def act(self, observation: Any, reward: Any, done: bool, info: Optional[Dict[Any, Any]] = None) -> Any:
obs = torch.from_numpy(observation.astype(np.float32))
forward = self.module.forward(obs) # type: ignore
probas = F.softmax(forward, dim=0)
if self.deterministic:
return probas.max(0)[1].view(1, 1).item()
else:
return next(iter(WeightedRandomSampler(probas, 1)))
def build_balanced_sampler(labels, dataset_size=None):
if dataset_size is None:
dataset_size = len(labels)
weights_per_class = [1/x for x in Counter(labels).values()]
weights_per_example = [weights_per_class[c] for c in labels]
return WeightedRandomSampler(weights_per_example, dataset_size, replacement=True)
def set_weights(self):
""" sets the weights from the weighted dataset """
# Make train/val weights
self.train_weights = self.data_weighter.weighting_function(
self.prop_train)
self.val_weights = self.data_weighter.weighting_function(self.prop_val)
# Create samplers
self.train_sampler = WeightedRandomSampler(self.train_weights,
num_samples=len(
self.train_weights),
replacement=True)
self.val_sampler = WeightedRandomSampler(self.val_weights,
num_samples=len(
self.val_weights),
replacement=True)
def get_dataloaders(data_dir,
patch_size: int,
box_coder,
train_batch_size=1,
valid_batch_size=1,
workers=4,
fold=0,
fast=False):
train_ids, valid_ids = get_train_test_split_for_fold(fold, ships_only=True)
if fast:
train_ids = train_ids[:train_batch_size * 64]
valid_ids = valid_ids[:valid_batch_size * 64]
groundtruth = pd.read_csv(
os.path.join(data_dir, 'train_ship_segmentations_v2.csv'))
trainset = D.RSSDDataset(sample_ids=train_ids,
data_dir=data_dir,
transform=get_transform(training=True,
width=patch_size,
height=patch_size),
groundtruth=groundtruth,
box_coder=box_coder)
validset = D.RSSDDataset(sample_ids=valid_ids,
data_dir=data_dir,
transform=get_transform(training=False,
width=patch_size,
height=patch_size),
groundtruth=groundtruth,
box_coder=box_coder)
shuffle = True
sampler = None
if fast:
shuffle = False
sampler = WeightedRandomSampler(np.ones(len(trainset)), 1024)
trainloader = DataLoader(trainset,
batch_size=train_batch_size,
num_workers=workers,
pin_memory=True,
drop_last=True,
shuffle=shuffle,
sampler=sampler)
validloader = DataLoader(
validset,
batch_size=valid_batch_size,
num_workers=workers,
pin_memory=True,
drop_last=False,
shuffle=False,
)
print('Train set', len(trainset), len(trainloader), 'Valid set',
len(validset), len(validloader))
return trainloader, validloader
def load_data():
print("initializing dataloader")
transforms_video = [
CenterCrop(opt.image_size),
RGB2Lab(),
ToTensor(),
Normalize(),
]
transforms_imagenet = [
CenterPad_threshold(opt.image_size),
RGB2Lab(),
ToTensor(),
Normalize()
]
extra_reference_transform = [
transform_lib.RandomHorizontalFlip(0.5),
transform_lib.RandomResizedCrop(480, (0.98, 1.0), ratio=(0.8, 1.2)),
]
train_dataset_video = VideosDataset(
data_root=opt.data_root,
epoch=opt.epoch,
image_size=opt.image_size,
image_transform=transforms.Compose(transforms_video),
real_reference_probability=opt.real_reference_probability,
nonzero_placeholder_probability=opt.nonzero_placeholder_probability,
)
train_dataset_imagenet = VideosDataset_ImageNet(
data_root=opt.data_root_imagenet,
image_size=opt.image_size,
epoch=opt.epoch,
with_bad=opt.with_bad,
with_mid=opt.with_mid,
transforms_imagenet=transforms_imagenet,
distortion_level=4,
brightnessjitter=5,
nonzero_placeholder_probability=opt.nonzero_placeholder_probability,
extra_reference_transform=extra_reference_transform,
real_reference_probability=opt.real_reference_probability,
)
video_training_length = len(train_dataset_video)
imagenet_training_length = len(train_dataset_imagenet)
dataset_training_length = train_dataset_video.real_len + train_dataset_imagenet.real_len
dataset_combined = ConcatDataset(
[train_dataset_video, train_dataset_imagenet])
sampler = WeightedRandomSampler([1] * video_training_length +
[1] * imagenet_training_length,
dataset_training_length * opt.epoch)
data_loader = DataLoader(
dataset_combined,
batch_size=opt.batch_size,
shuffle=False,
num_workers=opt.workers,
pin_memory=True,
drop_last=True,
sampler=sampler,
)
return dataset_training_length, train_dataset_video, train_dataset_imagenet, data_loader
def get_class_balanced_sampler(
dataset
):
assert isinstance(dataset, ClassDataset), 'dataset is an instance of ClassDataset.'
