mmselfsup/openselfsup/datasets/loader/build_loader.py

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2020-06-16 00:05:18 +08:00
import platform
import random
from functools import partial
import numpy as np
from mmcv.parallel import collate
from mmcv.runner import get_dist_info
from torch.utils.data import DataLoader
#from .sampler import DistributedGroupSampler, DistributedSampler, GroupSampler
from .sampler import DistributedSampler, DistributedGivenIterationSampler
from torch.utils.data import RandomSampler
if platform.system() != 'Windows':
# https://github.com/pytorch/pytorch/issues/973
import resource
rlimit = resource.getrlimit(resource.RLIMIT_NOFILE)
resource.setrlimit(resource.RLIMIT_NOFILE, (4096, rlimit[1]))
def build_dataloader(dataset,
imgs_per_gpu,
workers_per_gpu,
num_gpus=1,
dist=True,
shuffle=True,
replace=False,
seed=None,
**kwargs):
"""Build PyTorch DataLoader.
In distributed training, each GPU/process has a dataloader.
In non-distributed training, there is only one dataloader for all GPUs.
Args:
dataset (Dataset): A PyTorch dataset.
imgs_per_gpu (int): Number of images on each GPU, i.e., batch size of
each GPU.
workers_per_gpu (int): How many subprocesses to use for data loading
for each GPU.
num_gpus (int): Number of GPUs. Only used in non-distributed training.
dist (bool): Distributed training/test or not. Default: True.
shuffle (bool): Whether to shuffle the data at every epoch.
Default: True.
replace (bool): Replace or not in random shuffle.
It works on when shuffle is True.
kwargs: any keyword argument to be used to initialize DataLoader
Returns:
DataLoader: A PyTorch dataloader.
"""
if dist:
rank, world_size = get_dist_info()
sampler = DistributedSampler(
dataset, world_size, rank, shuffle=shuffle, replace=replace)
batch_size = imgs_per_gpu
num_workers = workers_per_gpu
else:
if replace:
raise NotImplemented
sampler = RandomSampler(
dataset) if shuffle else None # TODO: set replace
batch_size = num_gpus * imgs_per_gpu
num_workers = num_gpus * workers_per_gpu
data_loader = DataLoader(
dataset,
batch_size=batch_size,
sampler=sampler,
num_workers=num_workers,
collate_fn=partial(collate, samples_per_gpu=imgs_per_gpu),
pin_memory=False,
worker_init_fn=worker_init_fn if seed is not None else None,
**kwargs)
return data_loader
def worker_init_fn(seed):
np.random.seed(seed)
random.seed(seed)