Files
lerobot/tests/policies/fastwam/test_fastwam_policy.py
T
Maxime Ellerbach 141c353206 feat(policies): Add FastWAM Policy (#3834)
* Add FastWAM policy

* Add FastWAM policy review updates

* big refactor to use models from diffusers and transformers

* changing reproducable results

* preparing for training adding some temporary debug code aswell to visualize model output

* re-parenting of some layers to enable proper zero-3 FSDP

* linting

* small fix for the preprocessor and padded images

* removing some preprocessors

* removing temporary debug code

* cleaning up

* updating uv lock after rebasing

* adding lazy imports

* linting

* fixing stale assertion

* make tokenizer/text-encoder model ids configurable + some nits

* moving and renaming files to have a cleaner file tree

* removed asserts from the model, added guard instead and completely removed useless asserts

* cleaning up imports

* removing is_main_process and custom logging logic

* removing unused / stale attention path, removing some of the stale forwards within wan/models

---------

Co-authored-by: ZibinDong <zibindong@outlook.com>
Co-authored-by: Steven Palma <imstevenpmwork@ieee.org>
2026-07-01 14:35:57 +02:00

392 lines
15 KiB
Python

#!/usr/bin/env python
# Copyright 2024 The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import json
import pytest
import torch
from safetensors import safe_open
from torch import nn
pytest.importorskip("transformers", reason="fastwam requires the `fastwam` extra (transformers)")
pytest.importorskip("diffusers", reason="fastwam requires the `fastwam` extra (diffusers)")
from lerobot.configs import FeatureType, PolicyFeature, PreTrainedConfig
from lerobot.policies import FastWAMConfig, get_policy_class, make_policy_config, make_pre_post_processors
from lerobot.policies.fastwam.modeling_fastwam import FastWAMPolicy
from lerobot.policies.fastwam.processor_fastwam import FastWAMActionToggleProcessorStep
from lerobot.utils.constants import ACTION, OBS_STATE
class FakeFastWAMCore(nn.Module):
def __init__(self):
super().__init__()
self.dit = nn.Linear(2, 2)
def training_loss(self, sample):
assert sample["video"].ndim == 5
assert sample["context"].ndim == 3
return sample[ACTION].sum() * 0.0 + torch.tensor(1.0), {"loss_action": 1.0}
def infer_action(self, **kwargs):
return {"action": torch.ones(1, kwargs["action_horizon"], 3)}
def test_fastwam_is_registered_and_publicly_exported():
cfg = make_policy_config(
"fastwam",
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
base_model_id=None,
)
assert isinstance(cfg, FastWAMConfig)
assert cfg.type == "fastwam"
assert get_policy_class("fastwam") is FastWAMPolicy
def test_config_validates_features_model_ids_and_saved_auto_route(tmp_path):
cfg = FastWAMConfig()
cfg.save_pretrained(tmp_path)
saved = json.loads((tmp_path / "config.json").read_text())
assert saved["pretrained_path"] is None
assert cfg.image_features["observation.images.image"].type == FeatureType.VISUAL
assert cfg.action_feature.shape == (7,)
assert cfg.robot_state_feature.shape == (8,)
with pytest.raises(ValueError, match="image feature"):
FastWAMConfig(input_features={OBS_STATE: PolicyFeature(type=FeatureType.STATE, shape=(8,))})
assert FastWAMConfig(tokenizer_model_id="somebody/other-tokenizer").tokenizer_model_id == (
"somebody/other-tokenizer"
)
