Source code for ding.policy.pdqn
from typing import List, Dict, Any, Tuple
from collections import namedtuple
import copy
import torch
from ding.torch_utils import Adam, to_device
from ding.rl_utils import q_nstep_td_data, q_nstep_td_error, get_nstep_return_data, get_train_sample
from ding.model import model_wrap
from ding.utils import POLICY_REGISTRY
from ding.utils.data import default_collate, default_decollate
from .base_policy import Policy
from .common_utils import default_preprocess_learn
[docs]@POLICY_REGISTRY.register('pdqn')
class PDQNPolicy(Policy):
"""
Overview:
Policy class of PDQN algorithm, which extends the DQN algorithm on discrete-continuous hybrid action spaces.
Paper link: https://arxiv.org/abs/1810.06394.
Config:
== ==================== ======== ============== ======================================== =======================
ID Symbol Type Default Value Description Other(Shape)
== ==================== ======== ============== ======================================== =======================
1 ``type`` str pdqn | RL policy register name, refer to | This arg is optional,
| registry ``POLICY_REGISTRY`` | a placeholder
2 ``cuda`` bool False | Whether to use cuda for network | This arg can be diff-
| erent from modes
3 ``on_policy`` bool False | Whether the RL algorithm is on-policy | This value is always
| or off-policy | False for PDQN
4 ``priority`` bool False | Whether use priority(PER) | Priority sample,
| update priority
5 | ``priority_IS`` bool False | Whether use Importance Sampling Weight
| ``_weight`` | to correct biased update. If True,
| priority must be True.
6 | ``discount_`` float 0.97, | Reward's future discount factor, aka. | May be 1 when sparse
| ``factor`` [0.95, 0.999] | gamma | reward env
7 ``nstep`` int 1, | N-step reward discount sum for target
[3, 5] | q_value estimation
8 | ``learn.update`` int 3 | How many updates(iterations) to train | This args can be vary
| ``per_collect`` | after collector's one collection. Only | from envs. Bigger val
| valid in serial training | means more off-policy
9 | ``learn.batch_`` int 64 | The number of samples of an iteration
| ``size``
| ``_gpu``
11 | ``learn.learning`` float 0.001 | Gradient step length of an iteration.
| ``_rate``
12 | ``learn.target_`` int 100 | Frequence of target network update. | Hard(assign) update
| ``update_freq``
13 | ``learn.ignore_`` bool False | Whether ignore done for target value | Enable it for some
| ``done`` | calculation. | fake termination env
14 ``collect.n_sample`` int [8, 128] | The number of training samples of a | It varies from
| call of collector. | different envs
15 | ``collect.unroll`` int 1 | unroll length of an iteration | In RNN, unroll_len>1
| ``_len``
16 | ``collect.noise`` float 0.1 | add noise to continuous args
| ``_sigma`` | during collection
17 | ``other.eps.type`` str exp | exploration rate decay type | Support ['exp',
| 'linear'].
18 | ``other.eps.`` float 0.95 | start value of exploration rate | [0,1]
| ``start``
19 | ``other.eps.`` float 0.05 | end value of exploration rate | [0,1]
| ``end``
20 | ``other.eps.`` int 10000 | decay length of exploration | greater than 0. set
| ``decay`` | decay=10000 means
| the exploration rate
| decay from start
| value to end value
| during decay length.
== ==================== ======== ============== ======================================== =======================
"""
