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

160 lines
4.4 KiB

""" Activations
A collection of activations fn and modules with a common interface so that they can
easily be swapped. All have an `inplace` arg even if not used.
Hacked together by / Copyright 2020 Ross Wightman
"""
import torch
from torch import nn as nn
from torch.nn import functional as F
def swish(x, inplace: bool = False):
"""Swish - Described in: https://arxiv.org/abs/1710.05941
"""
return x.mul_(x.sigmoid()) if inplace else x.mul(x.sigmoid())
class Swish(nn.Module):
def __init__(self, inplace: bool = False):
super(Swish, self).__init__()
self.inplace = inplace
def forward(self, x):
return swish(x, self.inplace)
def mish(x, inplace: bool = False):
"""Mish: A Self Regularized Non-Monotonic Neural Activation Function - https://arxiv.org/abs/1908.08681
NOTE: I don't have a working inplace variant
"""
return x.mul(F.softplus(x).tanh())
class Mish(nn.Module):
"""Mish: A Self Regularized Non-Monotonic Neural Activation Function - https://arxiv.org/abs/1908.08681
"""
def __init__(self, inplace: bool = False):
super(Mish, self).__init__()
def forward(self, x):
return mish(x)
def sigmoid(x, inplace: bool = False):
return x.sigmoid_() if inplace else x.sigmoid()
# PyTorch has this, but not with a consistent inplace argmument interface
class Sigmoid(nn.Module):
def __init__(self, inplace: bool = False):
super(Sigmoid, self).__init__()
self.inplace = inplace
def forward(self, x):
return x.sigmoid_() if self.inplace else x.sigmoid()
def tanh(x, inplace: bool = False):
return x.tanh_() if inplace else x.tanh()
# PyTorch has this, but not with a consistent inplace argmument interface
class Tanh(nn.Module):
def __init__(self, inplace: bool = False):
super(Tanh, self).__init__()
self.inplace = inplace
def forward(self, x):
return x.tanh_() if self.inplace else x.tanh()
def hard_swish(x, inplace: bool = False):
inner = F.relu6(x + 3.).div_(6.)
return x.mul_(inner) if inplace else x.mul(inner)
class HardSwish(nn.Module):
def __init__(self, inplace: bool = False):
super(HardSwish, self).__init__()
self.inplace = inplace
def forward(self, x):
return hard_swish(x, self.inplace)
def hard_sigmoid(x, inplace: bool = False):
if inplace:
return x.add_(3.).clamp_(0., 6.).div_(6.)
else:
return F.relu6(x + 3.) / 6.
class HardSigmoid(nn.Module):
def __init__(self, inplace: bool = False):
super(HardSigmoid, self).__init__()
self.inplace = inplace
def forward(self, x):
return hard_sigmoid(x, self.inplace)
def hard_mish(x, inplace: bool = False):
""" Hard Mish
Experimental, based on notes by Mish author Diganta Misra at
https://github.com/digantamisra98/H-Mish/blob/0da20d4bc58e696b6803f2523c58d3c8a82782d0/README.md
"""
if inplace:
return x.mul_(0.5 * (x + 2).clamp(min=0, max=2))
else:
return 0.5 * x * (x + 2).clamp(min=0, max=2)
class HardMish(nn.Module):
def __init__(self, inplace: bool = False):
super(HardMish, self).__init__()
self.inplace = inplace
def forward(self, x):
return hard_mish(x, self.inplace)
class PReLU(nn.PReLU):
"""Applies PReLU (w/ dummy inplace arg)
"""
def __init__(self, num_parameters: int = 1, init: float = 0.25, inplace: bool = False) -> None:
super(PReLU, self).__init__(num_parameters=num_parameters, init=init)
def forward(self, input: torch.Tensor) -> torch.Tensor:
return F.prelu(input, self.weight)
def gelu(x: torch.Tensor, inplace: bool = False) -> torch.Tensor:
return F.gelu(x)
class GELU(nn.Module):
"""Applies the Gaussian Error Linear Units function (w/ dummy inplace arg)
"""
def __init__(self, inplace: bool = False):
super(GELU, self).__init__()
def forward(self, input: torch.Tensor) -> torch.Tensor:
return F.gelu(input)
def gelu_tanh(x: torch.Tensor, inplace: bool = False) -> torch.Tensor:
return F.gelu(x, approximate='tanh')
class GELUTanh(nn.Module):
"""Applies the Gaussian Error Linear Units function (w/ dummy inplace arg)
"""
def __init__(self, inplace: bool = False):
super(GELUTanh, self).__init__()
def forward(self, input: torch.Tensor) -> torch.Tensor:
return F.gelu(input, approximate='tanh')