or ./Agent MA GYM/MA_Controller/Traffic_Junc/agent.py or ./Agent Pressure Plate/MA_Controller/agent.py or ./Agent MPE/MA_Controller/agent.py: core code for the PRD-MAPPO algorithm

• ./Agent MA GYM/MA_Controller/Combat/multiagent.py or ./Agent MA GYM/MA_Controller/Traffic_Junc/multiagent.py or ./Agent Pressure Plate/MA_Controller/multiagent.py or ./Agent MPE/MA_Controller/multiagent.py: code that deals with environment and agent interaction

• ./Agent MA GYM/MA_Controller/Combat/model.py or ./Agent MA GYM/MA_Controller/Traffic_Junc/model.py or ./Agent Pressure Plate/MA_Controller/model.py or ./Agent MPE/MA_Controller/model.py: Policy, Q Network, Replay Buffer code for PRD-MAPPO