config = dict(
# (str) RL policy register name (refer to function "POLICY_REGISTRY").
type='pdqn',
# (bool) Whether to use cuda in policy.
cuda=False,
# (bool) Whether learning policy is the same as collecting data policy(on-policy).
on_policy=False,
# (bool) Whether to enable priority experience sample.
priority=False,
# (bool) Whether to use Importance Sampling Weight to correct biased update. If True, priority must be True.
priority_IS_weight=False,
# (float) Discount factor(gamma) for returns.
discount_factor=0.97,
# (int) The number of step for calculating target q_value.
nstep=1,
# learn_mode config
learn=dict(
# (int) How many updates(iterations) to train after collector's one collection.
# Bigger "update_per_collect" means bigger off-policy.
# collect data -> update policy-> collect data -> ...
update_per_collect=3,
# (int) How many samples in a training batch.
batch_size=64,
# (float) The step size of gradient descent.
learning_rate=0.001,
# (int) Frequence of target network update.
target_theta=0.005,
# (bool) Whether ignore done(usually for max step termination env).
# Note: Gym wraps the MuJoCo envs by default with TimeLimit environment wrappers.
# These limit HalfCheetah, and several other MuJoCo envs, to max length of 1000.
# However, interaction with HalfCheetah always gets done with done is False,
# Since we inplace done==True with done==False to keep
# TD-error accurate computation(``gamma * (1 - done) * next_v + reward``),
# when the episode step is greater than max episode step.
ignore_done=False,
),
# collect_mode config
collect=dict(
# (int) How many training samples collected in one collection procedure.
# Only one of [n_sample, n_episode] shoule be set.
# n_sample=8,
# (int) Split episodes or trajectories into pieces with length `unroll_len`.
unroll_len=1,
# (float) It is a must to add noise during collection. So here omits noise and only set ``noise_sigma``.
noise_sigma=0.1,
),
eval=dict(), # for compatibility
# other config
other=dict(
# Epsilon greedy with decay.
eps=dict(
# (str) Decay type. Support ['exp', 'linear'].
type='exp',
# (float) Epsilon start value.
start=0.95,
# (float) Epsilon end value.
end=0.1,
# (int) Decay length(env step)
decay=10000,
),
replay_buffer=dict(
# (int) Maximum size of replay buffer. Usually, larger buffer size is better.
replay_buffer_size=10000,
),
),
)
[docs] def default_model(self) -> Tuple[str, List[str]]:
"""
Overview:
Return this algorithm default neural network model setting for demonstration. ``__init__`` method will \
automatically call this method to get the default model setting and create model.
Returns:
- model_info (:obj:`Tuple[str, List[str]]`): The registered model name and model's import_names.
.. note::
The user can define and use customized network model but must obey the same inferface definition indicated \
by import_names path. For example about PDQN, its registered name is ``pdqn`` and the import_names is \
``ding.model.template.pdqn``.
"""
return 'pdqn', ['ding.model.template.pdqn']
[docs] def _init_learn(self) -> None:
"""
Overview:
Initialize the learn mode of policy, including related attributes and modules. For PDQN, it mainly \
contains two optimizers, algorithm-specific arguments such as nstep and gamma, main and target model.
This method will be called in ``__init__`` method if ``learn`` field is in ``enable_field``.
.. note::
For the member variables that need to be saved and loaded, please refer to the ``_state_dict_learn`` \
and ``_load_state_dict_learn`` methods.
.. note::
For the member variables that need to be monitored, please refer to the ``_monitor_vars_learn`` method.
.. note::
If you want to set some spacial member variables in ``_init_learn`` method, you'd better name them \
with prefix ``_learn_`` to avoid conflict with other modes, such as ``self._learn_attr1``.
"""
self._priority = self._cfg.priority
self._priority_IS_weight = self._cfg.priority_IS_weight
# Optimizer
self._dis_optimizer = Adam(
list(self._model.dis_head.parameters()) + list(self._model.cont_encoder.parameters()),
# this is very important to put cont_encoder.parameters in here.
lr=self._cfg.learn.learning_rate_dis
)
self._cont_optimizer = Adam(list(self._model.cont_head.parameters()), lr=self._cfg.learn.learning_rate_cont)
self._gamma = self._cfg.discount_factor
self._nstep = self._cfg.nstep
# use model_wrapper for specialized demands of different modes
self._target_model = copy.deepcopy(self._model)
self._target_model = model_wrap(
self._target_model,
wrapper_name='target',
update_type='momentum',
update_kwargs={'theta': self._cfg.learn.target_theta}
)
self._learn_model = model_wrap(self._model, wrapper_name='hybrid_argmax_sample')
self._learn_model.reset()
self._target_model.reset()
self.cont_train_cnt = 0
self.disc_train_cnt = 0
self.train_cnt = 0
[docs] def _forward_learn(self, data: Dict[str, Any]) -> Dict[str, Any]:
"""
Overview:
Policy forward function of learn mode (training policy and updating parameters). Forward means \
that the policy inputs some training batch data from the replay buffer and then returns the output \
result, including various training information such as loss, q value, target_q_value, priority.
Arguments:
- data (:obj:`List[Dict[int, Any]]`): The input data used for policy forward, including a batch of \
training samples. For each element in list, the key of the dict is the name of data items and the \
value is the corresponding data. Usually, the value is torch.Tensor or np.ndarray or there dict/list \
combinations. In the ``_forward_learn`` method, data often need to first be stacked in the batch \
dimension by some utility functions such as ``default_preprocess_learn``. \
For PDQN, each element in list is a dict containing at least the following keys: ``obs``, ``action``, \
``reward``, ``next_obs``, ``done``. Sometimes, it also contains other keys such as ``weight`` \
and ``value_gamma``.