indices = list(range(len(dataset)))
num_samples = len(dataset)
weights = [1.0 / dataset.per_label_records_num[dataset[index][3].item()] for index in indices]
weights = torch.tensor(weights)
return WeightedRandomSampler(weights, num_samples)
def my_sampler(target):
class_sample_count = np.array([len(np.where(target == t)[0]) for t in np.unique(target)])
weight = 1. / class_sample_count
samples_weight = np.array([weight[t] for t in target])
samples_weight = torch.from_numpy(samples_weight)
samples_weigth = samples_weight.double()
sampler = WeightedRandomSampler(samples_weight, len(samples_weight))
return sampler
def create_weighted_sampler(labels):
labels_unique, counts = np.unique(labels, return_counts=True)
class_weights = [sum(counts) / c for c in counts]
#class_weights[1] = class_weights[1]/2
example_weights = [class_weights[int(e)] for e in labels]
#print("Example Weights:")
#print(example_weights)
sampler = WeightedRandomSampler(example_weights, len(labels))
return sampler
def prepare_random_sampler(classes_list):
class_sample_count = np.array(
[len(np.where(classes_list == t)[0]) for t in np.unique(classes_list)])
weight = 1. / class_sample_count
samples_weight = np.array([weight[t] for t in classes_list])
samples_weight = torch.from_numpy(samples_weight)
samples_weight = samples_weight.double()
sampler = WeightedRandomSampler(samples_weight, len(samples_weight))
return sampler
def get_iwildcam_loader(cfg, mode='train'):
print("Mode: {}".format(mode))
if mode == 'train' or mode == 'train_val' or mode == 'train_dev': # train_val
train_data = iWildCam(cfg, mode=mode) # 定义一个取数据的 迭代器
if cfg.TRAIN.WEIGHT_SAMPLER:
train_sampler = WeightedRandomSampler(train_data.samples_weight,
train_data.__len__())
train_loader = torch.utils.data.DataLoader(
train_data,
batch_size=cfg.TRAIN.BATCH_SIZE,
num_workers=cfg.TRAIN.NUM_WORKER,
drop_last=True,
pin_memory=True,
sampler=train_sampler)
else:
train_loader = torch.utils.data.DataLoader(
train_data,
batch_size=cfg.TRAIN.BATCH_SIZE,
shuffle=True,
num_workers=cfg.TRAIN.NUM_WORKER,
drop_last=True,
pin_memory=True)
dev_data = iWildCam(cfg, mode='dev') # eval的数据
dev_loader = torch.utils.data.DataLoader(
dev_data,
batch_size=cfg.TRAIN.EVAL_BATCH_SIZE,
shuffle=False,
num_workers=cfg.TRAIN.NUM_WORKER,
drop_last=False,
pin_memory=True)
return train_loader, dev_loader
elif mode in ['infer', 'infer_by_seq', 'infer_by_seqv2']:
test_data = iWildCam(cfg, mode=mode)
test_loader = torch.utils.data.DataLoader(
test_data,
batch_size=cfg.TRAIN.BATCH_SIZE,
shuffle=False,
num_workers=cfg.TRAIN.NUM_WORKER,
drop_last=False,
pin_memory=True)
return test_loader
elif mode == 'val': # 仅用于验证模型的性能
val_data = iWildCam(cfg, mode='dev') # eval的数据
val_loader = torch.utils.data.DataLoader(
val_data,
batch_size=cfg.TRAIN.EVAL_BATCH_SIZE,
shuffle=False,
num_workers=cfg.TRAIN.NUM_WORKER,
drop_last=False,
pin_memory=True)
return val_loader
else:
return None
def create_dataloaders(X_train, y_train, X_valid, y_valid, weights, batch_size,
num_workers, drop_last):
"""
Create dataloaders with or wihtout subsampling depending on weights and balanced.