def test_preprocessor_passes_images_through_and_postprocessor_toggles_actions(tmp_path):
cfg = FastWAMConfig(
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
image_size=(2, 2),
device="cpu",
toggle_action_dimensions=[-1],
input_features={
"observation.images.image": PolicyFeature(type=FeatureType.VISUAL, shape=(3, 2, 2)),
OBS_STATE: PolicyFeature(type=FeatureType.STATE, shape=(2,)),
},
output_features={ACTION: PolicyFeature(type=FeatureType.ACTION, shape=(3,))},
base_model_id=None,
)
dataset_stats = {
"observation.images.image": {
"mean": torch.full((3, 1, 1), 0.2),
"std": torch.full((3, 1, 1), 0.1),
},
OBS_STATE: {
"mean": torch.tensor([1.0, 3.0]),
"std": torch.tensor([2.0, 4.0]),
},
ACTION: {
"mean": torch.zeros(3),
"std": torch.ones(3),
},
}
preprocessor, postprocessor = make_pre_post_processors(cfg, dataset_stats=dataset_stats)
processed = preprocessor(
{
"observation.images.image": torch.tensor(
[
[[0.0, 0.5], [1.0, 0.5]],
[[0.0, 0.5], [1.0, 0.5]],
[[0.0, 0.5], [1.0, 0.5]],
]
),
OBS_STATE: torch.tensor([3.0, 7.0]),
}
)
preprocessor.save_pretrained(tmp_path, config_filename="policy_preprocessor.json")
postprocessor.save_pretrained(tmp_path, config_filename="policy_postprocessor.json")
_, loaded_postprocessor = make_pre_post_processors(cfg, pretrained_path=str(tmp_path))
# VISUAL normalization is IDENTITY
expected_image = torch.tensor(
[[[[0.0, 0.5], [1.0, 0.5]], [[0.0, 0.5], [1.0, 0.5]], [[0.0, 0.5], [1.0, 0.5]]]]
)
assert preprocessor.name == "policy_preprocessor"
assert postprocessor.name == "policy_postprocessor"
assert torch.allclose(processed["observation.images.image"], expected_image)
assert torch.allclose(processed[OBS_STATE], torch.tensor([[1.0, 1.0]]))
assert torch.equal(dataset_stats["observation.images.image"]["mean"], torch.full((3, 1, 1), 0.2))
assert any(isinstance(step, FastWAMActionToggleProcessorStep) for step in loaded_postprocessor.steps)
assert torch.equal(
loaded_postprocessor(torch.tensor([[0.25, 0.5, 1.0]])), torch.tensor([[0.25, 0.5, -1.0]])
)
def test_policy_forward_and_predict_action_adapt_lerobot_batches(monkeypatch):
captured = []
class CapturingCore(FakeFastWAMCore):
def infer_action(self, **kwargs):
captured.append(
{
"image_shape": tuple(kwargs["input_image"].shape),
"proprio_shape": tuple(kwargs["proprio"].shape),
"prompt": kwargs["prompt"],
}
)
return {"action": torch.full((1, kwargs["action_horizon"], 3), float(len(captured)))}
monkeypatch.setattr(FastWAMPolicy, "_build_core_model", lambda self, config: CapturingCore())
cfg = FastWAMConfig(
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
image_size=(16, 16),
input_features={
"observation.images.image": PolicyFeature(type=FeatureType.VISUAL, shape=(3, 16, 16)),
OBS_STATE: PolicyFeature(type=FeatureType.STATE, shape=(2,)),
},
output_features={ACTION: PolicyFeature(type=FeatureType.ACTION, shape=(3,))},
base_model_id=None,
)
policy = FastWAMPolicy(cfg)
loss, metrics = policy.forward(
{
"observation.images.image": torch.zeros(1, 3, 16, 16),
OBS_STATE: torch.zeros(1, 2),
ACTION: torch.zeros(1, 4, 3),
"context": torch.zeros(1, 5, 4096),
"context_mask": torch.ones(1, 5, dtype=torch.bool),
}
)
action = policy.predict_action_chunk(
{
"observation.images.image": torch.stack(
[
torch.zeros(3, 16, 16),
torch.ones(3, 16, 16),
]
),
OBS_STATE: torch.tensor([[0.0, 1.0], [2.0, 3.0]]),
"task": ["task 0", "task 1"],
}
)