Returns:
- info_dict (:obj:`Dict[str, Any]`): The information dict that indicated training result, which will be \
recorded in text log and tensorboard, values must be python scalar or a list of scalars. For the \
detailed definition of the dict, refer to the code of ``_monitor_vars_learn`` method.
.. note::
The input value can be torch.Tensor or dict/list combinations and current policy supports all of them. \
For the data type that not supported, the main reason is that the corresponding model does not support it. \
You can implement you own model rather than use the default model. For more information, please raise an \
issue in GitHub repo and we will continue to follow up.
.. note::
For more detailed examples, please refer to our unittest for PDQNPolicy: ``ding.policy.tests.test_pdqn``.
"""
data = default_preprocess_learn(
data,
use_priority=self._priority,
use_priority_IS_weight=self._cfg.priority_IS_weight,
ignore_done=self._cfg.learn.ignore_done,
use_nstep=True
)
if self._cuda:
data = to_device(data, self._device)
self.train_cnt += 1
# ================================
# Continuous args network forward
# ================================
if self.train_cnt == 1 or self.train_cnt % self._cfg.learn.update_circle in range(5, 10):
dis_loss = torch.Tensor([0])
td_error_per_sample = torch.Tensor([0])
target_q_value = torch.Tensor([0])
action_args = self._learn_model.forward(data['obs'], mode='compute_continuous')['action_args']
# Current q value (main model) for cont loss
discrete_inputs = {'state': data['obs'], 'action_args': action_args}
# with torch.no_grad():
q_pi_action_value = self._learn_model.forward(discrete_inputs, mode='compute_discrete')['logit']
cont_loss = -q_pi_action_value.sum(dim=-1).mean()
# ================================
# Continuous args network update
# ================================
self._cont_optimizer.zero_grad()
cont_loss.backward()
self._cont_optimizer.step()
# ====================
# Q-learning forward
# ====================
if self.train_cnt == 1 or self.train_cnt % self._cfg.learn.update_circle in range(0, 5):
cont_loss = torch.Tensor([0])
q_pi_action_value = torch.Tensor([0])
self._learn_model.train()
self._target_model.train()
# Current q value (main model)
discrete_inputs = {'state': data['obs'], 'action_args': data['action']['action_args']}
q_data_action_args_value = self._learn_model.forward(discrete_inputs, mode='compute_discrete')['logit']
# Target q value
with torch.no_grad():
next_action_args = self._learn_model.forward(data['next_obs'], mode='compute_continuous')['action_args']
next_action_args_cp = next_action_args.clone().detach()
next_discrete_inputs = {'state': data['next_obs'], 'action_args': next_action_args_cp}
target_q_value = self._target_model.forward(next_discrete_inputs, mode='compute_discrete')['logit']
# Max q value action (main model)
target_q_discrete_action = self._learn_model.forward(
next_discrete_inputs, mode='compute_discrete'
)['action']['action_type']
data_n = q_nstep_td_data(
q_data_action_args_value, target_q_value, data['action']['action_type'], target_q_discrete_action,
data['reward'], data['done'], data['weight']
)
value_gamma = data.get('value_gamma')
dis_loss, td_error_per_sample = q_nstep_td_error(
data_n, self._gamma, nstep=self._nstep, value_gamma=value_gamma
)
# ====================
# Q-learning update
# ====================
self._dis_optimizer.zero_grad()
dis_loss.backward()
self._dis_optimizer.step()
# =============
# after update
# =============
self._target_model.update(self._learn_model.state_dict())
return {
'cur_lr': self._dis_optimizer.defaults['lr'],
'q_loss': dis_loss.item(),
'total_loss': cont_loss.item() + dis_loss.item(),
'continuous_loss': cont_loss.item(),
'q_value': q_pi_action_value.mean().item(),
'priority': td_error_per_sample.abs().tolist(),
'reward': data['reward'].mean().item(),
'target_q_value': target_q_value.mean().item(),
}
[docs] def _state_dict_learn(self) -> Dict[str, Any]:
"""
Overview:
Return the state_dict of learn mode, usually including model, target model, discrete part optimizer, and \
continuous part optimizer.
Returns:
- state_dict (:obj:`Dict[str, Any]`): the dict of current policy learn state, for saving and restoring.
