Shortcuts

Source code for ding.rl_utils.coma

from collections import namedtuple
import torch
import torch.nn.functional as F
from ding.rl_utils.td import generalized_lambda_returns

coma_data = namedtuple('coma_data', ['logit', 'action', 'q_value', 'target_q_value', 'reward', 'weight'])
coma_loss = namedtuple('coma_loss', ['policy_loss', 'q_value_loss', 'entropy_loss'])


[docs]def coma_error(data: namedtuple, gamma: float, lambda_: float) -> namedtuple: """ Overview: Implementation of COMA Arguments: - data (:obj:`namedtuple`): coma input data with fieids shown in ``coma_data`` Returns: - coma_loss (:obj:`namedtuple`): the coma loss item, all of them are the differentiable 0-dim tensor Shapes: - logit (:obj:`torch.FloatTensor`): :math:`(T, B, A, N)`, where B is batch size A is the agent num, and N is \ action dim - action (:obj:`torch.LongTensor`): :math:`(T, B, A)` - q_value (:obj:`torch.FloatTensor`): :math:`(T, B, A, N)` - target_q_value (:obj:`torch.FloatTensor`): :math:`(T, B, A, N)` - reward (:obj:`torch.FloatTensor`): :math:`(T, B)` - weight (:obj:`torch.FloatTensor` or :obj:`None`): :math:`(T ,B, A)` - policy_loss (:obj:`torch.FloatTensor`): :math:`()`, 0-dim tensor - value_loss (:obj:`torch.FloatTensor`): :math:`()` - entropy_loss (:obj:`torch.FloatTensor`): :math:`()` Examples: >>> action_dim = 4 >>> agent_num = 3 >>> data = coma_data( >>> logit=torch.randn(2, 3, agent_num, action_dim), >>> action=torch.randint(0, action_dim, (2, 3, agent_num)), >>> q_value=torch.randn(2, 3, agent_num, action_dim), >>> target_q_value=torch.randn(2, 3, agent_num, action_dim), >>> reward=torch.randn(2, 3), >>> weight=torch.ones(2, 3, agent_num), >>> ) >>> loss = coma_error(data, 0.99, 0.99) """ logit, action, q_value, target_q_value, reward, weight = data if weight is None: weight = torch.ones_like(action) q_taken = torch.gather(q_value, -1, index=action.unsqueeze(-1)).squeeze(-1) target_q_taken = torch.gather(target_q_value, -1, index=action.unsqueeze(-1)).squeeze(-1) T, B, A = target_q_taken.shape reward = reward.unsqueeze(-1).expand_as(target_q_taken).reshape(T, -1) target_q_taken = target_q_taken.reshape(T, -1) return_ = generalized_lambda_returns(target_q_taken, reward[:-1], gamma, lambda_) return_ = return_.reshape(T - 1, B, A) q_value_loss = (F.mse_loss(return_, q_taken[:-1], reduction='none') * weight[:-1]).mean() dist = torch.distributions.categorical.Categorical(logits=logit) logp = dist.log_prob(action) baseline = (torch.softmax(logit, dim=-1) * q_value).sum(-1).detach() adv = (q_taken - baseline).detach() entropy_loss = (dist.entropy() * weight).mean() policy_loss = -(logp * adv * weight).mean() return coma_loss(policy_loss, q_value_loss, entropy_loss)