assert loss.item() == 1.0
assert metrics["loss_action"] == 1.0
assert action.shape == (2, 4, 3)
assert action[:, 0, 0].tolist() == [1.0, 2.0]
assert [item["image_shape"] for item in captured] == [(1, 3, 16, 16), (1, 3, 16, 16)]
assert [item["proprio_shape"] for item in captured] == [(1, 2), (1, 2)]
assert [item["prompt"] for item in captured] == [
cfg.prompt_template.format(task="task 0"),
cfg.prompt_template.format(task="task 1"),
]
class CoreWithFrozenComponents(FakeFastWAMCore):
"""Fake core mirroring the real one: frozen VAE / text encoder held as
*unregistered* attributes (via `object.__setattr__`) so they are excluded from
`state_dict()` and the saved checkpoint, but still moved by the `_apply` override."""
def __init__(self):
super().__init__()
object.__setattr__(self, "vae", nn.Linear(2, 2))
object.__setattr__(self, "text_encoder", nn.Linear(2, 2))
self.vae.requires_grad_(False)
self.text_encoder.requires_grad_(False)
def _apply(self, fn, *args, **kwargs):
super()._apply(fn, *args, **kwargs)
self.vae._apply(fn)
self.text_encoder._apply(fn)
return self
def test_from_pretrained_uses_base_loader_and_skips_wan_backbone(monkeypatch, tmp_path):
cfg = FastWAMConfig(
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
base_model_id=None,
)
def build_core(self, config):
core = CoreWithFrozenComponents()
with torch.no_grad():
core.dit.weight.fill_(0.5)
return core
monkeypatch.setattr(FastWAMPolicy, "_build_core_model", build_core)
reference = FastWAMPolicy(cfg)
with torch.no_grad():
reference.model.dit.weight.fill_(1.25) # a distinctive, trained-looking weight
reference.save_pretrained(tmp_path)
# Building from Wan2.2 must never happen on a checkpoint load.
def fail_if_wan_pretrained_is_loaded(*args, **kwargs):
raise AssertionError("from_pretrained must not initialize or download the Wan2.2 backbone")
monkeypatch.setattr(
"lerobot.policies.fastwam.wan.modular.FastWAM.from_wan22_pretrained",
fail_if_wan_pretrained_is_loaded,
)
policy = FastWAMPolicy.from_pretrained(tmp_path)
assert isinstance(policy.model, CoreWithFrozenComponents)
# The bundled checkpoint weights overwrote the freshly built (0.5) DiT weights.
assert torch.allclose(policy.model.dit.weight, torch.full_like(policy.model.dit.weight, 1.25))
def test_save_pretrained_excludes_frozen_components(monkeypatch, tmp_path):
cfg = FastWAMConfig(
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
base_model_id=None,
)
monkeypatch.setattr(FastWAMPolicy, "_build_core_model", lambda self, config: CoreWithFrozenComponents())
policy = FastWAMPolicy(cfg)
save_dir = tmp_path / "saved"
policy.save_pretrained(save_dir)
assert (save_dir / "model.safetensors").is_file()
# No Wan sidecar files either: the frozen backbone comes from the diffusers repo.
assert not (save_dir / "Wan2.2_VAE.safetensors").exists()
assert not (save_dir / "google").exists()
with safe_open(save_dir / "model.safetensors", framework="pt") as f:
keys = set(f.keys())
# Lean checkpoint: only the trainable DiT is saved; the frozen VAE / UMT5 text
# encoder are excluded (loaded from the diffusers/transformers repos at init).
assert any(key.startswith("model.dit.") for key in keys)
assert not any(key.startswith("model.vae.") for key in keys)
assert not any(key.startswith("model.text_encoder.") for key in keys)
def test_frozen_components_excluded_from_params_but_follow_device_moves(monkeypatch):
