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lerobot-clone/lerobot/common/policies/normalize.py
2025-06-05 14:13:45 +02:00

231 lines
9.2 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 numpy as np
import torch
from torch import Tensor, nn
from lerobot.configs.types import FeatureType, NormalizationMode, PolicyFeature
def _no_stats_error_str(name: str) -> str:
return (
f"`{name}` is infinity. You should either initialize with `stats` as an argument, or use a "
"pretrained model."
)
def _initialize_stats_buffers(
module: nn.Module,
features: dict[str, PolicyFeature],
norm_map: dict[str, NormalizationMode],
stats: dict[str, dict[str, Tensor]] | None = None,
) -> None:
"""Register statistics buffers (mean/std or min/max) on the given *module*.
The logic matches the previous constructors of `NormalizeBuffer` and `UnnormalizeBuffer`,
but is factored out so it can be reused by both classes and stay in sync.
"""
for key, ft in features.items():
norm_mode = norm_map.get(ft.type, NormalizationMode.IDENTITY)
if norm_mode is NormalizationMode.IDENTITY:
continue
shape: tuple[int, ...] = tuple(ft.shape)
if ft.type is FeatureType.VISUAL:
# reduce spatial dimensions, keep channel dimension only
c, *_ = shape
shape = (c, 1, 1)
prefix = key.replace(".", "_")
if norm_mode is NormalizationMode.MEAN_STD:
mean = torch.full(shape, torch.inf, dtype=torch.float32)
std = torch.full(shape, torch.inf, dtype=torch.float32)
if stats and key in stats and "mean" in stats[key] and "std" in stats[key]:
mean_data = stats[key]["mean"]
std_data = stats[key]["std"]
if isinstance(mean_data, torch.Tensor):
# Note: The clone is needed to make sure that the logic in save_pretrained doesn't see duplicated
# tensors anywhere (for example, when we use the same stats for normalization and
# unnormalization). See the logic here
# https://github.com/huggingface/safetensors/blob/079781fd0dc455ba0fe851e2b4507c33d0c0d407/bindings/python/py_src/safetensors/torch.py#L97.
mean = mean_data.clone().to(dtype=torch.float32)
std = std_data.clone().to(dtype=torch.float32)
elif isinstance(mean_data, np.ndarray):
mean = torch.from_numpy(mean_data).to(dtype=torch.float32)
std = torch.from_numpy(std_data).to(dtype=torch.float32)
else:
raise ValueError(f"Unsupported stats type for key '{key}' (expected ndarray or Tensor).")
module.register_buffer(f"{prefix}_mean", mean)
module.register_buffer(f"{prefix}_std", std)
continue
if norm_mode is NormalizationMode.MIN_MAX:
min_val = torch.full(shape, torch.inf, dtype=torch.float32)
max_val = torch.full(shape, torch.inf, dtype=torch.float32)
if stats and key in stats and "min" in stats[key] and "max" in stats[key]:
min_data = stats[key]["min"]
max_data = stats[key]["max"]
if isinstance(min_data, torch.Tensor):
min_val = min_data.clone().to(dtype=torch.float32)
max_val = max_data.clone().to(dtype=torch.float32)
elif isinstance(min_data, np.ndarray):
min_val = torch.from_numpy(min_data).to(dtype=torch.float32)
max_val = torch.from_numpy(max_data).to(dtype=torch.float32)
else:
raise ValueError(f"Unsupported stats type for key '{key}' (expected ndarray or Tensor).")
module.register_buffer(f"{prefix}_min", min_val)
module.register_buffer(f"{prefix}_max", max_val)
continue
raise ValueError(norm_mode)
class Normalize(nn.Module):
"""Normalizes data (e.g. "observation.image") for more stable and faster convergence during training."""
