sketch of training from sim env

dreamer4/trainers.py

@@ -4,7 +4,7 @@ import torch
 from torch import is_tensor
 from torch.nn import Module
 from torch.optim import AdamW
-from torch.utils.data import Dataset, DataLoader
+from torch.utils.data import Dataset, TensorDataset, DataLoader
 
 from accelerate import Accelerator
 
@@ -12,7 +12,9 @@ from adam_atan2_pytorch import MuonAdamAtan2
 
 from dreamer4.dreamer4 import (
     VideoTokenizer,
-    DynamicsWorldModel
+    DynamicsWorldModel,
+    Experience,
+    combine_experiences
 )
 
 from ema_pytorch import EMA
@@ -317,3 +319,198 @@ class DreamTrainer(Module):
             self.value_head_optim.zero_grad()
 
         self.print('training complete')
+
+# training from sim
+
+class SimTrainer(Module):
+    def __init__(
+        self,
+        model: DynamicsWorldModel,
+        optim_klass = AdamW,
+        batch_size = 16,
+        generate_timesteps = 16,
+        learning_rate = 3e-4,
+        max_grad_norm = None,
+        epochs = 2,
+        weight_decay = 0.,
+        accelerate_kwargs: dict = dict(),
+        optim_kwargs: dict = dict(),
+        cpu = False,
+    ):
+        super().__init__()
+
+        self.accelerator = Accelerator(
+            cpu = cpu,
+            **accelerate_kwargs
+        )
+
+        self.model = model
+
+        optim_kwargs = dict(
+            lr = learning_rate,
+            weight_decay = weight_decay
+        )
+
+        self.policy_head_optim = AdamW(model.policy_head_parameters(), **optim_kwargs)
+        self.value_head_optim = AdamW(model.value_head_parameters(), **optim_kwargs)
+
+        self.max_grad_norm = max_grad_norm
+
+        self.epochs = epochs
+        self.batch_size = batch_size
+
+        self.generate_timesteps = generate_timesteps
+
+        self.unwrapped_model = self.model
+
+        (
+            self.model,
+            self.policy_head_optim,
+            self.value_head_optim,
+        ) = self.accelerator.prepare(
+            self.model,
+            self.policy_head_optim,
+            self.value_head_optim
+        )
+
+    @property
+    def device(self):
+        return self.accelerator.device
+
+    @property
+    def unwrapped_model(self):
+        return self.accelerator.unwrap_model(self.model)
+
+    def print(self, *args, **kwargs):
+        return self.accelerator.print(*args, **kwargs)
+
+    def learn(
+        self,
+        experience: Experience
+    ):
+
+        step_size = experience.step_size
+        agent_index = experience.agent_index
+
+        latents = experience.latents
+        old_values = experience.values
+        rewards = experience.rewards
+
+        discrete_actions, continuous_actions = experience.actions
+        discrete_log_probs, continuous_log_probs = experience.log_probs
+
+        # handle empties
+
+        empty_tensor = torch.empty_like(rewards)
+
+        has_discrete = exists(discrete_actions)
+        has_continuous = exists(continuous_actions)
+
+        discrete_actions = default(discrete_actions, empty_tensor)
+        continuous_actions = default(continuous_actions, empty_tensor)
+
+        discrete_log_probs = default(discrete_log_probs, empty_tensor)
+        continuous_log_probs = default(continuous_log_probs, empty_tensor)
+
+        # create the dataset and dataloader
+
+        dataset = TensorDataset(
+            latents,
+            discrete_actions,
+            continuous_actions,
+            discrete_log_probs,
+            continuous_log_probs,
+            old_values,
+            rewards
+        )
+
+        dataloader = DataLoader(dataset, batch_size = self.batch_size, shuffle = True)
+
+        for epoch in range(self.epochs):
+
+            for (
+                latents,
+                discrete_actions,
+                continuous_actions,
+                discrete_log_probs,
+                continuous_log_probs,
+                old_values,
+                rewards
+            ) in dataloader:
+
+                actions = (
+                    discrete_actions if has_discrete else None,
+                    continuous_actions if has_continuous else None
+                )
+
+                log_probs = (
+                    discrete_log_probs if has_discrete else None,
+                    continuous_log_probs if has_continuous else None
+                )
+
+                batch_experience = Experience(
+                    latents = latents,
+                    actions = actions,
+                    log_probs = log_probs,
+                    values = old_values,
+                    rewards = rewards,
+                    step_size = step_size,
+                    agent_index = agent_index
+                )
+
+                policy_head_loss, value_head_loss = self.model.learn_from_experience(batch_experience)
+
+                self.print(f'policy head loss: {policy_head_loss.item():.3f} | value head loss: {value_head_loss.item():.3f}')
+
+                # update policy head
+
+                self.accelerator.backward(policy_head_loss)
+
+                if exists(self.max_grad_norm):
+                    self.accelerator.clip_grad_norm_(self.model.policy_head_parameters()(), self.max_grad_norm)
+
+                self.policy_head_optim.step()
+                self.policy_head_optim.zero_grad()
+
+                # update value head
+
+                self.accelerator.backward(value_head_loss)
+
+                if exists(self.max_grad_norm):
+                    self.accelerator.clip_grad_norm_(self.model.value_head_parameters(), self.max_grad_norm)
+
+                self.value_head_optim.step()
+                self.value_head_optim.zero_grad()
+
+        self.print('training complete')
+
+    def forward(
+        self,
+        env,
+        num_episodes = 50000,
+        max_experiences_before_learn = 8,
+        env_is_vectorized = False
+    ):
+
+        for _ in range(num_episodes):
+
+            total_experience = 0
+            experiences = []
+
+            while total_experience < max_experiences_before_learn:
+
+                experience = self.unwrapped_model.interact_with_env(env, env_is_vectorized = env_is_vectorized)
+
+                num_experience = experience.video.shape[0]
+
+                total_experience += num_experience
+
+                experiences.append(experience)
+
+            combined_experiences = combine_experiences(experiences)
+
+            self.learn(combined_experiences)
+
+            experiences.clear()
+
+        self.print('training complete')

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "dreamer4"
-version = "0.0.67"
+version = "0.0.69"
 description = "Dreamer 4"
 authors = [
     { name = "Phil Wang", email = "lucidrains@gmail.com" }

tests/test_dreamer.py

@@ -641,6 +641,8 @@ def test_online_rl(
 
     mock_env = MockEnv((256, 256), vectorized = vectorized, num_envs = 4)
 
+    # manually
+
     one_experience = world_model_and_policy.interact_with_env(mock_env, max_timesteps = 16, env_is_vectorized = vectorized)
     another_experience = world_model_and_policy.interact_with_env(mock_env, max_timesteps = 16, env_is_vectorized = vectorized)
 
@@ -650,3 +652,15 @@ def test_online_rl(
 
     actor_loss.backward()
     critic_loss.backward()
+
+    # with trainer
+
+    from dreamer4.trainers import SimTrainer
+
+    trainer = SimTrainer(
+        world_model_and_policy,
+        batch_size = 4,
+        cpu = True
+    )
+
+    trainer(mock_env, num_episodes = 2, env_is_vectorized = vectorized)