luchris429 / purejaxrl Goto Github PK

total_timesteps = 10_000
num_minibatches = 32
num_steps = 128
num_envs = 4
num_epochs = 10
lr = 0.1
num_updates = total_timesteps // num_steps // num_envs

def linear_schedule_purejaxrl(count):
    frac = 1.0 - (count // (num_minibatches * num_epochs)) / num_updates
    return lr * frac

def linear_schedule(count):
    frac = 1.0 - count / (num_epochs * num_minibatches * num_updates)
    return lr * frac


total_gradient_updates = (num_minibatches * num_epochs) * num_updates

plt.plot([linear_schedule(i) for i in range(1, total_gradient_updates + 1)], label="linear")
plt.plot([linear_schedule_purejaxrl(i) for i in range(1, total_gradient_updates + 1)], label="purejaxrl")
plt.legend()
plt.xlabel("Update")
plt.ylabel("Learning Rate")

from typing import NamedTuple, Sequence

import distrax
import flax.linen as nn
import gymnax
import jax
import jax.numpy as jnp
import numpy as np
import optax
from flax.linen.initializers import constant, orthogonal
from flax.training.train_state import TrainState
from purejaxrl.wrappers import FlattenObservationWrapper, LogWrapper
import wandb

from jax import config
#config.update("jax_disable_jit", True)

class ActorCritic(nn.Module):
    action_dim: Sequence[int]
    activation: str = "tanh"

    @nn.compact
    def __call__(self, x):
        if self.activation == "relu":
            activation = nn.relu
        else:
            activation = nn.tanh
        actor_mean = nn.Dense(
            64, kernel_init=orthogonal(np.sqrt(2)), bias_init=constant(0.0)
        )(x)
        actor_mean = activation(actor_mean)
        actor_mean = nn.Dense(
            64, kernel_init=orthogonal(np.sqrt(2)), bias_init=constant(0.0)
        )(actor_mean)
        actor_mean = activation(actor_mean)
        actor_mean = nn.Dense(
            self.action_dim, kernel_init=orthogonal(0.01), bias_init=constant(0.0)
        )(actor_mean)
        pi = distrax.Categorical(logits=actor_mean)

        critic = nn.Dense(
            64, kernel_init=orthogonal(np.sqrt(2)), bias_init=constant(0.0)
        )(x)
        critic = activation(critic)
        critic = nn.Dense(
            64, kernel_init=orthogonal(np.sqrt(2)), bias_init=constant(0.0)
        )(critic)
        critic = activation(critic)
        critic = nn.Dense(1, kernel_init=orthogonal(1.0), bias_init=constant(0.0))(
            critic
        )

        return pi, jnp.squeeze(critic, axis=-1)


class Transition(NamedTuple):
    done: jnp.ndarray
    action: jnp.ndarray
    value: jnp.ndarray
    reward: jnp.ndarray
    log_prob: jnp.ndarray
    obs: jnp.ndarray
    info: jnp.ndarray


def make_train(config):
    config["NUM_UPDATES"] = (
        config["TOTAL_TIMESTEPS"] // config["NUM_STEPS"] // config["NUM_ENVS"]
    )
    config["MINIBATCH_SIZE"] = (
        config["NUM_ENVS"] * config["NUM_STEPS"] // config["NUM_MINIBATCHES"]
    )
    env, env_params = gymnax.make(config["ENV_NAME"])
    env = FlattenObservationWrapper(env)
    env = LogWrapper(env)

    def linear_schedule(count):
        frac = (
            1.0
            - (count // (config["NUM_MINIBATCHES"] * config["UPDATE_EPOCHS"]))
            / config["NUM_UPDATES"]
        )
        return config["LR"] * frac

    def train(rng):
        # INIT NETWORK
        network = ActorCritic(
            env.action_space(env_params).n, activation=config["ACTIVATION"]
        )
        rng, _rng = jax.random.split(rng)
        init_x = jnp.zeros(env.observation_space(env_params).shape)
        network_params = network.init(_rng, init_x)
        if config["ANNEAL_LR"]:
            tx = optax.chain(
                optax.clip_by_global_norm(config["MAX_GRAD_NORM"]),
                optax.adam(learning_rate=linear_schedule, eps=1e-5),
            )
        else:
            tx = optax.chain(
                optax.clip_by_global_norm(config["MAX_GRAD_NORM"]),
                optax.adam(config["LR"], eps=1e-5),
            )
        train_state = TrainState.create(
            apply_fn=network.apply,
            params=network_params,
            tx=tx,
        )

