This commit is contained in:
allenzren
2024-09-03 21:03:27 -04:00
commit 8293b0936b
282 changed files with 34664 additions and 0 deletions
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"""
Advantage-weighted regression (AWR) for Gaussian policy.
"""
import torch
import logging
from model.rl.gaussian_rwr import RWR_Gaussian
log = logging.getLogger(__name__)
class AWR_Gaussian(RWR_Gaussian):
def __init__(
self,
actor,
critic,
**kwargs,
):
super().__init__(actor=actor, **kwargs)
self.critic = critic.to(self.device)
def loss_critic(self, obs, advantages):
# get advantage
adv = self.critic(obs)
# Update critic
loss_critic = torch.mean((adv - advantages) ** 2)
return loss_critic
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"""
PPO for Gaussian policy.
"""
from typing import Optional
import torch
from model.rl.gaussian_vpg import VPG_Gaussian
class PPO_Gaussian(VPG_Gaussian):
def __init__(
self,
clip_ploss_coef: float,
clip_vloss_coef: Optional[float] = None,
norm_adv: Optional[bool] = True,
**kwargs,
):
super().__init__(**kwargs)
# Whether to normalize advantages within batch
self.norm_adv = norm_adv
# Clipping value for policy loss
self.clip_ploss_coef = clip_ploss_coef
# Clipping value for value loss
self.clip_vloss_coef = clip_vloss_coef
def loss(
self,
obs,
actions,
returns,
oldvalues,
advantages,
oldlogprobs,
use_bc_loss=False,
):
"""
PPO loss
obs: (B, obs_step, obs_dim)
actions: (B, horizon_step, action_dim)
returns: (B, )
values: (B, )
advantages: (B,)
oldlogprobs: (B, )
"""
newlogprobs, entropy, std = self.get_logprobs(obs, actions)
newlogprobs = newlogprobs.clamp(min=-5, max=2)
oldlogprobs = oldlogprobs.clamp(min=-5, max=2)
entropy_loss = -entropy
# get ratio
logratio = newlogprobs - oldlogprobs
ratio = logratio.exp()
# get kl difference and whether value clipped
with torch.no_grad():
approx_kl = ((ratio - 1) - logratio).nanmean()
clipfrac = (
((ratio - 1.0).abs() > self.clip_ploss_coef).float().mean().item()
)
# normalize advantages
if self.norm_adv:
advantages = (advantages - advantages.mean()) / (advantages.std() + 1e-8)
# Policy loss with clipping
pg_loss1 = -advantages * ratio
pg_loss2 = -advantages * torch.clamp(
ratio, 1 - self.clip_ploss_coef, 1 + self.clip_ploss_coef
)
pg_loss = torch.max(pg_loss1, pg_loss2).mean()
# Value loss optionally with clipping
newvalues = self.critic(obs).view(-1)
if self.clip_vloss_coef is not None:
v_loss_unclipped = (newvalues - returns) ** 2
v_clipped = oldvalues + torch.clamp(
newvalues - oldvalues,
-self.clip_vloss_coef,
self.clip_vloss_coef,
)
v_loss_clipped = (v_clipped - returns) ** 2
v_loss_max = torch.max(v_loss_unclipped, v_loss_clipped)
v_loss = 0.5 * v_loss_max.mean()
else:
v_loss = 0.5 * ((newvalues - returns) ** 2).mean()
bc_loss = 0.0
if use_bc_loss:
# See Eqn. 2 of https://arxiv.org/pdf/2403.03949.pdf
# Give a reward for maximizing probability of teacher policy's action with current policy.
# Actions are chosen along trajectory induced by current policy.
# Get counterfactual teacher actions
samples = self.forward(
cond=obs.float()
.unsqueeze(1)
.to(self.device), # B x horizon=1 x obs_dim
deterministic=False,
use_base_policy=True,
)
# Get logprobs of teacher actions under this policy
bc_logprobs, _, _ = self.get_logprobs(obs, samples, use_base_policy=False)
bc_logprobs = bc_logprobs.clamp(min=-5, max=2)
bc_loss = -bc_logprobs.mean()
return (
pg_loss,
entropy_loss,
v_loss,
clipfrac,
approx_kl.item(),
ratio.mean().item(),
bc_loss,
std.item(),
)
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"""
Reward-weighted regression (RWR) for Gaussian policy.
