fast-reid/fastreid/data/build.py

105 lines
3.4 KiB
Python

# encoding: utf-8
"""
@author: l1aoxingyu
@contact: sherlockliao01@gmail.com
"""
import os
import torch
from torch._six import container_abcs, string_classes, int_classes
from torch.utils.data import DataLoader
from fastreid.utils import comm
from . import samplers
from .common import CommDataset
from .datasets import DATASET_REGISTRY
from .transforms import build_transforms
_root = os.getenv("FASTREID_DATASETS", "datasets")
def build_reid_train_loader(cfg):
train_transforms = build_transforms(cfg, is_train=True)
train_items = list()
for d in cfg.DATASETS.NAMES:
dataset = DATASET_REGISTRY.get(d)(root=_root, combineall=cfg.DATASETS.COMBINEALL)
if comm.is_main_process():
dataset.show_train()
train_items.extend(dataset.train)
train_set = CommDataset(train_items, train_transforms, relabel=True)
num_workers = cfg.DATALOADER.NUM_WORKERS
num_instance = cfg.DATALOADER.NUM_INSTANCE
mini_batch_size = cfg.SOLVER.IMS_PER_BATCH // comm.get_world_size()
if cfg.DATALOADER.PK_SAMPLER:
if cfg.DATALOADER.NAIVE_WAY:
data_sampler = samplers.NaiveIdentitySampler(train_set.img_items,
cfg.SOLVER.IMS_PER_BATCH, num_instance)
else:
data_sampler = samplers.BalancedIdentitySampler(train_set.img_items,
cfg.SOLVER.IMS_PER_BATCH, num_instance)
else:
data_sampler = samplers.TrainingSampler(len(train_set))
batch_sampler = torch.utils.data.sampler.BatchSampler(data_sampler, mini_batch_size, True)
train_loader = torch.utils.data.DataLoader(
train_set,
num_workers=num_workers,
batch_sampler=batch_sampler,
collate_fn=fast_batch_collator,
)
return train_loader
def build_reid_test_loader(cfg, dataset_name):
test_transforms = build_transforms(cfg, is_train=False)
dataset = DATASET_REGISTRY.get(dataset_name)(root=_root)
if comm.is_main_process():
dataset.show_test()
test_items = dataset.query + dataset.gallery
test_set = CommDataset(test_items, test_transforms, relabel=False)
mini_batch_size = cfg.TEST.IMS_PER_BATCH // comm.get_world_size()
data_sampler = samplers.InferenceSampler(len(test_set))
batch_sampler = torch.utils.data.BatchSampler(data_sampler, mini_batch_size, False)
test_loader = DataLoader(
test_set,
batch_sampler=batch_sampler,
num_workers=0, # save some memory
collate_fn=fast_batch_collator)
return test_loader, len(dataset.query)
def trivial_batch_collator(batch):
"""
A batch collator that does nothing.
"""
return batch
def fast_batch_collator(batched_inputs):
"""
A simple batch collator for most common reid tasks
"""
elem = batched_inputs[0]
if isinstance(elem, torch.Tensor):
out = torch.zeros((len(batched_inputs), *elem.size()), dtype=elem.dtype)
for i, tensor in enumerate(batched_inputs):
out[i] += tensor
return out
elif isinstance(elem, container_abcs.Mapping):
return {key: fast_batch_collator([d[key] for d in batched_inputs]) for key in elem}
elif isinstance(elem, float):
return torch.tensor(batched_inputs, dtype=torch.float64)
elif isinstance(elem, int_classes):
return torch.tensor(batched_inputs)
elif isinstance(elem, string_classes):
return batched_inputs