        # INIT ENV
        rng, _rng = jax.random.split(rng)
        reset_rng = jax.random.split(_rng, config["NUM_ENVS"])
        obsv, env_state = jax.vmap(env.reset, in_axes=(0, None))(reset_rng, env_params)

        # TRAIN LOOP
        def _update_step(runner_state, unused):
            # COLLECT TRAJECTORIES
            def _env_step(runner_state, unused):
                train_state, time_state, env_state, last_obs, rng = runner_state

                # SELECT ACTION
                rng, _rng = jax.random.split(rng)
                pi, value = network.apply(train_state.params, last_obs)
                action = pi.sample(seed=_rng)
                log_prob = pi.log_prob(action)

                # STEP ENV
                rng, _rng = jax.random.split(rng)
                rng_step = jax.random.split(_rng, config["NUM_ENVS"])
                obsv, env_state, reward, done, info = jax.vmap(
                    env.step, in_axes=(0, 0, 0, None)
                )(rng_step, env_state, action, env_params)
                transition = Transition(
                    done, action, value, reward, log_prob, last_obs, info
                )
                runner_state = (train_state, time_state, env_state, obsv, rng)
                return runner_state, transition

            runner_state, traj_batch = jax.lax.scan(
                _env_step, runner_state, None, config["NUM_STEPS"]
            )

            # CALCULATE ADVANTAGE
            train_state, time_state, env_state, last_obs, rng = runner_state
            _, last_val = network.apply(train_state.params, last_obs)

            def _calculate_gae(traj_batch, last_val):
                def _get_advantages(gae_and_next_value, transition):
                    gae, next_value = gae_and_next_value
                    done, value, reward = (
                        transition.done,
                        transition.value,
                        transition.reward,
                    )
                    delta = reward + config["GAMMA"] * next_value * (1 - done) - value
                    gae = (
                        delta
                        + config["GAMMA"] * config["GAE_LAMBDA"] * (1 - done) * gae
                    )
                    return (gae, value), gae

                _, advantages = jax.lax.scan(
                    _get_advantages,
                    (jnp.zeros_like(last_val), last_val),
                    traj_batch,
                    reverse=True,
                    unroll=16,
                )
                return advantages, advantages + traj_batch.value

            advantages, targets = _calculate_gae(traj_batch, last_val)

            # UPDATE NETWORK
            def _update_epoch(update_state, unused):
                def _update_minbatch(train_state, batch_info):
                    traj_batch, advantages, targets = batch_info

                    def _loss_fn(params, traj_batch, gae, targets):
                        # RERUN NETWORK
                        pi, value = network.apply(params, traj_batch.obs)
                        log_prob = pi.log_prob(traj_batch.action)

                        # CALCULATE VALUE LOSS
                        value_pred_clipped = traj_batch.value + (
                            value - traj_batch.value
                        ).clip(-config["CLIP_EPS"], config["CLIP_EPS"])
                        value_losses = jnp.square(value - targets)
                        value_losses_clipped = jnp.square(value_pred_clipped - targets)
                        value_loss = (
                            0.5 * jnp.maximum(value_losses, value_losses_clipped).mean()
                        )

                        # CALCULATE ACTOR LOSS
                        ratio = jnp.exp(log_prob - traj_batch.log_prob)
                        gae = (gae - gae.mean()) / (gae.std() + 1e-8)
                        loss_actor1 = ratio * gae
                        loss_actor2 = (
                            jnp.clip(
                                ratio,
                                1.0 - config["CLIP_EPS"],
                                1.0 + config["CLIP_EPS"],
                            )
                            * gae
                        )
                        loss_actor = -jnp.minimum(loss_actor1, loss_actor2)
                        loss_actor = loss_actor.mean()
                        entropy = pi.entropy().mean()

