class ActiveLearning(torch.nn.Module):
def __init__(self, exp_dict):
super().__init__()
self.backbone = models.vgg16(
pretrained=exp_dict["imagenet_pretraining"], progress=True)
num_ftrs = self.backbone.classifier[-1].in_features
self.backbone.classifier[-1] = torch.nn.Linear(num_ftrs,
exp_dict["num_classes"])
self.backbone = patch_module(self.backbone)
self.initial_weights = deepcopy(self.backbone.state_dict())
self.backbone.cuda()
self.batch_size = exp_dict['batch_size']
self.calibrate = exp_dict.get('calibrate', False)
self.learning_epoch = exp_dict['learning_epoch']
self.optimizer = torch.optim.SGD(self.backbone.parameters(),
lr=exp_dict['lr'],
weight_decay=5e-4,
momentum=0.9,
nesterov=True)
self.criterion = CrossEntropyLoss()
shuffle_prop = exp_dict.get('shuffle_prop', 0.0)
max_sample = -1
self.heuristic = get_heuristic(exp_dict['heuristic'],
shuffle_prop=shuffle_prop)
self.wrapper = ModelWrapper(self.backbone, criterion=self.criterion)
self.wrapper.add_metric(
'cls_report',
lambda: ClassificationReport(exp_dict["num_classes"]))
self.wrapper.add_metric('accuracy', lambda: Accuracy())
self.loop = ActiveLearningLoop(None,
self.wrapper.predict_on_dataset,
heuristic=self.heuristic,
ndata_to_label=exp_dict['query_size'],
batch_size=self.batch_size,
iterations=exp_dict['iterations'],
use_cuda=True,
max_sample=max_sample)
self.calib_set = get_dataset('calib', exp_dict['dataset'])
self.valid_set = get_dataset('val', exp_dict['dataset'])
self.calibrator = DirichletCalibrator(
self.wrapper,
exp_dict["num_classes"],
lr=0.001,
reg_factor=exp_dict['reg_factor'],
mu=exp_dict['mu'])
self.active_dataset = None
self.active_dataset_settings = None
def train_on_loader(self, loader: DataLoader):
self.wrapper.load_state_dict(self.initial_weights)
if self.active_dataset is None:
self.active_dataset = loader.dataset
if self.active_dataset_settings is not None:
self.active_dataset.load_state_dict(
self.active_dataset_settings)
self.loop.dataset = self.active_dataset
self.criterion.train()
self.wrapper.train_on_dataset(self.active_dataset,
self.optimizer,
self.batch_size,
epoch=self.learning_epoch,
use_cuda=True)
metrics = self.wrapper.metrics
return self._format_metrics(metrics, 'train')
def val_on_loader(self, loader, savedir=None):
val_data = loader.dataset
self.loop.step()
self.criterion.eval()
self.wrapper.test_on_dataset(val_data,
batch_size=self.batch_size,
use_cuda=True,
average_predictions=20)
metrics = self.wrapper.metrics
mets = self._format_metrics(metrics, 'test')
mets.update({'num_samples': len(self.active_dataset)})
return mets
def on_train_end(self, savedir, epoch):
h5_path = pjoin(savedir, 'ckpt.h5')
labelled = self.active_dataset.state_dict()['labelled']
with h5py.File(h5_path, 'a') as f:
if f'epoch_{epoch}' not in f:
g = f.create_group(f'epoch_{epoch}')
g.create_dataset('labelled', data=labelled.astype(np.bool))
def _format_metrics(self, metrics, step):
mets = {k: v.value for k, v in metrics.items() if step in k}
mets_unpacked = {}
for k, v in mets.items():
if isinstance(v, float):
mets_unpacked[k] = v
elif isinstance(v, np.ndarray):
mets_unpacked[k] = v.mean()
else:
mets_unpacked.update(
{f"{k}_{ki}": np.mean(vi)
for ki, vi in v.items()})
return mets_unpacked
def get_state_dict(self):
state = {}
state["model"] = self.backbone.state_dict()
state["optimizer"] = self.optimizer.state_dict()
if self.active_dataset is None:
state['dataset'] = None
else:
state["dataset"] = self.active_dataset.state_dict()
return state
def set_state_dict(self, state_dict):
self.backbone.load_state_dict(state_dict["model"])
self.optimizer.load_state_dict(state_dict["optimizer"])
self.active_dataset_settings = state_dict["dataset"]
if self.active_dataset is not None:
self.active_dataset.load_state_dict(self.active_dataset_settings)
def main():
args = parse_args()
use_cuda = torch.cuda.is_available()
torch.backends.cudnn.benchmark = True
random.seed(1337)
torch.manual_seed(1337)
if not use_cuda:
print("warning, the experiments would take ages to run on cpu")
hyperparams = vars(args)
active_set, test_set = get_datasets(hyperparams["initial_pool"])
heuristic = get_heuristic(hyperparams["heuristic"],
hyperparams["shuffle_prop"])
criterion = CrossEntropyLoss()
model = vgg16(pretrained=False, num_classes=10)
weights = load_state_dict_from_url(
"https://download.pytorch.org/models/vgg16-397923af.pth")
weights = {k: v for k, v in weights.items() if "classifier.6" not in k}
model.load_state_dict(weights, strict=False)
# change dropout layer to MCDropout
model = patch_module(model)
if use_cuda:
model.cuda()
optimizer = optim.SGD(model.parameters(),
lr=hyperparams["lr"],
momentum=0.9)
# Wraps the model into a usable API.
model = ModelWrapper(model, criterion)
logs = {}
logs["epoch"] = 0
# for prediction we use a smaller batchsize
# since it is slower
active_loop = ActiveLearningLoop(
active_set,
model.predict_on_dataset,
heuristic,
hyperparams.get("query_size", 1),
batch_size=10,
iterations=hyperparams["iterations"],
use_cuda=use_cuda,
)
# We will reset the weights at each active learning step.
init_weights = deepcopy(model.state_dict())
for epoch in tqdm(range(args.epoch)):
# Load the initial weights.
model.load_state_dict(init_weights)
model.train_on_dataset(
active_set,
optimizer,
hyperparams["batch_size"],
hyperparams["learning_epoch"],
use_cuda,
)
# Validation!
model.test_on_dataset(test_set, hyperparams["batch_size"], use_cuda)
metrics = model.metrics
should_continue = active_loop.step()
if not should_continue:
break
val_loss = metrics["test_loss"].value
logs = {
"val": val_loss,
"epoch": epoch,
"train": metrics["train_loss"].value,
"labeled_data": active_set.labelled,
"Next Training set size": len(active_set),
}
print(logs)