def __init__(
self,
features: dict[str, PolicyFeature],
norm_map: dict[str, NormalizationMode],
stats: dict[str, dict[str, Tensor]] | None = None,
):
super().__init__()
self.features = features
self.norm_map = norm_map
_initialize_stats_buffers(self, features, norm_map, stats)
def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
batch = dict(batch)
for key, ft in self.features.items():
if key not in batch:
continue
norm_mode = self.norm_map.get(ft.type, NormalizationMode.IDENTITY)
if norm_mode is NormalizationMode.IDENTITY:
continue
prefix = key.replace(".", "_")
if norm_mode is NormalizationMode.MEAN_STD:
mean = getattr(self, f"{prefix}_mean")
std = getattr(self, f"{prefix}_std")
assert not torch.isinf(mean).any(), _no_stats_error_str("mean")
assert not torch.isinf(std).any(), _no_stats_error_str("std")
batch[key] = (batch[key] - mean) / (std + 1e-8)
continue
if norm_mode is NormalizationMode.MIN_MAX:
min_val = getattr(self, f"{prefix}_min")
max_val = getattr(self, f"{prefix}_max")
assert not torch.isinf(min_val).any(), _no_stats_error_str("min")
assert not torch.isinf(max_val).any(), _no_stats_error_str("max")
batch[key] = (batch[key] - min_val) / (max_val - min_val + 1e-8)
batch[key] = batch[key] * 2 - 1
continue
raise ValueError(norm_mode)
return batch
class Unnormalize(nn.Module):
"""Inverse operation of `Normalize`. Uses registered buffers for statistics."""
def __init__(
self,
features: dict[str, PolicyFeature],
norm_map: dict[str, NormalizationMode],
stats: dict[str, dict[str, Tensor]] | None = None,
):
super().__init__()
self.features = features
self.norm_map = norm_map
_initialize_stats_buffers(self, features, norm_map, stats)
def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
# batch = dict(batch)
for key, ft in self.features.items():
if key not in batch:
continue
norm_mode = self.norm_map.get(ft.type, NormalizationMode.IDENTITY)
if norm_mode is NormalizationMode.IDENTITY:
continue
prefix = key.replace(".", "_")
if norm_mode is NormalizationMode.MEAN_STD:
mean = getattr(self, f"{prefix}_mean")
std = getattr(self, f"{prefix}_std")
assert not torch.isinf(mean).any(), _no_stats_error_str("mean")
assert not torch.isinf(std).any(), _no_stats_error_str("std")
batch[key] = batch[key] * std + mean
continue
if norm_mode is NormalizationMode.MIN_MAX:
min_val = getattr(self, f"{prefix}_min")
max_val = getattr(self, f"{prefix}_max")
assert not torch.isinf(min_val).any(), _no_stats_error_str("min")
assert not torch.isinf(max_val).any(), _no_stats_error_str("max")
batch[key] = (batch[key] + 1) / 2
batch[key] = batch[key] * (max_val - min_val) + min_val
continue
raise ValueError(norm_mode)
return batch
def convert_normalize_to_buffer_state_dict(state_dict: dict[str, torch.Tensor]) -> dict[str, torch.Tensor]:
"""
Convert state dict from Normalize/Unnormalize classes to NormalizeBuffer/UnnormalizeBuffer format.
Args:
state_dict: State dict from a model using Normalize/Unnormalize classes
Returns:
Converted state dict compatible with NormalizeBuffer/UnnormalizeBuffer classes
Example:
# Old format (Normalize): "buffer_observation_image.mean"
# New format (NormalizeBuffer): "observation_image_mean"
"""
converted_state_dict = {}
for key, value in state_dict.items():
# Check if this is a normalization buffer parameter
if key.startswith("buffer_") and ("." in key):
# Extract the prefix and stat type
# e.g. "buffer_observation_image.mean" -> "observation_image", "mean"
buffer_part = key[7:] # Remove "buffer_" prefix
prefix, stat_type = buffer_part.rsplit(".", 1)
# Convert to new format: "observation_image_mean"
new_key = f"{prefix}_{stat_type}"
converted_state_dict[new_key] = value
else:
# Keep non-normalization keys unchanged
converted_state_dict[key] = value
return converted_state_dict