Files
lerobot-clone/src/lerobot/datasets/sampler.py
2026-03-15 22:12:09 -07:00

87 lines
3.4 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 logging
from collections.abc import Iterator
import torch
logger = logging.getLogger(__name__)
class EpisodeAwareSampler:
def __init__(
self,
dataset_from_indices: list[int],
dataset_to_indices: list[int],
episode_indices_to_use: list | None = None,
drop_n_first_frames: int = 0,
drop_n_last_frames: int = 0,
shuffle: bool = False,
):
"""Sampler that optionally incorporates episode boundary information.
Args:
dataset_from_indices: List of indices containing the start of each episode in the dataset.
dataset_to_indices: List of indices containing the end of each episode in the dataset.
episode_indices_to_use: List of episode indices to use. If None, all episodes are used.
Assumes that episodes are indexed from 0 to N-1.
drop_n_first_frames: Number of frames to drop from the start of each episode.
drop_n_last_frames: Number of frames to drop from the end of each episode.
shuffle: Whether to shuffle the indices.
"""
if drop_n_first_frames < 0:
raise ValueError(f"drop_n_first_frames must be >= 0, got {drop_n_first_frames}")
if drop_n_last_frames < 0:
raise ValueError(f"drop_n_last_frames must be >= 0, got {drop_n_last_frames}")
indices = []
for episode_idx, (start_index, end_index) in enumerate(
zip(dataset_from_indices, dataset_to_indices, strict=True)
):
if episode_indices_to_use is None or episode_idx in episode_indices_to_use:
ep_length = end_index - start_index
if drop_n_first_frames + drop_n_last_frames >= ep_length:
logger.warning(
"Episode %d has %d frames but drop_n_first_frames=%d and "
"drop_n_last_frames=%d removes all frames. Skipping.",
episode_idx,
ep_length,
drop_n_first_frames,
drop_n_last_frames,
)
continue
indices.extend(range(start_index + drop_n_first_frames, end_index - drop_n_last_frames))
if not indices:
raise ValueError(
"No valid frames remain after applying drop_n_first_frames and drop_n_last_frames. "
"All episodes were either filtered out or had too few frames."
)
self.indices = indices
self.shuffle = shuffle
def __iter__(self) -> Iterator[int]:
if self.shuffle:
for i in torch.randperm(len(self.indices)):
yield self.indices[i]
else:
for i in self.indices:
yield i
def __len__(self) -> int:
return len(self.indices)