import math
import numpy as np
from paddle.io import BatchSampler
[docs]class ErnieSATSampler(BatchSampler):
"""Sampler that restricts data loading to a subset of the dataset.
In such case, each process can pass a DistributedBatchSampler 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.
Args:
dataset(paddle.io.Dataset): this could be a `paddle.io.Dataset` implement
or other python object which implemented
`__len__` for BatchSampler to get sample
number of data source.
batch_size(int): sample indice number in a mini-batch indices.
num_replicas(int, optional): porcess number in distributed training.
If :attr:`num_replicas` is None, :attr:`num_replicas` will be
retrieved from :code:`paddle.distributed.ParallenEnv`.
Default None.
rank(int, optional): the rank of the current process among :attr:`num_replicas`
processes. If :attr:`rank` is None, :attr:`rank` is retrieved from
:code:`paddle.distributed.ParallenEnv`. Default None.
shuffle(bool): whther to shuffle indices order before genrating
batch indices. Default False.
drop_last(bool): whether drop the last incomplete batch dataset size
is not divisible by the batch size. Default False
Examples:
.. code-block:: python
import numpy as np
from paddle.io import Dataset, DistributedBatchSampler
# init with dataset
class RandomDataset(Dataset):
def __init__(self, num_samples):
self.num_samples = num_samples
def __getitem__(self, idx):
image = np.random.random([784]).astype('float32')
label = np.random.randint(0, 9, (1, )).astype('int64')
return image, label
def __len__(self):
return self.num_samples
dataset = RandomDataset(100)
sampler = DistributedBatchSampler(dataset, batch_size=64)
for data in sampler:
# do something
break
"""
def __init__(self,
dataset,
batch_size,
num_replicas=None,
rank=None,
shuffle=False,
drop_last=False):
self.dataset = dataset
assert isinstance(batch_size, int) and batch_size > 0, \
"batch_size should be a positive integer"
self.batch_size = batch_size
assert isinstance(shuffle, bool), \
"shuffle should be a boolean value"
self.shuffle = shuffle
assert isinstance(drop_last, bool), \
"drop_last should be a boolean number"
from paddle.distributed import ParallelEnv
if num_replicas is not None:
assert isinstance(num_replicas, int) and num_replicas > 0, \
"num_replicas should be a positive integer"
self.nranks = num_replicas
else:
self.nranks = ParallelEnv().nranks
if rank is not None:
assert isinstance(rank, int) and rank >= 0, \
"rank should be a non-negative integer"
self.local_rank = rank
else:
self.local_rank = ParallelEnv().local_rank
self.drop_last = drop_last
self.epoch = 0
self.num_samples = int(math.ceil(len(self.dataset) * 1.0 / self.nranks))
self.total_size = self.num_samples * self.nranks
def __iter__(self):
num_samples = len(self.dataset)
indices = np.arange(num_samples).tolist()
indices += indices[:(self.total_size - len(indices))]
assert len(indices) == self.total_size
# subsample
def _get_indices_by_batch_size(indices):
subsampled_indices = []
last_batch_size = self.total_size % (self.batch_size * self.nranks)
assert last_batch_size % self.nranks == 0
last_local_batch_size = last_batch_size // self.nranks
for i in range(self.local_rank * self.batch_size,
len(indices) - last_batch_size,
self.batch_size * self.nranks):
subsampled_indices.extend(indices[i:i + self.batch_size])
indices = indices[len(indices) - last_batch_size:]
subsampled_indices.extend(
indices[self.local_rank * last_local_batch_size:(
self.local_rank + 1) * last_local_batch_size])
return subsampled_indices
if self.nranks > 1:
indices = _get_indices_by_batch_size(indices)
assert len(indices) == self.num_samples
_sample_iter = iter(indices)
batch_indices_list = []
batch_indices = []
for idx in _sample_iter:
batch_indices.append(idx)
if len(batch_indices) == self.batch_size:
batch_indices_list.append(batch_indices)
batch_indices = []
if not self.drop_last and len(batch_indices) > 0:
batch_indices_list.append(batch_indices)
if self.shuffle:
np.random.RandomState(self.epoch).shuffle(batch_indices_list)
self.epoch += 1
for batch_indices in batch_indices_list:
yield batch_indices
def __len__(self):
num_samples = self.num_samples
num_samples += int(not self.drop_last) * (self.batch_size - 1)
return num_samples // self.batch_size
[docs] def set_epoch(self, epoch):
"""
Sets the epoch number. When :attr:`shuffle=True`, this number is used
as seeds of random numbers. By default, users may not set this, all
replicas (workers) use a different random ordering for each epoch.
If set same number at each epoch, this sampler will yield the same
ordering at all epoches.
Arguments:
epoch (int): Epoch number.
Examples:
.. code-block:: python
import numpy as np
from paddle.io import Dataset, DistributedBatchSampler
# init with dataset
class RandomDataset(Dataset):
def __init__(self, num_samples):
self.num_samples = num_samples
def __getitem__(self, idx):
image = np.random.random([784]).astype('float32')
label = np.random.randint(0, 9, (1, )).astype('int64')
return image, label
def __len__(self):
return self.num_samples
dataset = RandomDataset(100)
sampler = DistributedBatchSampler(dataset, batch_size=64)
for epoch in range(10):
sampler.set_epoch(epoch)
"""
self.epoch = epoch