Parameters
----------
X_train: np.ndarray
Training data
y_train: np.array
Mapped Training targets
X_valid: np.ndarray
Validation data
y_valid: np.array
Mapped Validation targets
weights : dictionnary or bool
Weight for each mapped target class
0 for no sampling
1 for balanced sampling
Returns
-------
train_dataloader, valid_dataloader : torch.DataLoader, torch.DataLoader
Training and validation dataloaders
"""
if weights == 0:
train_dataloader = DataLoader(TorchDataset(X_train, y_train),
batch_size=batch_size,
shuffle=True,
num_workers=num_workers,
drop_last=drop_last)
else:
if weights == 1:
class_sample_count = np.array(
[len(np.where(y_train == t)[0]) for t in np.unique(y_train)])
weights = 1. / class_sample_count
samples_weight = np.array([weights[t] for t in y_train])
samples_weight = torch.from_numpy(samples_weight)
samples_weight = samples_weight.double()
else:
# custom weights
samples_weight = np.array([weights[t] for t in y_train])
sampler = WeightedRandomSampler(samples_weight, len(samples_weight))
train_dataloader = DataLoader(TorchDataset(X_train, y_train),
batch_size=batch_size,
sampler=sampler,
num_workers=num_workers,
drop_last=drop_last)
valid_dataloader = DataLoader(TorchDataset(X_valid, y_valid),
batch_size=batch_size,
shuffle=False,
num_workers=num_workers)
return train_dataloader, valid_dataloader
def train(self, net, samples, optimizer, e):
alpha = 2 * max(0, ((100 - e) / 100))
criterion = losses.ELULovaszFocalWithLogitsLoss(alpha, 2 - alpha)
transforms = generator.TransformationsGenerator([
random.RandomFlipLr(),
random.RandomAffine(image_size=101,
translation=lambda rs:
(rs.randint(-20, 20), rs.randint(-20, 20)),
scale=lambda rs: (rs.uniform(0.85, 1.15), 1),
**utils.transformations_options),
transformations.Padding(((13, 14), (13, 14), (0, 0)))
])
pseudo_dataset = datasets.SemiSupervisedImageDataset(
samples_test,
settings.test,
transforms,
size=len(samples_test),
test_predictions=self.test_predictions,
momentum=0.0)
dataset = datasets.ImageDataset(samples, settings.train, transforms)
weights = [len(pseudo_dataset) / len(dataset) * 2
] * len(dataset) + [1] * len(pseudo_dataset)
dataloader = DataLoader(ConcatDataset([dataset, pseudo_dataset]),
num_workers=10,
batch_size=16,
sampler=WeightedRandomSampler(
weights=weights, num_samples=3200))
average_meter_train = meters.AverageMeter()
with tqdm(total=len(dataloader),
leave=False) as pbar, torch.enable_grad():
net.train()
for images, masks_targets in dataloader:
masks_targets = masks_targets.to(gpu)
masks_predictions = net(images)
loss = criterion(masks_predictions, masks_targets)
loss.backward()
optimizer.step()
optimizer.zero_grad()
average_meter_train.add('loss', loss.item())
self.update_pbar(torch.sigmoid(masks_predictions),
masks_targets, pbar, average_meter_train,
'Training epoch {}'.format(e))
train_stats = {
'train_' + k: v
for k, v in average_meter_train.get_all().items()
}
return train_stats
def __init__(self):
##The top config
#self.data_root = '/media/hhy/data/USdata/MergePhase1/test_0.3'
#self.log_dir = '/media/hhy/data/code_results/MILs/MIL_H_Attention'
self.root = '/remote-home/my/Ultrasound_CV/data/Ruijin/clean'
self.log_dir = '/remote-home/my/hhy/Ultrasound_MIL/experiments/weighted_sampler/'
if not os.path.exists(self.log_dir):
os.makedirs(self.log_dir)
##training config
self.lr = 1e-4
self.epoch = 50
self.resume = -1
self.batch_size = 1
self.net = Attention()
self.net.cuda()
self.optimizer = Adam(self.net.parameters(), lr=self.lr)
self.lrsch = torch.optim.lr_scheduler.MultiStepLR(self.optimizer, milestones=[10, 30, 50, 70], gamma=0.5)
self.logger = Logger(self.log_dir)
self.train_transform = transforms.Compose([
transforms.Resize((224,224)),
transforms.RandomResizedCrop((224,224)),
transforms.RandomHorizontalFlip(0.5),
