seokju cho
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from itertools import repeat
import collections.abc
from torch import nn as nn
from torchvision.ops.misc import FrozenBatchNorm2d
def freeze_batch_norm_2d(module, module_match={}, name=''):
"""
Converts all `BatchNorm2d` and `SyncBatchNorm` layers of provided module into `FrozenBatchNorm2d`. If `module` is
itself an instance of either `BatchNorm2d` or `SyncBatchNorm`, it is converted into `FrozenBatchNorm2d` and
returned. Otherwise, the module is walked recursively and submodules are converted in place.
Args:
module (torch.nn.Module): Any PyTorch module.
module_match (dict): Dictionary of full module names to freeze (all if empty)
name (str): Full module name (prefix)
Returns:
torch.nn.Module: Resulting module
Inspired by https://github.com/pytorch/pytorch/blob/a5895f85be0f10212791145bfedc0261d364f103/torch/nn/modules/batchnorm.py#L762
"""
res = module
is_match = True
if module_match:
is_match = name in module_match
if is_match and isinstance(module, (nn.modules.batchnorm.BatchNorm2d, nn.modules.batchnorm.SyncBatchNorm)):
res = FrozenBatchNorm2d(module.num_features)
res.num_features = module.num_features
res.affine = module.affine
if module.affine:
res.weight.data = module.weight.data.clone().detach()
res.bias.data = module.bias.data.clone().detach()
res.running_mean.data = module.running_mean.data
res.running_var.data = module.running_var.data
res.eps = module.eps
else:
for child_name, child in module.named_children():
full_child_name = '.'.join([name, child_name]) if name else child_name
new_child = freeze_batch_norm_2d(child, module_match, full_child_name)
if new_child is not child:
res.add_module(child_name, new_child)
return res
# From PyTorch internals
def _ntuple(n):
def parse(x):
if isinstance(x, collections.abc.Iterable):
return x
return tuple(repeat(x, n))
return parse
to_1tuple = _ntuple(1)
to_2tuple = _ntuple(2)
to_3tuple = _ntuple(3)
to_4tuple = _ntuple(4)
to_ntuple = lambda n, x: _ntuple(n)(x)