"""
return {
'model': self._learn_model.state_dict(),
'target_model': self._target_model.state_dict(),
'dis_optimizer': self._dis_optimizer.state_dict(),
'cont_optimizer': self._cont_optimizer.state_dict()
}
[docs] def _load_state_dict_learn(self, state_dict: Dict[str, Any]) -> None:
"""
Overview:
Load the state_dict variable into policy learn mode.
Arguments:
- state_dict (:obj:`Dict[str, Any]`): the dict of policy learn state saved before.
.. tip::
If you want to only load some parts of model, you can simply set the ``strict`` argument in \
load_state_dict to ``False``, or refer to ``ding.torch_utils.checkpoint_helper`` for more \
complicated operation.
"""
self._learn_model.load_state_dict(state_dict['model'])
self._target_model.load_state_dict(state_dict['target_model'])
self._dis_optimizer.load_state_dict(state_dict['dis_optimizer'])
self._cont_optimizer.load_state_dict(state_dict['cont_optimizer'])
[docs] def _init_collect(self) -> None:
"""
Overview:
Initialize the collect mode of policy, including related attributes and modules. For PDQN, it contains the \
collect_model to balance the exploration and exploitation with epsilon-greedy sample mechanism and \
continuous action mechanism, besides, other algorithm-specific arguments such as unroll_len and nstep are \
also initialized here.
This method will be called in ``__init__`` method if ``collect`` field is in ``enable_field``.
.. note::
If you want to set some spacial member variables in ``_init_collect`` method, you'd better name them \
with prefix ``_collect_`` to avoid conflict with other modes, such as ``self._collect_attr1``.
.. tip::
Some variables need to initialize independently in different modes, such as gamma and nstep in PDQN. This \
design is for the convenience of parallel execution of different policy modes.
"""
self._unroll_len = self._cfg.collect.unroll_len
self._gamma = self._cfg.discount_factor # necessary for parallel
self._nstep = self._cfg.nstep # necessary for parallel
self._collect_model = model_wrap(
self._model,
wrapper_name='action_noise',
noise_type='gauss',
noise_kwargs={
'mu': 0.0,
'sigma': self._cfg.collect.noise_sigma
},
noise_range=None
)
self._collect_model = model_wrap(self._collect_model, wrapper_name='hybrid_eps_greedy_multinomial_sample')
self._collect_model.reset()
[docs] def _forward_collect(self, data: Dict[int, Any], eps: float) -> Dict[int, Any]:
"""
Overview:
Policy forward function of collect mode (collecting training data by interacting with envs). Forward means \
that the policy gets some necessary data (mainly observation) from the envs and then returns the output \
data, such as the action to interact with the envs. Besides, this policy also needs ``eps`` argument for \
exploration, i.e., classic epsilon-greedy exploration strategy.
Arguments:
- data (:obj:`Dict[int, Any]`): The input data used for policy forward, including at least the obs. The \
key of the dict is environment id and the value is the corresponding data of the env.
- eps (:obj:`float`): The epsilon value for exploration.
Returns:
- output (:obj:`Dict[int, Any]`): The output data of policy forward, including at least the action and \
other necessary data for learn mode defined in ``self._process_transition`` method. The key of the \
dict is the same as the input data, i.e. environment id.
.. note::
The input value can be torch.Tensor or dict/list combinations and current policy supports all of them. \
For the data type that not supported, the main reason is that the corresponding model does not support it. \
You can implement you own model rather than use the default model. For more information, please raise an \
issue in GitHub repo and we will continue to follow up.
.. note::
For more detailed examples, please refer to our unittest for PDQNPolicy: ``ding.policy.tests.test_pdqn``.
"""
data_id = list(data.keys())
data = default_collate(list(data.values()))
if self._cuda:
data = to_device(data, self._device)
self._collect_model.eval()
with torch.no_grad():
action_args = self._collect_model.forward(data, 'compute_continuous', eps=eps)['action_args']
inputs = {'state': data, 'action_args': action_args.clone().detach()}
output = self._collect_model.forward(inputs, 'compute_discrete', eps=eps)
if self._cuda:
output = to_device(output, 'cpu')
output = default_decollate(output)
return {i: d for i, d in zip(data_id, output)}
[docs] def _get_train_sample(self, transitions: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
"""
Overview:
For a given trajectory (transitions, a list of transition) data, process it into a list of sample that \
can be used for training directly. In PDQN, a train sample is a processed transition. \
This method is usually used in collectors to execute necessary \
RL data preprocessing before training, which can help learner amortize revelant time consumption. \
In addition, you can also implement this method as an identity function and do the data processing \
in ``self._forward_learn`` method.
