lerobot/lerobot/common/datasets/sampler.py

62 lines
2.3 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.
from typing import Iterator, Union
import torch
class EpisodeAwareSampler:
def __init__(
self,
episode_data_index: dict,
episode_indices_to_use: Union[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:
episode_data_index: Dictionary with keys 'from' and 'to' containing the start and end indices of each episode.
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.
"""
indices = []
for episode_idx, (start_index, end_index) in enumerate(
zip(episode_data_index["from"], episode_data_index["to"], strict=True)
):
if episode_indices_to_use is None or episode_idx in episode_indices_to_use:
indices.extend(
range(start_index.item() + drop_n_first_frames, end_index.item() - drop_n_last_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)