"""
import torch
import logging
from model.common.gaussian import GaussianModel
import torch.distributions as D
log = logging.getLogger(__name__)
class RWR_Gaussian(GaussianModel):
def __init__(
self,
actor,
randn_clip_value=10,
**kwargs,
):
super().__init__(network=actor, **kwargs)
# assign actor
self.actor = self.network
# Clip sampled randn (from standard deviation) such that the sampled action is not too far away from mean
self.randn_clip_value = randn_clip_value
# override
def loss(self, actions, obs, reward_weights):
cond = obs
B = cond.shape[0]
means, scales = self.network(cond)
dist = D.Normal(loc=means, scale=scales)
log_prob = dist.log_prob(actions.view(B, -1)).mean(-1)
log_prob = log_prob * reward_weights
log_prob = -log_prob.mean()
return log_prob
# override
@torch.no_grad()
def forward(self, cond, deterministic=False, **kwargs):
"""
Args:
cond: (batch_size, horizon, obs_dim)
Return:
actions: (batch_size, horizon_steps, transition_dim)
"""
B = cond.shape[0]
actions = super().forward(
cond=cond.view(B, -1),
deterministic=deterministic,
randn_clip_value=self.randn_clip_value,
)
return actions
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"""
Policy gradient for Gaussian policy
"""
import torch
from copy import deepcopy
import logging
from model.common.gaussian import GaussianModel
class VPG_Gaussian(GaussianModel):
def __init__(
self,
actor,
critic,
cond_steps=1,
randn_clip_value=10,
network_path=None,
**kwargs,
):
super().__init__(network=actor, **kwargs)
self.cond_steps = cond_steps
self.randn_clip_value = randn_clip_value
# Value function for obs - simple MLP
self.critic = critic.to(self.device)
if network_path is not None:
checkpoint = torch.load(
network_path, map_location=self.device, weights_only=True
)
self.load_state_dict(
checkpoint["model"],
strict=False,
)
logging.info("Loaded actor from %s", network_path)
# Re-name network to actor
self.actor_ft = actor
# Save a copy of original actor
self.actor = deepcopy(actor)
for param in self.actor.parameters():
param.requires_grad = False
def get_logprobs(
self,
cond,
actions,
use_base_policy=False,
):
B, T, D = actions.shape
if not isinstance(cond, dict):
cond = cond.view(B, -1)
dist = self.forward_train(
cond,
deterministic=False,
network_override=self.actor if use_base_policy else None,
)
log_prob = dist.log_prob(actions.view(B, -1))
log_prob = log_prob.mean(-1)
entropy = dist.entropy().mean()
std = dist.scale.mean()
return log_prob, entropy, std
def loss(self, obs, actions, reward):
raise NotImplementedError
@torch.no_grad()
def forward(
self,
cond,
deterministic=False,
use_base_policy=False,
):
if isinstance(cond, dict):
B = cond["state"].shape[0]
else:
B = cond.shape[0]
cond = cond.view(B, -1)
return super().forward(
cond=cond,
deterministic=deterministic,
randn_clip_value=self.randn_clip_value,
network_override=self.actor if use_base_policy else None,
)
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"""
PPO for GMM policy.
"""
from typing import Optional
import torch
from model.rl.gmm_vpg import VPG_GMM
class PPO_GMM(VPG_GMM):
def __init__(
self,
clip_ploss_coef: float,
clip_vloss_coef: Optional[float] = None,
norm_adv: Optional[bool] = True,
**kwargs,
):
super().__init__(**kwargs)
# Whether to normalize advantages within batch
self.norm_adv = norm_adv
# Clipping value for policy loss
self.clip_ploss_coef = clip_ploss_coef
# Clipping value for value loss
self.clip_vloss_coef = clip_vloss_coef
def loss(
self,
obs,
actions,
returns,
oldvalues,
advantages,
oldlogprobs,
**kwargs,
):
"""
PPO loss
obs: (B, obs_step, obs_dim)
actions: (B, horizon_step, action_dim)
returns: (B, )
values: (B, )
advantages: (B,)
oldlogprobs: (B, )
"""
newlogprobs, entropy, std = self.get_logprobs(obs, actions)
newlogprobs = newlogprobs.clamp(min=-5, max=2)
oldlogprobs = oldlogprobs.clamp(min=-5, max=2)
entropy_loss = -entropy.mean()
# get ratio
logratio = newlogprobs - oldlogprobs
ratio = logratio.exp()
# get kl difference and whether value clipped
with torch.no_grad():
approx_kl = ((ratio - 1) - logratio).nanmean()
clipfrac = (
((ratio - 1.0).abs() > self.clip_ploss_coef).float().mean().item()
)
# normalize advantages
if self.norm_adv:
advantages = (advantages - advantages.mean()) / (advantages.std() + 1e-8)
# Policy loss with clipping
pg_loss1 = -advantages * ratio
pg_loss2 = -advantages * torch.clamp(
ratio, 1 - self.clip_ploss_coef, 1 + self.clip_ploss_coef
)
pg_loss = torch.max(pg_loss1, pg_loss2).mean()
# Value loss optionally with clipping
newvalues = self.critic(obs).view(-1)
if self.clip_vloss_coef is not None:
v_loss_unclipped = (newvalues - returns) ** 2
v_clipped = oldvalues + torch.clamp(
newvalues - oldvalues,
-self.clip_vloss_coef,
self.clip_vloss_coef,
)
v_loss_clipped = (v_clipped - returns) ** 2
v_loss_max = torch.max(v_loss_unclipped, v_loss_clipped)
v_loss = 0.5 * v_loss_max.mean()
else:
v_loss = 0.5 * ((newvalues - returns) ** 2).mean()
bc_loss = 0
return (
pg_loss,
entropy_loss,
v_loss,
clipfrac,
approx_kl.item(),
ratio.mean().item(),
bc_loss,
std.item(),
)
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import torch
import logging
from model.common.gmm import GMMModel
class VPG_GMM(GMMModel):
def __init__(
self,
actor,
critic,
cond_steps=1,
network_path=None,
**kwargs,
):
super().__init__(network=actor, **kwargs)
self.cond_steps = cond_steps
# Re-name network to actor
self.actor_ft = actor
# Value function for obs - simple MLP
self.critic = critic.to(self.device)
if network_path is not None:
checkpoint = torch.load(
network_path, map_location=self.device, weights_only=True
)
self.load_state_dict(
checkpoint["model"],
strict=False,
)
logging.info("Loaded actor from %s", network_path)
def get_logprobs(
self,
cond,
actions,
):
B, T, D = actions.shape
dist, entropy, std = self.forward_train(
cond.view(B, -1),
deterministic=False,
)
log_prob = dist.log_prob(actions.view(B, -1))
return log_prob, entropy, std
def loss(self, obs, chains, reward):
raise NotImplementedError
# override to diffuse over action only
@torch.no_grad()
def forward(self, cond, deterministic=False):
B = cond.shape[0]
return super().forward(
cond=cond.view(B, -1),
deterministic=deterministic,
)