transforms.RandomVerticalFlip(0.5),
transforms.ColorJitter(0.25,0.25,0.25,0.25),
transforms.ToTensor()
])
self.test_transform = transforms.Compose([
transforms.Resize((224,224)),
transforms.ToTensor()
])
self.trainbag = RuijinBags(self.root, [0,1,2,3],self.train_transform)
self.testbag = RuijinBags(self.root, [4], self.test_transform)
train_label_list = list(map(lambda x: int(x['label']), self.trainbag.patient_info))
pos_ratio = sum(train_label_list) / len(train_label_list)
print(pos_ratio)
train_weight = [(1-pos_ratio) if x>0 else pos_ratio for x in train_label_list]
self.train_sampler = WeightedRandomSampler(weights=train_weight, num_samples=len(self.trainbag))
self.train_loader = DataLoader(self.trainbag, batch_size=self.batch_size, num_workers=8,
sampler=self.train_sampler)
self.val_loader = DataLoader(self.testbag, batch_size=self.batch_size, shuffle=False, num_workers=8)
if self.resume > 0:
self.net, self.optimizer, self.lrsch, self.loss, self.global_step = self.logger.load(self.net, self.optimizer, self.lrsch, self.loss, self.resume)
else:
self.global_step = 0
# self.trainer = MTTrainer(self.net, self.optimizer, self.lrsch, self.loss, self.train_loader, self.val_loader, self.logger, self.global_step, mode=2)
self.trainer = MILTrainer_batch1(self.net, self.optimizer, self.lrsch, None, self.train_loader, self.val_loader, self.logger,
self.global_step)
def prepare_data():
#2.1 get files and split for K-fold dataset
#2.1.1 read files
train_ = get_files(config.train_data, "train")
#val_data_list = get_files(config.val_data,"val")
test_files = get_files(config.test_data, "test")
"""
#2.1.2 split
split_fold = StratifiedKFold(n_splits=3)
folds_indexes = split_fold.split(X=origin_files["filename"],y=origin_files["label"])
folds_indexes = np.array(list(folds_indexes))
fold_index = folds_indexes[fold]
#2.1.3 using fold index to split for train data and val data
train_data_list = pd.concat([origin_files["filename"][fold_index[0]],origin_files["label"][fold_index[0]]],axis=1)
val_data_list = pd.concat([origin_files["filename"][fold_index[1]],origin_files["label"][fold_index[1]]],axis=1)
"""
train_data_list, val_data_list = train_test_split(train_,
test_size=0.15,
stratify=train_["label"])
#2.1.4 load dataset
#2.1.4.1 sampling
train_dataset, val_dataset, test_dataset = AgriDataset(
train_data_list), AgriDataset(val_data_list,
train=False), AgriDataset(test_files,
test=True)
if config.ifWeightedRandomShuffle is True:
distribution = train_data_list.groupby(by=['label']).size()
banlance = min(distribution)
dic = {}
for i in range(len(distribution)):
dic[i] = distribution[i]
weights = []
for i in range(len(train_dataset)):
weights.append(banlance / dic[train_dataset[i][1]])
sampler = WeightedRandomSampler(weights,\
num_samples=len(weights),\
replacement=True)
train_dataloader = DataLoader(train_dataset, batch_size=config.batch_size,\
collate_fn=collate_fn,pin_memory=True,sampler=sampler)
else:
train_dataloader = DataLoader(train_dataset,
batch_size=config.batch_size,
shuffle=True,
collate_fn=collate_fn,
pin_memory=True)
val_dataloader = DataLoader(val_dataset,
batch_size=config.batch_size,
shuffle=True,
collate_fn=collate_fn,
pin_memory=False)
test_dataloader = DataLoader(test_dataset,
batch_size=1,
shuffle=False,
pin_memory=False)
return train_dataloader, val_dataloader, test_dataloader
def sampler(self, mode: str, dataset: Dataset) -> Sampler:
if "train" in mode:
if self.config.DEBUG:
return WeightedRandomSampler(
weights=np.ones(len(dataset)),
num_samples=self.config.DEBUG_TRAIN_SIZE)
else:
return RandomSampler(dataset, replacement=False)
else:
return SequentialSampler(dataset)
def create_data_loader(dataset, counters, parameters, init_sampler):
labels = [label for _, label in dataset.the_list]
class_weights = [dataset.__len__() / counters[label] for label in label_names().values()]