cfg = FastWAMConfig(
action_dim=3,
proprio_dim=2,
action_horizon=4,
n_action_steps=2,
num_video_frames=5,
action_video_freq_ratio=1,
base_model_id=None,
)
monkeypatch.setattr(FastWAMPolicy, "_build_core_model", lambda self, config: CoreWithFrozenComponents())
policy = FastWAMPolicy(cfg)
# Unregistered: excluded from state_dict and from the optimizer's parameter set.
sd = policy.state_dict()
assert not any(k.startswith("model.vae.") or k.startswith("model.text_encoder.") for k in sd)
param_names = [n for n, _ in policy.named_parameters()]
assert not any("vae" in n or "text_encoder" in n for n in param_names)
# ...but the `_apply` override still carries them through `.to()` (dtype stands in
# for device on a CPU box), so they never strand off the rest of the model.
policy.to(torch.float64)
assert policy.model.dit.weight.dtype == torch.float64 # registered
assert policy.model.vae.weight.dtype == torch.float64 # unregistered, moved via _apply
assert policy.model.text_encoder.weight.dtype == torch.float64
def test_pretrained_config_round_trips_fastwam_features(tmp_path):
cfg = FastWAMConfig(action_dim=7, proprio_dim=8, image_size=(224, 448), base_model_id=None)
cfg.save_pretrained(tmp_path)
loaded = PreTrainedConfig.from_pretrained(tmp_path)
assert loaded.type == "fastwam"
assert loaded.image_features["observation.images.image"].type == FeatureType.VISUAL
assert loaded.action_feature.shape == (7,)
assert loaded.robot_state_feature.shape == (8,)
def test_vae_adapter_empty_build_encode_decode_shapes():
"""Offline glue check of the diffusers-backed VAE adapter (random weights).
Validates the encode/decode contract — 48 latent channels, 16x spatial / 4x
temporal compression, list-or-batch input, scaling round-trip — without any
weight download. (Numerical fidelity vs the original Wan VAE is a separate,
GPU + real-weights verification step.)
"""
pytest.importorskip("diffusers")
from diffusers import AutoencoderKLWan
from lerobot.policies.fastwam.wan import WanVideoVAE38
# Production always loads a real pretrained VAE from the diffusers repo; here we
# build the same architecture with random weights and dummy standardization stats
# to exercise the adapter's shape/scaling contract offline (fidelity is checked
# separately, with real weights, on GPU).
arch = {
"base_dim": 160,
"decoder_base_dim": 256,
"z_dim": 48,
"dim_mult": [1, 2, 4, 4],
"num_res_blocks": 2,
"attn_scales": [],
"temporal_downsample": [False, True, True],
"dropout": 0.0,
"is_residual": True,
"in_channels": 12,
"out_channels": 12,
"patch_size": 2,
"scale_factor_spatial": 16,
"scale_factor_temporal": 4,
"clip_output": False,
"latents_mean": [0.0] * 48,
"latents_std": [1.0] * 48,
}
raw = AutoencoderKLWan.from_config(arch)
vae = WanVideoVAE38(dtype=torch.float32, device="cpu", pretrained=raw)
assert vae.z_dim == 48
assert vae.upsampling_factor == 16
assert vae.temporal_downsample_factor == 4
video = torch.rand(1, 3, 5, 32, 32) * 2 - 1 # [B,C,T,H,W] in [-1,1]
latents = vae.encode(video)
assert latents.shape == (1, 48, 2, 2, 2) # T'=(5-1)//4+1, H'=W'=32//16
decoded = vae.decode(latents)
assert decoded.shape[0] == 1 and decoded.shape[1] == 3 and decoded.shape[-2:] == (32, 32)
assert decoded.min() >= -1.0 and decoded.max() <= 1.0
# list input is accepted and equals the batched path
assert torch.equal(vae.encode([video[0]]), latents)