Merge pull request #1 from vmoens/refactor_tcq

Refactor TQC

.github/unittest/linux_libs/scripts_d4rl/environment.yml

@@ -17,3 +17,4 @@ dependencies:
     - pyyaml
     - scipy
     - hydra-core
+    - cython<3

docs/source/reference/data.rst

@@ -43,6 +43,7 @@ We also give users the ability to compose a replay buffer using the following co
     Writer
     RoundRobinWriter
     TensorDictRoundRobinWriter
+    TensorDictMaxValueWriter
 
 Storage choice is very influential on replay buffer sampling latency, especially in distributed reinforcement learning settings with larger data volumes.
 :class:`LazyMemmapStorage` is highly advised in distributed settings with shared storage due to the lower serialisation cost of MemmapTensors as well as the ability to specify file storage locations for improved node failure recovery.

docs/source/reference/objectives.rst

@@ -138,7 +138,7 @@ CQL
     CQLLoss
 
 DT
-----
+--
 
 .. autosummary::
     :toctree: generated/
@@ -148,14 +148,23 @@ DT
     OnlineDTLoss
 
 TD3
-----
+---
 
 .. autosummary::
     :toctree: generated/
     :template: rl_template_noinherit.rst
 
     TD3Loss
 
+TQC
+---
+
+.. autosummary::
+    :toctree: generated/
+    :template: rl_template_noinherit.rst
+
+    TQCLoss
+
 PPO
 ---
 

examples/tqc/tqc.py

@@ -29,6 +29,7 @@
 """
 
 import time
+
 import hydra
 import numpy as np
 import torch
@@ -57,7 +58,7 @@ def main(cfg: "DictConfig"):  # noqa: F821
     exp_name = generate_exp_name("SAC", cfg.env.exp_name)
     logger = None
     # TO-DO: Add logging back in before pushing to git repo
-    #if cfg.logger.backend:
+    # if cfg.logger.backend:
     #    logger = get_logger(
     #        logger_type=cfg.logger.backend,
     #        logger_name="sac_logging/wandb",
@@ -190,7 +191,9 @@ def main(cfg: "DictConfig"):  # noqa: F821
                 episode_length
             )
         if collected_frames >= init_random_frames:
-            metrics_to_log["train/critic_loss"] = losses.get("loss_critic").mean().item()
+            metrics_to_log["train/critic_loss"] = (
+                losses.get("loss_critic").mean().item()
+            )
             metrics_to_log["train/actor_loss"] = losses.get("loss_actor").mean().item()
             metrics_to_log["train/alpha_loss"] = losses.get("loss_alpha").mean().item()
             metrics_to_log["train/alpha"] = loss_td["alpha"].item()

examples/tqc/utils.py

@@ -5,23 +5,27 @@
 
 import tempfile
 from contextlib import nullcontext
+from typing import Tuple
+
 import torch
-import numpy as np
 from tensordict.nn import InteractionType, TensorDictModule
 from tensordict.nn.distributions import NormalParamExtractor
+from tensordict.tensordict import TensorDict, TensorDictBase
 from torch import nn, optim
 from torchrl.collectors import SyncDataCollector
-from torchrl.data import TensorDictPrioritizedReplayBuffer, TensorDictReplayBuffer
+from torchrl.data import (
+    CompositeSpec,
+    TensorDictPrioritizedReplayBuffer,
+    TensorDictReplayBuffer,
+)
 from torchrl.data.replay_buffers.storages import LazyMemmapStorage
 from torchrl.envs import Compose, DoubleToFloat, EnvCreator, ParallelEnv, TransformedEnv
 from torchrl.envs.libs.gym import GymEnv, set_gym_backend
 from torchrl.envs.transforms import InitTracker, RewardSum, StepCounter
 from torchrl.envs.utils import ExplorationType, set_exploration_type
-from torchrl.modules import MLP, ProbabilisticActor, ValueOperator, ActorCriticWrapper
+from torchrl.modules import ActorCriticWrapper, MLP, ProbabilisticActor, ValueOperator
 from torchrl.modules.distributions import TanhNormal
-from torchrl.objectives import SoftUpdate
-from torchrl.data import CompositeSpec
-from torchrl.objectives.common import LossModule
+from torchrl.objectives import SoftUpdate, TQCLoss
 from torchrl.objectives.utils import (
     _cache_values,
     _GAMMA_LMBDA_DEPREC_WARNING,
@@ -30,8 +34,6 @@
     ValueEstimators,
 )
 from torchrl.objectives.value import TD0Estimator, TD1Estimator, TDLambdaEstimator
-from tensordict.tensordict import TensorDict, TensorDictBase
-from typing import Tuple
 
