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storage.py
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storage.py
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import torch
from torch.utils.data.sampler import BatchSampler, SubsetRandomSampler
def _flatten_helper(T, N, _tensor):
return _tensor.view(T * N, *_tensor.size()[2:])
class RolloutStorage(object):
def __init__(self, num_steps, num_processes, obs_shape, action_space, recurrent_hidden_state_size):
self.obs = torch.zeros(num_steps + 1, num_processes, *obs_shape)
self.recurrent_hidden_states = torch.zeros(num_steps + 1, num_processes, recurrent_hidden_state_size)
self.rewards = torch.zeros(num_steps, num_processes, 1)
self.value_preds = torch.zeros(num_steps + 1, num_processes, 1)
self.returns = torch.zeros(num_steps + 1, num_processes, 1)
self.action_log_probs = torch.zeros(num_steps, num_processes, 1)
if action_space.__class__.__name__ == 'Discrete':
action_shape = 1
else:
action_shape = action_space.shape[0]
self.actions = torch.zeros(num_steps, num_processes, action_shape)
if action_space.__class__.__name__ == 'Discrete':
self.actions = self.actions.long()
self.masks = torch.ones(num_steps + 1, num_processes, 1)
self.num_steps = num_steps
self.step = 0
def to(self, device):
self.obs = self.obs.to(device)
self.recurrent_hidden_states = self.recurrent_hidden_states.to(device)
self.rewards = self.rewards.to(device)
self.value_preds = self.value_preds.to(device)
self.returns = self.returns.to(device)
self.action_log_probs = self.action_log_probs.to(device)
self.actions = self.actions.to(device)
self.masks = self.masks.to(device)
def insert(self, obs, recurrent_hidden_states, actions, action_log_probs, value_preds, rewards, masks):
self.obs[self.step + 1].copy_(obs)
self.recurrent_hidden_states[self.step + 1].copy_(recurrent_hidden_states)
self.actions[self.step].copy_(actions)
self.action_log_probs[self.step].copy_(action_log_probs)
self.value_preds[self.step].copy_(value_preds)
self.rewards[self.step].copy_(rewards)
self.masks[self.step + 1].copy_(masks)
self.step = (self.step + 1) % self.num_steps
def after_update(self):
self.obs[0].copy_(self.obs[-1])
self.recurrent_hidden_states[0].copy_(self.recurrent_hidden_states[-1])
self.masks[0].copy_(self.masks[-1])
def compute_returns(self, next_value, use_gae, gamma, tau):
if use_gae:
self.value_preds[-1] = next_value
gae = 0
for step in reversed(range(self.rewards.size(0))):
delta = self.rewards[step] + gamma * self.value_preds[step + 1] * self.masks[step + 1] - self.value_preds[step]
gae = delta + gamma * tau * self.masks[step + 1] * gae
self.returns[step] = gae + self.value_preds[step]
else:
self.returns[-1] = next_value
for step in reversed(range(self.rewards.size(0))):
self.returns[step] = self.returns[step + 1] * \
gamma * self.masks[step + 1] + self.rewards[step]
def feed_forward_generator(self, advantages, num_mini_batch):
num_steps, num_processes = self.rewards.size()[0:2]
batch_size = num_processes * num_steps
assert batch_size >= num_mini_batch, (
"PPO requires the number of processes ({}) "
"* number of steps ({}) = {} "
"to be greater than or equal to the number of PPO mini batches ({})."
"".format(num_processes, num_steps, num_processes * num_steps, num_mini_batch))
mini_batch_size = batch_size // num_mini_batch
sampler = BatchSampler(SubsetRandomSampler(range(batch_size)), mini_batch_size, drop_last=False)
for indices in sampler:
obs_batch = self.obs[:-1].view(-1, *self.obs.size()[2:])[indices]
recurrent_hidden_states_batch = self.recurrent_hidden_states[:-1].view(-1,
self.recurrent_hidden_states.size(-1))[indices]
actions_batch = self.actions.view(-1, self.actions.size(-1))[indices]
value_preds_batch = self.value_preds[:-1].view(-1, 1)[indices]
return_batch = self.returns[:-1].view(-1, 1)[indices]
masks_batch = self.masks[:-1].view(-1, 1)[indices]
old_action_log_probs_batch = self.action_log_probs.view(-1, 1)[indices]
adv_targ = advantages.view(-1, 1)[indices]
yield obs_batch, recurrent_hidden_states_batch, actions_batch, \
value_preds_batch, return_batch, masks_batch, old_action_log_probs_batch, adv_targ
def recurrent_generator(self, advantages, num_mini_batch):
num_processes = self.rewards.size(1)
assert num_processes >= num_mini_batch, (
"PPO requires the number of processes ({}) "
"to be greater than or equal to the number of "
"PPO mini batches ({}).".format(num_processes, num_mini_batch))
num_envs_per_batch = num_processes // num_mini_batch
perm = torch.randperm(num_processes)
for start_ind in range(0, num_processes, num_envs_per_batch):
obs_batch = []
recurrent_hidden_states_batch = []
actions_batch = []
value_preds_batch = []
return_batch = []
masks_batch = []
old_action_log_probs_batch = []
adv_targ = []
for offset in range(num_envs_per_batch):
ind = perm[start_ind + offset]
obs_batch.append(self.obs[:-1, ind])
recurrent_hidden_states_batch.append(self.recurrent_hidden_states[0:1, ind])
actions_batch.append(self.actions[:, ind])
value_preds_batch.append(self.value_preds[:-1, ind])
return_batch.append(self.returns[:-1, ind])
masks_batch.append(self.masks[:-1, ind])
old_action_log_probs_batch.append(self.action_log_probs[:, ind])
adv_targ.append(advantages[:, ind])
T, N = self.num_steps, num_envs_per_batch
# These are all tensors of size (T, N, -1)
obs_batch = torch.stack(obs_batch, 1)
actions_batch = torch.stack(actions_batch, 1)
value_preds_batch = torch.stack(value_preds_batch, 1)
return_batch = torch.stack(return_batch, 1)
masks_batch = torch.stack(masks_batch, 1)
old_action_log_probs_batch = torch.stack(old_action_log_probs_batch, 1)
adv_targ = torch.stack(adv_targ, 1)
# States is just a (N, -1) tensor
recurrent_hidden_states_batch = torch.stack(recurrent_hidden_states_batch, 1).view(N, -1)
# Flatten the (T, N, ...) tensors to (T * N, ...)
obs_batch = _flatten_helper(T, N, obs_batch)
actions_batch = _flatten_helper(T, N, actions_batch)
value_preds_batch = _flatten_helper(T, N, value_preds_batch)
return_batch = _flatten_helper(T, N, return_batch)
masks_batch = _flatten_helper(T, N, masks_batch)
old_action_log_probs_batch = _flatten_helper(T, N, \
old_action_log_probs_batch)
adv_targ = _flatten_helper(T, N, adv_targ)
yield obs_batch, recurrent_hidden_states_batch, actions_batch, \
value_preds_batch, return_batch, masks_batch, old_action_log_probs_batch, adv_targ