def build(cfg, registry, default_args=None):
"""Build a module.
Args:
cfg (dict, list[dict]): The config of modules, is is either a dict
or a list of configs.
registry (:obj:`Registry`): A registry the module belongs to.
default_args (dict, optional): Default arguments to build the module.
Defaults to None.
Returns:
nn.Module: A built nn module.
"""
if isinstance(cfg, list):
modules = [
build_from_cfg(cfg_, registry, default_args) for cfg_ in cfg
]
return nn.Sequential(*modules)
else:
return build_from_cfg(cfg, registry, default_args)
def __init__(self, transforms):
assert isinstance(transforms, Sequence)
self.transforms = []
for transform in transforms:
if isinstance(transform, dict):
transform = build_from_cfg(transform, PIPELINES)
self.transforms.append(transform)
elif callable(transform):
self.transforms.append(transform)
else:
raise TypeError(f'transform must be callable or a dict, '
f'but got {type(transform)}')
def build_dataset(cfg, default_args=None):
dataset = build_from_cfg(cfg, DATASETS, default_args)
return dataset
def build_scheduler(cfg, default_args=None):
scheduler = build_from_cfg(cfg, SCHEDULER, default_args)
return scheduler
def build_loss(cfg):
"""Build loss."""
losses = build_from_cfg(cfg, LOSSES)
return losses
def test_build_from_cfg():
BACKBONES = Registry('backbone')
@BACKBONES.register_module()
class ResNet:
def __init__(self, depth, stages=4):
self.depth = depth
self.stages = stages
@BACKBONES.register_module()
class ResNeXt:
def __init__(self, depth, stages=4):
self.depth = depth
self.stages = stages
cfg = dict(type='ResNet', depth=50)
model = build_from_cfg(cfg, BACKBONES)
assert isinstance(model, ResNet)
assert model.depth == 50 and model.stages == 4
cfg = dict(type='ResNet', depth=50)
model = build_from_cfg(cfg, BACKBONES, default_args={'stages': 3})
assert isinstance(model, ResNet)
assert model.depth == 50 and model.stages == 3
cfg = dict(type='ResNeXt', depth=50, stages=3)
model = build_from_cfg(cfg, BACKBONES)
assert isinstance(model, ResNeXt)
assert model.depth == 50 and model.stages == 3
cfg = dict(type=ResNet, depth=50)
model = build_from_cfg(cfg, BACKBONES)
assert isinstance(model, ResNet)
assert model.depth == 50 and model.stages == 4
# type defined using default_args
cfg = dict(depth=50)
model = build_from_cfg(
cfg, BACKBONES, default_args=dict(type='ResNet'))
assert isinstance(model, ResNet)
assert model.depth == 50 and model.stages == 4
cfg = dict(depth=50)
model = build_from_cfg(cfg, BACKBONES, default_args=dict(type=ResNet))
assert isinstance(model, ResNet)
assert model.depth == 50 and model.stages == 4
# not a registry
with pytest.raises(TypeError):
cfg = dict(type='VGG')
model = build_from_cfg(cfg, 'BACKBONES')
# non-registered class
with pytest.raises(KeyError):
cfg = dict(type='VGG')
model = build_from_cfg(cfg, BACKBONES)
# default_args must be a dict or None
with pytest.raises(TypeError):
cfg = dict(type='ResNet', depth=50)
model = build_from_cfg(cfg, BACKBONES, default_args=1)
# cfg['type'] should be a str or class
with pytest.raises(TypeError):
cfg = dict(type=1000)
model = build_from_cfg(cfg, BACKBONES)
# cfg should contain the key "type"
with pytest.raises(KeyError, match='must contain the key "type"'):
cfg = dict(depth=50, stages=4)
model = build_from_cfg(cfg, BACKBONES)
# cfg or default_args should contain the key "type"
with pytest.raises(KeyError, match='must contain the key "type"'):
cfg = dict(depth=50)
model = build_from_cfg(
cfg, BACKBONES, default_args=dict(stages=4))
# incorrect registry type
with pytest.raises(TypeError):
cfg = dict(type='ResNet', depth=50)
model = build_from_cfg(cfg, 'BACKBONES')
# incorrect default_args type
with pytest.raises(TypeError):
cfg = dict(type='ResNet', depth=50)
model = build_from_cfg(cfg, BACKBONES, default_args=0)
def build_optimizer_constructor(cfg):
return build_from_cfg(cfg, OPTIMIZER_BUILDERS)