 
 # ====================================================================
@@ -100,17 +102,17 @@ def make_collector(cfg, train_env, actor_model_explore):
 
 
 def make_replay_buffer(
-        batch_size,
-        prb=False,
-        buffer_size=1_000_000,
-        buffer_scratch_dir=None,
-        device="cpu",
-        prefetch=3,
+    batch_size,
+    prb=False,
+    buffer_size=1_000_000,
+    buffer_scratch_dir=None,
+    device="cpu",
+    prefetch=3,
 ):
     with (
-            tempfile.TemporaryDirectory()
-            if buffer_scratch_dir is None
-            else nullcontext(buffer_scratch_dir)
+        tempfile.TemporaryDirectory()
+        if buffer_scratch_dir is None
+        else nullcontext(buffer_scratch_dir)
     ) as scratch_dir:
         if prb:
             replay_buffer = TensorDictPrioritizedReplayBuffer(
@@ -155,13 +157,15 @@ def __init__(self, cfg):
         }
         for i in range(cfg.network.n_nets):
             net = MLP(**qvalue_net_kwargs)
-            self.add_module(f'critic_net_{i}', net)
+            self.add_module(f"critic_net_{i}", net)
             self.nets.append(net)
 
     def forward(self, *inputs: Tuple[torch.Tensor]) -> torch.Tensor:
         if len(inputs) > 1:
             inputs = (torch.cat([*inputs], -1),)
-        quantiles = torch.stack(tuple(net(*inputs) for net in self.nets), dim=-2)  # batch x n_nets x n_quantiles
+        quantiles = torch.stack(
+            tuple(net(*inputs) for net in self.nets), dim=-2
+        )  # batch x n_nets x n_quantiles
         return quantiles
 
 
@@ -239,172 +243,26 @@ def make_tqc_agent(cfg, train_env, eval_env, device):
     return model, model[0]
 
 
-# ====================================================================
-# Quantile Huber Loss
-# -------------------
-
-
-def quantile_huber_loss_f(quantiles, samples):
-    """
-    Quantile Huber loss from the original PyTorch TQC implementation.
-    See: https://github.com/SamsungLabs/tqc_pytorch/blob/master/tqc/functions.py
-
-    quantiles is assumed to be of shape [batch size, n_nets, n_quantiles]
-    samples is assumed to be of shape [batch size, n_samples]
-    Arbitrary batch sizes are allowed.
-    """
-    pairwise_delta = samples[..., None, None, :] - quantiles[..., None]  # batch x n_nets x n_quantiles x n_samples
-    abs_pairwise_delta = torch.abs(pairwise_delta)
-    huber_loss = torch.where(abs_pairwise_delta > 1,
-                             abs_pairwise_delta - 0.5,
-                             pairwise_delta ** 2 * 0.5)
-    n_quantiles = quantiles.shape[-1]
-    tau = torch.arange(n_quantiles, device=quantiles.device).float() / n_quantiles + 1 / 2 / n_quantiles
-    loss = (torch.abs(tau[..., None, :, None] - (pairwise_delta < 0).float()) * huber_loss).mean()
-    return loss
-
-
 # ====================================================================
 # TQC Loss
 # --------
 