weights = [class_weights[labels[i]] for i in range(dataset.__len__())]
if init_sampler:
sampler = WeightedRandomSampler(weights=weights, num_samples=dataset.__len__())
data_loader = DataLoader(dataset=dataset, batch_size=parameters['batch_size'], sampler=sampler)
else:
data_loader = DataLoader(dataset=dataset, batch_size=parameters['batch_size'])
return data_loader
def resampling_balance(data):
targets = data.target
class_count = np.unique(targets, return_counts=True)[1]
print("Class number before resampling: ", class_count)
weight = 1. / class_count
samples_weight = weight[targets]
samples_weight = torch.from_numpy(samples_weight)
sampler = WeightedRandomSampler(samples_weight, len(samples_weight))
return sampler
def forward(self, bsz, seq_len, cuda=True):
# returns bsz*seq_len*nsamples samples in shape nsamples x (bsz x seq_len)
# sample based on frequencies
wrs = WeightedRandomSampler(self.frequencies,
self.nsamples * bsz * seq_len)
samples = torch.LongTensor(
list(wrs)).cuda() if cuda else torch.LongTensor(list(wrs))
return samples.view(-1, bsz)
def __init__(self, danspeech_multi_dataset, num_replicas=None, rank=None):
super(DistributedWeightedSamplerCustom,
self).__init__(danspeech_multi_dataset,
num_replicas=num_replicas,
rank=rank,
shuffle=False)
self.sampler = WeightedRandomSampler(
danspeech_multi_dataset.final_weights,
len(danspeech_multi_dataset))
self.epoch = 0
def get(self):
"""Obtains an instance of the sampler. """
gen = torch.Generator()
gen.manual_seed(self.random_seed)
# Samples without replacement using the sample weights
return WeightedRandomSampler(weights=self.sample_weights,
num_samples=self.partition_size,
replacement=False,
generator=gen)
def _create_sampler(self, target_np):
self.labels = np.unique(target_np)
class_sample_count = np.array(
[len(np.where(target_np == t)[0]) for t in self.labels])
weight = 1. / class_sample_count
samples_weight = torch.from_numpy(
np.array([weight[t] for t in target_np])).double()
return WeightedRandomSampler(samples_weight,
len(samples_weight),
replacement=True)
def _construct_dataloaders(self):
dataloaders = []
for dataset, weights in zip(self._datasets, self._weights):
sampler = WeightedRandomSampler(weights, len(weights))
dataloaders.append(
DataLoader(dataset=dataset,
sampler=sampler,
num_workers=self._num_workers,
batch_size=self._batch_size))
return [iter(loader) for loader in dataloaders]
def _get_balanced_dev_dataloader(self, dataset, drop_last=False):
return DataLoader(
dataset,
sampler=WeightedRandomSampler(dataset.sample_weights,
len(dataset.sample_weights)),
batch_size=self.datarc["batch_size"],
drop_last=drop_last,
num_workers=self.datarc["num_workers"],
collate_fn=dataset.collate_fn,
)
def balance_sources_sampler(dataset, strength):
srcs = dataset.sources
sources_count = [list(srcs.values()).count(source) for source in set(list(srcs.values()))]
sources_count_dict = dict(zip(list(set(list(srcs.values()))), sources_count))
weights = [1/(sources_count_dict[srcs[image_id]] + 1.0 / strength) for image_id in list(srcs.keys())]
sampler = WeightedRandomSampler(weights, len(dataset))
return sampler
def _get_sampler(df: pd.DataFrame, alpha: float = 0.5) -> Sampler:
y = np.array(
[HumanProteinDataset.parse_target(target) for target in df.Target])
class_weights = np.round(np.log(alpha * y.sum() / y.sum(axis=0)), 2)
class_weights[class_weights < 1.0] = 1.0
weights = np.zeros(len(df))
for i, target in enumerate(y):
weights[i] = class_weights[target == 1].max()
return WeightedRandomSampler(weights, len(df))
def k_fold(logger,k,root,val_root,epoch,args,critertion,optimizer,k_model,device,loss_meter,confusion_matrix,train_acc,loss_list,val_acc):
trained_time = 0
best_accracy = 0
best_model = None
avg_accuracy = 0
avg_loss = 0