                        total_loss = (
                            loss_actor
                            + config["VF_COEF"] * value_loss
                            - config["ENT_COEF"] * entropy
                        )
                        return total_loss, (value_loss, loss_actor, entropy)

                    grad_fn = jax.value_and_grad(_loss_fn, has_aux=True)
                    total_loss, grads = grad_fn(
                        train_state.params, traj_batch, advantages, targets
                    )
                    train_state = train_state.apply_gradients(grads=grads)
                    return train_state, total_loss

                train_state, traj_batch, advantages, targets, rng = update_state
                rng, _rng = jax.random.split(rng)
                # Batching and Shuffling
                batch_size = config["MINIBATCH_SIZE"] * config["NUM_MINIBATCHES"]
                assert (
                    batch_size == config["NUM_STEPS"] * config["NUM_ENVS"]
                ), "batch size must be equal to number of steps * number of envs"
                permutation = jax.random.permutation(_rng, batch_size)
                batch = (traj_batch, advantages, targets)
                batch = jax.tree_util.tree_map(
                    lambda x: x.reshape((batch_size,) + x.shape[2:]), batch
                )
                shuffled_batch = jax.tree_util.tree_map(
                    lambda x: jnp.take(x, permutation, axis=0), batch
                )
                # Mini-batch Updates
                minibatches = jax.tree_util.tree_map(
                    lambda x: jnp.reshape(
                        x, [config["NUM_MINIBATCHES"], -1] + list(x.shape[1:])
                    ),
                    shuffled_batch,
                )
                train_state, total_loss = jax.lax.scan(
                    _update_minbatch, train_state, minibatches
                )
                update_state = (train_state, traj_batch, advantages, targets, rng)
                return update_state, total_loss

            # Updating Training State and Metrics:
            update_state = (train_state, traj_batch, advantages, targets, rng)
            update_state, loss_info = jax.lax.scan(
                _update_epoch, update_state, None, config["UPDATE_EPOCHS"]
            )
            train_state = update_state[0]
            metric = traj_batch.info
            rng = update_state[-1]
            time_state["timesteps"] = time_state["timesteps"] + 512
            metric["time"] = time_state["timesteps"]
            metric["loss"] = loss_info

            # Debugging mode
            if config.get("DEBUG"):

                def callback(info):
                    return_values = info["returned_episode_returns"][
                        info["returned_episode"]
                    ]
                    timesteps = (
                        info["timestep"][info["returned_episode"]] * config["NUM_ENVS"]
                    )
                    for t in range(len(timesteps)):
                        print(
                            f"global step={timesteps[t]}, episodic return={return_values[t]}"
                        )
                        
                    data_log = {
                        "losses/value_loss": info["loss"][1][0].mean().item(),
                        "losses/policy_loss": info["loss"][1][1].mean().item(),
                        "losses/entropy": info["loss"][1][2].mean().item(),
                        "losses/total_loss": info["loss"][0].mean().item(),
                    }
                    if return_values.size > 0:
                        data_log["misc/episodic_return"] = return_values.mean().item()
                    wandb.log(data_log, step=info["time"])

                jax.debug.callback(callback, metric)

            runner_state = (train_state, time_state, env_state, last_obs, rng)
            return runner_state, metric

        rng, _rng = jax.random.split(rng)
        time_state = {"timesteps": jnp.array(0)}
        runner_state = (train_state, time_state, env_state, obsv, _rng)
        runner_state, metric = jax.lax.scan(
            _update_step, runner_state, None, config["NUM_UPDATES"]
        )
        return {"runner_state": runner_state, "metrics": metric}

    return train


if __name__ == "__main__":
    config = {
        "LR": 2.5e-4,
        "NUM_ENVS": 4,
        "NUM_STEPS": 128,
        "TOTAL_TIMESTEPS": 100000,
        "UPDATE_EPOCHS": 4,
        "NUM_MINIBATCHES": 4,
        "GAMMA": 0.99,
        "GAE_LAMBDA": 0.95,
        "CLIP_EPS": 0.2,
        "ENT_COEF": 0.01,
        "VF_COEF": 0.5,
        "MAX_GRAD_NORM": 0.5,
        "ACTIVATION": "tanh",
        "ENV_NAME": "CartPole-v1",
        "ANNEAL_LR": True,
        "DEBUG": True,
    }
    run_name = f"test"
    wandb_id = wandb.util.generate_id()
    run_id = f"{run_name}_{wandb_id}"
    
    wandb.init(
        id=run_id,
        project="test5",
        name=run_name,
        mode="online",
    )
    
    rng = jax.random.PRNGKey(30)
    train_jit = jax.jit(make_train(config))
    out = train_jit(rng)