marl-factory-grid/algorithms/vdn_learner.py
2021-06-23 10:56:18 +02:00

23 lines
1.2 KiB
Python

import torch
from algorithms.q_learner import QLearner
class VDNLearner(QLearner):
def __init__(self, *args, **kwargs):
super(VDNLearner, self).__init__(*args, **kwargs)
assert self.n_agents >= 2, 'VDN requires more than one agent, use QLearner instead'
def train(self):
if len(self.buffer) < self.batch_size: return
for _ in range(self.n_grad_steps):
experience = self.buffer.sample(self.batch_size, cer=self.train_every_n_steps)
pred_q, target_q_raw = torch.zeros((self.batch_size, 1)), torch.zeros((self.batch_size, 1))
for agent_i in range(self.n_agents):
q_values, next_q_values_raw = self._training_routine(experience.observation[:, agent_i],
experience.next_observation[:, agent_i],
experience.action[:, agent_i].unsqueeze(-1))
pred_q += q_values
target_q_raw += next_q_values_raw
target_q = experience.reward + (1 - experience.done) * self.gamma * target_q_raw
loss = torch.mean(self.reg_weight * pred_q + torch.pow(pred_q - target_q, 2))
self._backprop_loss(loss)