avg_train_acc = 0
end = time.time()
for i in range(k):
get_k_fold_data(k,i,'dataset/all_shuffle_datas.txt')
train_transform = train_augment(cfg.IMAGE_SIZE)
train_data=Eye(img_root=root,tag_root='dataset/train_k.txt',transform=train_transform)
data_len=train_data.__len__()
weight_prob=[data_len/w for w in [1,6,1,1,0.4,0.8,2.5]]
weight_list=[weight_prob[label] for data,label in train_data]
train_sampler = WeightedRandomSampler(weights=weight_list,num_samples=7*2000,replacement=True)
train_dataloader=DataLoader(train_data,batch_size=cfg.BATCHSIZE,shuffle=(train_sampler==None),drop_last=True,sampler=train_sampler,num_workers=8)
val_transform = val_augment(cfg.IMAGE_SIZE)
val_data=Eye(img_root=root,tag_root='dataset/val_k.txt',transform=val_transform)
val_dataloader=DataLoader(val_data,batch_size=cfg.BATCHSIZE,shuffle=False,drop_last=True,num_workers=8)
k_model[i],train_loss,train_accuracy = train(train_dataloader,critertion,optimizer,k_model[i],device,loss_meter,confusion_matrix)
val_cm,val_accuracy = val(k_model[i],val_dataloader,device)
avg_accuracy+=val_accuracy
avg_train_acc+=train_accuracy
avg_loss+=train_loss
trained_time = time.time() - end
end = time.time()
log_str = [
"Epoch:{:02d}, Fold:{:02d}, Lr:{:.8f}, Cost:{:.2f}s".format(epoch,i,
optimizer.param_groups[0]['lr'], trained_time),
"Loss:{:.2f}".format(train_loss),
"train_acc:{:.2f}".format(train_accuracy),
"val_acc:{:.2f}".format(val_accuracy)
]
logger.info(log_str)
if val_accuracy>best_accracy:
best_model = k_model[i]
avg_accuracy = avg_accuracy/k
avg_train_acc = avg_train_acc/k
avg_loss = avg_loss/k
val_acc.append(avg_accuracy)
train_acc.append(avg_train_acc)
loss_list.append(avg_loss)
log_str = "Epoch:{:2d}".format(epoch)+"--"+"avg_loss:{:2f}".format(avg_loss)+"--"+"avg_train_accuracy:{:2f}".format(avg_train_acc)+"--"+"avg_val_accuracy:{:2f}".format(avg_accuracy)
logger.info(log_str)
t.save(best_model.state_dict(),os.path.join(cfg.OUTPUT_MODEL_DIR, args.model+'test{:2d}.pth'.format(epoch)))
return k_model
def get_class_balanced_sampler(dataset):
if not hasattr(dataset, 'per_label_records_num'):
return RandomSampler(dataset)
indices = list(range(len(dataset)))
num_samples = len(dataset)
weights = [
1.0 / dataset.per_label_records_num[dataset[index][3].item()]
for index in indices
]
weights = torch.tensor(weights)
return WeightedRandomSampler(weights, num_samples)
def train_dataloader(self) -> DataLoader:
sourceSet = self.dataSets['source']
targetSet = self.dataSets['targetTrain']
STSet = ConcatDataset([sourceSet, targetSet])
source_weights = [1.0 / len(sourceSet) for _ in range(len(sourceSet))]
target_weights = [1.0 / len(targetSet) for _ in range(len(targetSet))]
weights = [*source_weights, *target_weights]
sampler = WeightedRandomSampler(weights=weights, num_samples=len(STSet), replacement=True)
return DataLoader(STSet, sampler=sampler, batch_size=self.batch_size, num_workers=self.num_workers)
def class_imbalance_sampler(targets, segmentation_threshold):
if len(targets.shape) > 1: # if posed as segmentation task
targets = targets.sum(axis=1) / targets.shape[1]
targets = targets > segmentation_threshold
targets = tensor(targets).long().squeeze()
class_count = torch.bincount(targets)
weighting = tensor(1.) / class_count.float()
weights = weighting[targets]
sampler = WeightedRandomSampler(weights, len(targets))
return sampler
def create_sampler(self):
class_weights = self.train_data.train['class'].value_counts().to_dict()
for k, v in class_weights.items():
class_weights[k] = 1. / torch.tensor(v, dtype=torch.float)
sample_weights = [0] * len(self.train_data.train)
for idx, label in enumerate(self.train_data.train['class']):
sample_weights[idx] = class_weights[label]
return WeightedRandomSampler(sample_weights,
num_samples=len(sample_weights),
replacement=True)