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pytorch-image-models/timm/models/layers/norm_act.py

87 lines
3.5 KiB

""" Normalization + Activation Layers
"""
import torch
from torch import nn as nn
from torch.nn import functional as F
from .create_act import get_act_layer
class BatchNormAct2d(nn.BatchNorm2d):
"""BatchNorm + Activation
This module performs BatchNorm + Activation in a manner that will remain backwards
compatible with weights trained with separate bn, act. This is why we inherit from BN
instead of composing it as a .bn member.
"""
def __init__(self, num_features, eps=1e-5, momentum=0.1, affine=True, track_running_stats=True,
apply_act=True, act_layer=nn.ReLU, inplace=True, drop_block=None):
super(BatchNormAct2d, self).__init__(
num_features, eps=eps, momentum=momentum, affine=affine, track_running_stats=track_running_stats)
if isinstance(act_layer, str):
act_layer = get_act_layer(act_layer)
if act_layer is not None and apply_act:
act_args = dict(inplace=True) if inplace else {}
self.act = act_layer(**act_args)
else:
self.act = None
def _forward_jit(self, x):
""" A cut & paste of the contents of the PyTorch BatchNorm2d forward function
"""
# exponential_average_factor is self.momentum set to
# (when it is available) only so that if gets updated
# in ONNX graph when this node is exported to ONNX.
if self.momentum is None:
exponential_average_factor = 0.0
else:
exponential_average_factor = self.momentum
if self.training and self.track_running_stats:
# TODO: if statement only here to tell the jit to skip emitting this when it is None
if self.num_batches_tracked is not None:
self.num_batches_tracked += 1
if self.momentum is None: # use cumulative moving average
exponential_average_factor = 1.0 / float(self.num_batches_tracked)
else: # use exponential moving average
exponential_average_factor = self.momentum
x = F.batch_norm(
x, self.running_mean, self.running_var, self.weight, self.bias,
self.training or not self.track_running_stats,
exponential_average_factor, self.eps)
return x
@torch.jit.ignore
def _forward_python(self, x):
return super(BatchNormAct2d, self).forward(x)
def forward(self, x):
# FIXME cannot call parent forward() and maintain jit.script compatibility?
if torch.jit.is_scripting():
x = self._forward_jit(x)
else:
x = self._forward_python(x)
if self.act is not None:
x = self.act(x)
return x
class GroupNormAct(nn.GroupNorm):
# NOTE num_channel and num_groups order flipped for easier layer swaps / binding of fixed args
def __init__(self, num_channels, num_groups, eps=1e-5, affine=True,
apply_act=True, act_layer=nn.ReLU, inplace=True, drop_block=None):
super(GroupNormAct, self).__init__(num_groups, num_channels, eps=eps, affine=affine)
if isinstance(act_layer, str):
act_layer = get_act_layer(act_layer)
if act_layer is not None and apply_act:
self.act = act_layer(inplace=inplace)
else:
self.act = None
def forward(self, x):
x = F.group_norm(x, self.num_groups, self.weight, self.bias, self.eps)
if self.act is not None:
x = self.act(x)
return x