DBNet / DB /data /data_loader.py
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import math
import bisect
import imgaug
import numpy as np
import torch
import torch.distributed as dist
from torch.utils.data import Sampler, ConcatDataset, BatchSampler
from concern.config import Configurable, State
def default_worker_init_fn(worker_id):
np.random.seed(worker_id)
imgaug.seed(worker_id)
class DataLoader(Configurable, torch.utils.data.DataLoader):
dataset = State()
batch_size = State(default=256)
num_workers = State(default=10)
is_train = State(default=True)
collect_fn = State(default=None)
drop_last = State(default=True)
shuffle = State()
def __init__(self, **kwargs):
self.load_all(**kwargs)
if self.collect_fn is None:
self.collect_fn = torch.utils.data.dataloader.default_collate
cmd = kwargs.get('cmd', {})
self.is_train = cmd['is_train']
if 'batch_size' in cmd:
self.batch_size = cmd['batch_size']
if self.shuffle is None:
self.shuffle = self.is_train
self.num_workers = cmd.get('num_workers', self.num_workers)
if cmd.get('distributed'):
sampler = DistributedSampler(
self.dataset, shuffle=self.shuffle,
num_replicas=cmd['num_gpus'])
batch_sampler = BatchSampler(
sampler, self.batch_size//cmd['num_gpus'], False)
torch.utils.data.DataLoader.__init__(
self, self.dataset, batch_sampler=batch_sampler,
num_workers=self.num_workers, pin_memory=False,
drop_last=self.drop_last, collate_fn=self.collect_fn,
worker_init_fn=default_worker_init_fn)
else:
torch.utils.data.DataLoader.__init__(
self, self.dataset,
batch_size=self.batch_size, num_workers=self.num_workers,
drop_last=self.drop_last, shuffle=self.shuffle,
pin_memory=True, collate_fn=self.collect_fn,
worker_init_fn=default_worker_init_fn)
self.collect_fn = str(self.collect_fn)
class SuccessiveRandomSampler(Sampler):
'''Random Sampler that yields sorted data in successive ranges.
Args:
dataset: Dataset used for sampling.
'''
def __init__(self, dataset):
self.dataset = dataset
self.epoch = 0
def __iter__(self):
if self.shuffle:
# deterministically shuffle based on epoch
g = torch.Generator()
g.manual_seed(self.epoch)
indices = torch.randperm(len(self.dataset)).tolist()
else:
indices = torch.arange(len(self.dataset)).tolist()
# add extra samples to make it evenly divisible
indices += indices[: (self.total_size - len(indices))]
assert len(indices) == self.total_size
# subsample
offset = self.num_samples * self.rank
indices = indices[offset: offset + self.num_samples]
assert len(indices) == self.num_samples
return iter(indices)
def __len__(self):
return len(self.dataset)
def set_epoch(self, epoch):
self.epoch = epoch
class DistributedSampler(Sampler):
"""Sampler that restricts data loading to a subset of the dataset.
It is especially useful in conjunction with
:class:`torch.nn.parallel.DistributedDataParallel`. In such case, each
process can pass a DistributedSampler instance as a DataLoader sampler,
and load a subset of the original dataset that is exclusive to it.
.. note::
Dataset is assumed to be of constant size.
Arguments:
dataset: Dataset used for sampling.
num_replicas (optional): Number of processes participating in
distributed training.
rank (optional): Rank of the current process within num_replicas.
"""
def __init__(self, dataset, num_replicas=None, rank=None, shuffle=True):
if num_replicas is None:
if not dist.is_available():
raise RuntimeError(
"Requires distributed package to be available")
num_replicas = dist.get_world_size()
if rank is None:
if not dist.is_available():
raise RuntimeError(
"Requires distributed package to be available")
rank = dist.get_rank()
self.dataset = dataset
self.num_replicas = num_replicas
self.rank = rank
self.epoch = 0
self.num_samples = int(
math.ceil(len(self.dataset) * 1.0 / self.num_replicas))
self.total_size = self.num_samples * self.num_replicas
self.shuffle = shuffle
def __iter__(self):
if self.shuffle:
# deterministically shuffle based on epoch
g = torch.Generator()
g.manual_seed(self.epoch)
indices = torch.randperm(len(self.dataset)).tolist()
else:
indices = torch.arange(len(self.dataset)).tolist()
# add extra samples to make it evenly divisible
indices += indices[: (self.total_size - len(indices))]
assert len(indices) == self.total_size
# subsample
offset = self.num_samples * self.rank
indices = indices[offset: offset + self.num_samples]
assert len(indices) == self.num_samples
return iter(indices)
def __len__(self):
return self.num_samples
def set_epoch(self, epoch):
self.epoch = epoch
class InfiniteOrderedSampler(Sampler):
def __init__(self, data_source, limit_size):
self.data_source = data_source
self.limit_size = limit_size
def __iter__(self):
n = len(self.data_source)
def wrapper():
cnt = 0
while cnt < self.limit_size:
if cnt % n == 0:
idx = torch.randperm(n).tolist()
yield idx[cnt % n]
cnt += 1
return wrapper()
def __len__(self):
return self.limit_size
class InfiniteDataLoader(Configurable, torch.utils.data.DataLoader):
dataset = State()
batch_size = State(default=256)
num_workers = State(default=10)
limit_size = State(default=2 ** 31)
def __init__(self, **kwargs):
self.load_all(**kwargs)
cmd = kwargs['cmd']
if 'batch_size' in cmd:
self.batch_size = cmd['batch_size']
sampler = InfiniteOrderedSampler(self.dataset, self.limit_size)
torch.utils.data.DataLoader.__init__(
self, self.dataset,
batch_size=self.batch_size, num_workers=self.num_workers,
sampler=sampler, worker_init_fn=default_worker_init_fn,
)
class RandomSampleSampler(Sampler):
def __init__(self, data_source, weights=None, size=2 ** 31):
self.data_source = data_source
if weights is None:
self.probabilities = np.full(len(data_source), 1 / len(data_source))
else:
self.probabilities = np.array(weights) / np.sum(weights)
self.cum_prob = np.cumsum(self.probabilities)
self.size = size
def __iter__(self):
def wrapper():
for i in range(self.size):
yield bisect.bisect(self.cum_prob, torch.rand(1)[0], hi=len(self.data_source) - 1)
return wrapper()
def __len__(self):
return self.size
class RandomSampleDataLoader(Configurable, torch.utils.data.DataLoader):
datasets = State()
weights = State()
batch_size = State(default=256)
num_workers = State(default=10)
size = State(default=2 ** 31)
def __init__(self, **kwargs):
self.load_all(**kwargs)
cmd = kwargs['cmd']
if 'batch_size' in cmd:
self.batch_size = cmd['batch_size']
probs = []
for dataset, weight in zip(self.datasets, self.weights):
probs.append(np.full(len(dataset), weight / len(dataset)))
dataset = ConcatDataset(self.datasets)
probs = np.concatenate(probs)
assert(len(dataset) == len(probs))
sampler = RandomSampleSampler(dataset, probs, self.size)
torch.utils.data.DataLoader.__init__(
self, dataset,
batch_size=self.batch_size, num_workers=self.num_workers,
sampler=sampler, worker_init_fn=default_worker_init_fn,
)