OpenMMLab Detection Toolbox and Benchmark https://mmdetection.readthedocs.io/
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# Copyright (c) OpenMMLab. All rights reserved.
import torch
import torch.nn as nn
import torch.nn.functional as F
from mmcv.cnn import CONV_LAYERS
from .builder import LINEAR_LAYERS
@LINEAR_LAYERS.register_module(name='NormedLinear')
class NormedLinear(nn.Linear):
"""Normalized Linear Layer.
Args:
tempeature (float, optional): Tempeature term. Default to 20.
power (int, optional): Power term. Default to 1.0.
eps (float, optional): The minimal value of divisor to
keep numerical stability. Default to 1e-6.
"""
def __init__(self, *args, tempearture=20, power=1.0, eps=1e-6, **kwargs):
super(NormedLinear, self).__init__(*args, **kwargs)
self.tempearture = tempearture
self.power = power
self.eps = eps
self.init_weights()
def init_weights(self):
nn.init.normal_(self.weight, mean=0, std=0.01)
if self.bias is not None:
nn.init.constant_(self.bias, 0)
def forward(self, x):
weight_ = self.weight / (
self.weight.norm(dim=1, keepdim=True).pow(self.power) + self.eps)
x_ = x / (x.norm(dim=1, keepdim=True).pow(self.power) + self.eps)
x_ = x_ * self.tempearture
return F.linear(x_, weight_, self.bias)
@CONV_LAYERS.register_module(name='NormedConv2d')
class NormedConv2d(nn.Conv2d):
"""Normalized Conv2d Layer.
Args:
tempeature (float, optional): Tempeature term. Default to 20.
power (int, optional): Power term. Default to 1.0.
eps (float, optional): The minimal value of divisor to
keep numerical stability. Default to 1e-6.
norm_over_kernel (bool, optional): Normalize over kernel.
Default to False.
"""
def __init__(self,
*args,
tempearture=20,
power=1.0,
eps=1e-6,
norm_over_kernel=False,
**kwargs):
super(NormedConv2d, self).__init__(*args, **kwargs)
self.tempearture = tempearture
self.power = power
self.norm_over_kernel = norm_over_kernel
self.eps = eps
def forward(self, x):
if not self.norm_over_kernel:
weight_ = self.weight / (
self.weight.norm(dim=1, keepdim=True).pow(self.power) +
self.eps)
else:
weight_ = self.weight / (
self.weight.view(self.weight.size(0), -1).norm(
dim=1, keepdim=True).pow(self.power)[..., None, None] +
self.eps)
x_ = x / (x.norm(dim=1, keepdim=True).pow(self.power) + self.eps)
x_ = x_ * self.tempearture
if hasattr(self, 'conv2d_forward'):
x_ = self.conv2d_forward(x_, weight_)
else:
if torch.__version__ >= '1.8':
x_ = self._conv_forward(x_, weight_, self.bias)
else:
x_ = self._conv_forward(x_, weight_)
return x_