-class TQCLoss(LossModule):
-    def __init__(
-            self,
-            actor_network,
-            qvalue_network,
-            gamma,
-            top_quantiles_to_drop,
-            alpha_init,
-            device
-    ):
-        super().__init__()
-
-        self.convert_to_functional(
-            actor_network,
-            "actor",
-            create_target_params=False,
-            funs_to_decorate=["forward", "get_dist"],
-        )
-
-        self.convert_to_functional(
-            qvalue_network,
-            "critic",
-            create_target_params=True  # Create a target critic network
-        )
-
-        self.device = device
-        self.log_alpha = torch.tensor([np.log(alpha_init)], requires_grad=True, device=self.device)
-        self.gamma = gamma
-        self.top_quantiles_to_drop = top_quantiles_to_drop
-
-        # Compute target entropy
-        action_spec = getattr(self.actor, "spec", None)
-        if action_spec is None:
-            print("Could not deduce action spec from actor network.")
-        if not isinstance(action_spec, CompositeSpec):
-            action_spec = CompositeSpec({"action": action_spec})
-        action_container_len = len(action_spec.shape)
-        self.target_entropy = -float(action_spec["action"].shape[action_container_len:].numel())
-
-    def value_loss(self, tensordict):
-        td_next = tensordict.get("next")
-        reward = td_next.get("reward")
-        not_done = tensordict.get("done").logical_not()
-        alpha = torch.exp(self.log_alpha)
-
-        # Q-loss
-        with torch.no_grad():
-            # get policy action
-            self.actor(td_next, params=self.actor_params)
-            self.critic(td_next, params=self.target_critic_params)
-
-            next_log_pi = td_next.get("sample_log_prob")
-            next_log_pi = torch.unsqueeze(next_log_pi, dim=-1)
-
-            # compute and cut quantiles at the next state
-            next_z = td_next.get("state_action_value")
-            sorted_z, _ = torch.sort(next_z.reshape(*tensordict.batch_size, -1))
-            sorted_z_part = sorted_z[..., :-self.top_quantiles_to_drop]
-
-            # compute target
-            # --- Note ---
-            # This is computed manually here, since the built-in value estimators in the library
-            # currently do not support a critic of a shape different from the reward.
-            # ------------
-            target = reward + not_done * self.gamma * (sorted_z_part - alpha * next_log_pi)
-
-        self.critic(tensordict, params=self.critic_params)
-        cur_z = tensordict.get("state_action_value")
-        critic_loss = quantile_huber_loss_f(cur_z, target)
-        return critic_loss
-
-    def actor_loss(self, tensordict):
-        alpha = torch.exp(self.log_alpha)
-        self.actor(tensordict, params=self.actor_params)
-        self.critic(tensordict, params=self.critic_params)
-        new_log_pi = tensordict.get("sample_log_prob")
-        actor_loss = (alpha * new_log_pi - tensordict.get("state_action_value").mean(-1).mean(-1, keepdim=True)).mean()
-        return actor_loss, new_log_pi
-
-    def alpha_loss(self, log_prob):
-        alpha_loss = -self.log_alpha * (log_prob + self.target_entropy).detach().mean()
-        return alpha_loss
-
-    def entropy(self, tensordict):
-        with set_exploration_type(ExplorationType.RANDOM):
-            dist = self.actor.get_dist(
-                tensordict,
-                params=self.actor_params,
-            )
-            a_reparm = dist.rsample()
-        log_prob = dist.log_prob(a_reparm).detach()
-        entropy = -log_prob.mean()
-        return entropy
-
-    def forward(self, tensordict: TensorDictBase) -> TensorDictBase:
-        alpha = torch.exp(self.log_alpha)
-        critic_loss = self.value_loss(tensordict)
-        actor_loss, log_prob = self.actor_loss(tensordict)  # Compute actor loss AFTER critic loss
-        alpha_loss = self.alpha_loss(log_prob)
-        entropy = self.entropy(tensordict)
-
-        return TensorDict(
-            {
-                "loss_critic": critic_loss,
-                "loss_actor": actor_loss,
-                "loss_alpha": alpha_loss,
-                "alpha": alpha,
-                "entropy": entropy,
-            },
-            batch_size=[]
-        )
-
-    def make_value_estimator(self, value_type: ValueEstimators = None, **hyperparams):
-        """
-        This is a dummy function, which simply checks if the value type is TD0 and raises
-        an error if the value type is different. As of writing of this, the value estimators
-        in the library do not support a critic shape different from the reward state, which
-        is however necessary by construction for TQC. Therefore, this function does not
-        actually construct a value estimator, and the value is estimated "by hand" in the
-        value_loss function above.
-        """
-        if value_type is not ValueEstimators.TD0:
-            raise NotImplementedError(f"Value type {value_type} is not currently implemented.")
-
 
 def make_loss_module(cfg, model):
     """Make loss module and target network updater."""
     # Create TQC loss
+    top_quantiles_to_drop = (
+        cfg.network.top_quantiles_to_drop_per_net * cfg.network.n_nets
+    )
     loss_module = TQCLoss(
         actor_network=model[0],
         qvalue_network=model[1],
-        device=cfg.network.device,
-        gamma=cfg.optim.gamma,
-        top_quantiles_to_drop=cfg.network.top_quantiles_to_drop_per_net * cfg.network.n_nets,
-        alpha_init=cfg.optim.alpha_init
+        top_quantiles_to_drop=top_quantiles_to_drop,
+        alpha_init=cfg.optim.alpha_init,
+    )
+    loss_module.make_value_estimator(
+        value_type=ValueEstimators.TD0, gamma=cfg.optim.gamma
     )
-    loss_module.make_value_estimator(value_type=ValueEstimators.TD0)
 
     # Define Target Network Updater
     target_net_updater = SoftUpdate(loss_module, eps=cfg.optim.target_update_polyak)