Skip to main content

Transformer Metacontroller

Project description

metacontroller

Implementation of the MetaController proposed in Emergent temporal abstractions in autoregressive models enable hierarchical reinforcement learning, from the Paradigms of Intelligence team at Google

Install

$ pip install metacontroller-pytorch

Appreciation

  • Pranoy for submitting a pull request for fixing the previous latent action not being included in the inputs to the switching unit

  • Diego Calanzone for proposing testing on BabyAI gridworld task, and submitting the pull request for behavior cloning and discovery phase training for it!

  • Andrew Song for ongoing implementation of the PinPad environment!

  • Diego Calanzone for his experimental acumen, bringing the project to an initial working state for the BabyAI environment!

  • Andrew Song for implementing linear probing and fixing an issue with the action space

  • Andrew Song for identifying a critical issue with past action embed handling and detaching gradients of target states

  • Diego Calanzone for identifying inconsistencies in the MetaController

Usage

import torch
from metacontroller import Transformer, MetaController

# 1. initialize model

model = Transformer(
    dim = 512,
    action_embed_readout = dict(num_discrete = 4),
    state_embed_readout = dict(num_continuous = 384),
    lower_body = dict(depth = 2),
    upper_body = dict(depth = 2)
)

state = torch.randn(2, 128, 384)
actions = torch.randint(0, 4, (2, 128))

# 2. behavioral cloning (BC)

state_loss, action_loss = model(state, actions)
(state_loss + action_loss).backward()

# 3. discovery phase

meta_controller = MetaController(
    dim_model = 512,
    dim_meta_controller = 256,
    dim_latent = 128
)

state_pred_loss, action_recon_loss, kl_loss, aux_ratio_loss = model(
    state,
    actions,
    meta_controller = meta_controller,
    discovery_phase = True
)

# they did not use state pred loss in the paper (weight set to 0, but available)
# the ratio loss from h-net paper is also available, but optional (set ratio_loss_weight > 0)

(action_recon_loss + kl_loss * 0.1).backward()

# 4. internal rl phase (GRPO)

# ... collect trajectories ...

logits, cache = model(
    one_state,
    past_action_id,
    meta_controller = meta_controller,
    return_cache = True
)

meta_output = cache.prev_hiddens.meta_controller
old_log_probs = meta_controller.log_prob(meta_output.action_dist, meta_output.actions)

# ... calculate advantages ...

# for GRPO, the inputs to policy loss should be of shape (batch, seq, dim_latent)
# where dim_latent is the dimension of the latent action space

loss = meta_controller.policy_loss(
    group_states,
    group_old_log_probs,
    group_latent_actions,
    group_advantages,
    group_switch_betas
)

loss.backward()

Or using evolutionary strategies for the last portion

# 5. evolve (ES over GRPO)

model.meta_controller = meta_controller

def environment_callable(model):
    # return a fitness score
    return 1.0

model.evolve(
    num_generations = 10,
    environment = environment_callable
)

Citations

@misc{kobayashi2025emergenttemporalabstractionsautoregressive,
    title   = {Emergent temporal abstractions in autoregressive models enable hierarchical reinforcement learning}, 
    author  = {Seijin Kobayashi and Yanick Schimpf and Maximilian Schlegel and Angelika Steger and Maciej Wolczyk and Johannes von Oswald and Nino Scherrer and Kaitlin Maile and Guillaume Lajoie and Blake A. Richards and Rif A. Saurous and James Manyika and Blaise Agüera y Arcas and Alexander Meulemans and João Sacramento},
    year    = {2025},
    eprint  = {2512.20605},
    archivePrefix = {arXiv},
    primaryClass = {cs.LG},
    url     = {https://arxiv.org/abs/2512.20605}, 
}
@article{Wagenmaker2025SteeringYD,
    title   = {Steering Your Diffusion Policy with Latent Space Reinforcement Learning},
    author  = {Andrew Wagenmaker and Mitsuhiko Nakamoto and Yunchu Zhang and Seohong Park and Waleed Yagoub and Anusha Nagabandi and Abhishek Gupta and Sergey Levine},
    journal = {ArXiv},
    year    = {2025},
    volume  = {abs/2506.15799},
    url     = {https://api.semanticscholar.org/CorpusID:279464702}
}
@misc{hwang2025dynamicchunkingendtoendhierarchical,
    title   = {Dynamic Chunking for End-to-End Hierarchical Sequence Modeling},
    author  = {Sukjun Hwang and Brandon Wang and Albert Gu},
    year    = {2025},
    eprint  = {2507.07955},
    archivePrefix = {arXiv},
    primaryClass = {cs.LG},
    url     = {https://arxiv.org/abs/2507.07955},
}
@misc{fleuret2025freetransformer,
    title     = {The Free Transformer}, 
    author    = {François Fleuret},
    year      = {2025},
    eprint    = {2510.17558},
    archivePrefix = {arXiv},
    primaryClass = {cs.LG},
    url       = {https://arxiv.org/abs/2510.17558}, 
}

Life can only be understood backwards; but it must be lived forwards - Søren Kierkegaard

Project details


Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

metacontroller_pytorch-0.2.1.tar.gz (36.9 MB view details)

Uploaded Source

Built Distribution

If you're not sure about the file name format, learn more about wheel file names.

metacontroller_pytorch-0.2.1-py3-none-any.whl (19.0 kB view details)

Uploaded Python 3

File details

Details for the file metacontroller_pytorch-0.2.1.tar.gz.

File metadata

  • Download URL: metacontroller_pytorch-0.2.1.tar.gz
  • Upload date:
  • Size: 36.9 MB
  • Tags: Source
  • Uploaded using Trusted Publishing? No
  • Uploaded via: twine/6.2.0 CPython/3.9.25

File hashes

Hashes for metacontroller_pytorch-0.2.1.tar.gz
Algorithm Hash digest
SHA256 e91d90ff0a7535e0029aa4f5c25447f822b8969811aa85d732b2fbe6c44bae94
MD5 928d683e34eef33e1b8bb5a38d35370d
BLAKE2b-256 e43c07072633b8a574a0a4d6db72fbe4e3f2e784516f931710ca7e7bad30fa6a

See more details on using hashes here.

File details

Details for the file metacontroller_pytorch-0.2.1-py3-none-any.whl.

File metadata

File hashes

Hashes for metacontroller_pytorch-0.2.1-py3-none-any.whl
Algorithm Hash digest
SHA256 5285d51dcb280973fcbdd0d7ffe934fb15d9347cb017bc4013a4ef1b2ad5b208
MD5 33c3e2b8a3122c5e25dda090de69611c
BLAKE2b-256 d2d3d24c5f189814bef263dc48fd7cc7e895f915b640f552f6b7c9aaa5f7cf8e

See more details on using hashes here.

Supported by

AWS Cloud computing and Security Sponsor Datadog Monitoring Depot Continuous Integration Fastly CDN Google Download Analytics Pingdom Monitoring Sentry Error logging StatusPage Status page