Arguments:
- transitions (:obj:`List[Dict[str, Any]`): The trajectory data (a list of transition), each element is \
the same format as the return value of ``self._process_transition`` method.
Returns:
- samples (:obj:`List[Dict[str, Any]]`): The processed train samples, each element is the similar format \
as input transitions, but may contain more data for training, such as nstep reward and target obs.
"""
transitions = get_nstep_return_data(transitions, self._nstep, gamma=self._gamma)
return get_train_sample(transitions, self._unroll_len)
[docs] def _process_transition(self, obs: torch.Tensor, policy_output: Dict[str, torch.Tensor],
timestep: namedtuple) -> Dict[str, torch.Tensor]:
"""
Overview:
Process and pack one timestep transition data into a dict, which can be directly used for training and \
saved in replay buffer. For PDQN, it contains obs, next_obs, action, reward, done and logit.
Arguments:
- obs (:obj:`torch.Tensor`): The env observation of current timestep, such as stacked 2D image in Atari.
- policy_output (:obj:`Dict[str, torch.Tensor]`): The output of the policy network with the observation \
as input. For PDQN, it contains the hybrid action and the logit (discrete part q_value) of the action.
- timestep (:obj:`namedtuple`): The execution result namedtuple returned by the environment step method, \
except all the elements have been transformed into tensor data. Usually, it contains the next obs, \
reward, done, info, etc.
Returns:
- transition (:obj:`Dict[str, torch.Tensor]`): The processed transition data of the current timestep.
"""
transition = {
'obs': obs,
'next_obs': timestep.obs,
'action': policy_output['action'],
'logit': policy_output['logit'],
'reward': timestep.reward,
'done': timestep.done,
}
return transition
[docs] def _init_eval(self) -> None:
"""
Overview:
Initialize the eval mode of policy, including related attributes and modules. For PDQN, it contains the \
eval model to greedily select action with argmax q_value mechanism.
This method will be called in ``__init__`` method if ``eval`` field is in ``enable_field``.
.. note::
If you want to set some spacial member variables in ``_init_eval`` method, you'd better name them \
with prefix ``_eval_`` to avoid conflict with other modes, such as ``self._eval_attr1``.
"""
self._eval_model = model_wrap(self._model, wrapper_name='hybrid_argmax_sample')
self._eval_model.reset()
[docs] def _forward_eval(self, data: Dict[int, Any]) -> Dict[int, Any]:
"""
Overview:
Policy forward function of eval mode (evaluation policy performance by interacting with envs). Forward \
means that the policy gets some necessary data (mainly observation) from the envs and then returns the \
action to interact with the envs.
Arguments:
- data (:obj:`Dict[int, Any]`): The input data used for policy forward, including at least the obs. The \
key of the dict is environment id and the value is the corresponding data of the env.
Returns:
- output (:obj:`Dict[int, Any]`): The output data of policy forward, including at least the action. The \
key of the dict is the same as the input data, i.e. environment id.
.. note::
The input value can be torch.Tensor or dict/list combinations and current policy supports all of them. \
For the data type that not supported, the main reason is that the corresponding model does not support it. \
You can implement you own model rather than use the default model. For more information, please raise an \
issue in GitHub repo and we will continue to follow up.
.. note::
For more detailed examples, please refer to our unittest for PDQNPolicy: ``ding.policy.tests.test_pdqn``.
"""
data_id = list(data.keys())
data = default_collate(list(data.values()))
if self._cuda:
data = to_device(data, self._device)
self._eval_model.eval()
with torch.no_grad():
action_args = self._eval_model.forward(data, mode='compute_continuous')['action_args']
inputs = {'state': data, 'action_args': action_args.clone().detach()}
output = self._eval_model.forward(inputs, mode='compute_discrete')
if self._cuda:
output = to_device(output, 'cpu')
output = default_decollate(output)
return {i: d for i, d in zip(data_id, output)}
[docs] def _monitor_vars_learn(self) -> List[str]:
"""
Overview:
Return the necessary keys for logging the return dict of ``self._forward_learn``. The logger module, such \
as text logger, tensorboard logger, will use these keys to save the corresponding data.
Returns:
- necessary_keys (:obj:`List[str]`): The list of the necessary keys to be logged.
"""
return ['cur_lr', 'total_loss', 'q_loss', 'continuous_loss', 'q_value', 'reward', 'target_q_value']