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# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
from typing import Sequence
from torch.utils.data import BatchSampler, Sampler
from mmdet.datasets.samplers.track_img_sampler import TrackImgSampler
from mmdet.registry import DATA_SAMPLERS
# TODO: maybe replace with a data_loader wrapper
@DATA_SAMPLERS.register_module()
class AspectRatioBatchSampler(BatchSampler):
"""A sampler wrapper for grouping images with similar aspect ratio (< 1 or.
>= 1) into a same batch.
Args:
sampler (Sampler): Base sampler.
batch_size (int): Size of mini-batch.
drop_last (bool): If ``True``, the sampler will drop the last batch if
its size would be less than ``batch_size``.
"""
def __init__(self,
sampler: Sampler,
batch_size: int,
drop_last: bool = False) -> None:
if not isinstance(sampler, Sampler):
raise TypeError('sampler should be an instance of ``Sampler``, '
f'but got {sampler}')
if not isinstance(batch_size, int) or batch_size <= 0:
raise ValueError('batch_size should be a positive integer value, '
f'but got batch_size={batch_size}')
self.sampler = sampler
self.batch_size = batch_size
self.drop_last = drop_last
# two groups for w < h and w >= h
self._aspect_ratio_buckets = [[] for _ in range(2)]
def __iter__(self) -> Sequence[int]:
for idx in self.sampler:
data_info = self.sampler.dataset.get_data_info(idx)
width, height = data_info['width'], data_info['height']
bucket_id = 0 if width < height else 1
bucket = self._aspect_ratio_buckets[bucket_id]
bucket.append(idx)
# yield a batch of indices in the same aspect ratio group
if len(bucket) == self.batch_size:
yield bucket[:]
del bucket[:]
# yield the rest data and reset the bucket
left_data = self._aspect_ratio_buckets[0] + self._aspect_ratio_buckets[
1]
self._aspect_ratio_buckets = [[] for _ in range(2)]
while len(left_data) > 0:
if len(left_data) <= self.batch_size:
if not self.drop_last:
yield left_data[:]
left_data = []
else:
yield left_data[:self.batch_size]
left_data = left_data[self.batch_size:]
def __len__(self) -> int:
if self.drop_last:
return len(self.sampler) // self.batch_size
else:
return (len(self.sampler) + self.batch_size - 1) // self.batch_size
@DATA_SAMPLERS.register_module()
class TrackAspectRatioBatchSampler(AspectRatioBatchSampler):
"""A sampler wrapper for grouping images with similar aspect ratio (< 1 or.
>= 1) into a same batch.
Args:
sampler (Sampler): Base sampler.
batch_size (int): Size of mini-batch.
drop_last (bool): If ``True``, the sampler will drop the last batch if
its size would be less than ``batch_size``.
"""
def __iter__(self) -> Sequence[int]:
for idx in self.sampler:
# hard code to solve TrackImgSampler
if isinstance(self.sampler, TrackImgSampler):
video_idx, _ = idx
else:
video_idx = idx
# video_idx
data_info = self.sampler.dataset.get_data_info(video_idx)
# data_info {video_id, images, video_length}
img_data_info = data_info['images'][0]
width, height = img_data_info['width'], img_data_info['height']
bucket_id = 0 if width < height else 1
bucket = self._aspect_ratio_buckets[bucket_id]
bucket.append(idx)
# yield a batch of indices in the same aspect ratio group
if len(bucket) == self.batch_size:
yield bucket[:]
del bucket[:]
# yield the rest data and reset the bucket
left_data = self._aspect_ratio_buckets[0] + self._aspect_ratio_buckets[
1]
self._aspect_ratio_buckets = [[] for _ in range(2)]
while len(left_data) > 0:
if len(left_data) <= self.batch_size:
if not self.drop_last:
yield left_data[:]
left_data = []
else:
yield left_data[:self.batch_size]
left_data = left_data[self.batch_size:]
@DATA_SAMPLERS.register_module()
class MultiDataAspectRatioBatchSampler(BatchSampler):
"""A sampler wrapper for grouping images with similar aspect ratio (< 1 or.
>= 1) into a same batch for multi-source datasets.
Args:
sampler (Sampler): Base sampler.
batch_size (Sequence(int)): Size of mini-batch for multi-source
datasets.
num_datasets(int): Number of multi-source datasets.
drop_last (bool): If ``True``, the sampler will drop the last batch if
its size would be less than ``batch_size``.
"""
def __init__(self,
sampler: Sampler,
batch_size: Sequence[int],
num_datasets: int,
drop_last: bool = True) -> None:
if not isinstance(sampler, Sampler):
raise TypeError('sampler should be an instance of ``Sampler``, '
f'but got {sampler}')
self.sampler = sampler
self.batch_size = batch_size
self.num_datasets = num_datasets
self.drop_last = drop_last
# two groups for w < h and w >= h for each dataset --> 2 * num_datasets
self._buckets = [[] for _ in range(2 * self.num_datasets)]
def __iter__(self) -> Sequence[int]:
for idx in self.sampler:
data_info = self.sampler.dataset.get_data_info(idx)
width, height = data_info['width'], data_info['height']
dataset_source_idx = self.sampler.dataset.get_dataset_source(idx)
aspect_ratio_bucket_id = 0 if width < height else 1
bucket_id = dataset_source_idx * 2 + aspect_ratio_bucket_id
bucket = self._buckets[bucket_id]
bucket.append(idx)
# yield a batch of indices in the same aspect ratio group
if len(bucket) == self.batch_size[dataset_source_idx]:
yield bucket[:]
del bucket[:]
# yield the rest data and reset the bucket
for i in range(self.num_datasets):
left_data = self._buckets[i * 2 + 0] + self._buckets[i * 2 + 1]
while len(left_data) > 0:
if len(left_data) <= self.batch_size[i]:
if not self.drop_last:
yield left_data[:]
left_data = []
else:
yield left_data[:self.batch_size[i]]
left_data = left_data[self.batch_size[i]:]
self._buckets = [[] for _ in range(2 * self.num_datasets)]
def __len__(self) -> int:
sizes = [0 for _ in range(self.num_datasets)]
for idx in self.sampler:
dataset_source_idx = self.sampler.dataset.get_dataset_source(idx)
sizes[dataset_source_idx] += 1
if self.drop_last:
lens = 0
for i in range(self.num_datasets):
lens += sizes[i] // self.batch_size[i]
return lens
else:
lens = 0
for i in range(self.num_datasets):
lens += (sizes[i] + self.batch_size[i] -
1) // self.batch_size[i]
return lens