正则化DropPath/drop_path用法示例(Python实现)
DropPath/drop_path 是一种正则化手段,其效果是将深度学习模型中的多分支结构随机”删除“,python中实现如下所示:
def drop_path(x, drop_prob: float = 0., training: bool = False): if drop_prob == 0. or not training: return x keep_prob = 1 - drop_prob shape = (x.shape[0],) + (1,) * (x.ndim - 1) random_tensor = keep_prob + torch.rand(shape, dtype=x.dtype, device=x.device) random_tensor.floor_() # binarize output = x.div(keep_prob) * random_tensor return output class DropPath(nn.Module): def __init__(self, drop_prob=None): super(DropPath, self).__init__() self.drop_prob = drop_prob def forward(self, x): return drop_path(x, self.drop_prob, self.training)
调用如下:
self.drop_path = DropPath(drop_prob) if drop_prob > 0. else nn.Identity() x = x + self.drop_path(self.token_mixer(self.norm1(x))) x = x + self.drop_path(self.mlp(self.norm2(x)))
看起来似乎有点迷茫,这怎么就随机删除了分支呢
实验如下:
import torch drop_prob = 0.2 keep_prob = 1 - drop_prob x = torch.randn(4, 3, 2, 2) shape = (x.shape[0],) + (1,) * (x.ndim - 1) random_tensor = keep_prob + torch.rand(shape, dtype=x.dtype, device=x.device) random_tensor.floor_() output = x.div(keep_prob) * random_tensor
输出:
x.size():[4,3,2,2]
x:
tensor([[[[ 1.3833, -0.3703],
[-0.4608, 0.6955]],
[[ 0.8306, 0.6882],
[ 2.2375, 1.6158]],
[[-0.7108, 1.0498],
[ 0.6783, 1.5673]]],[[[-0.0258, -1.7539],
[-2.0789, -0.9648]],
[[ 0.8598, 0.9351],
[-0.3405, 0.0070]],
[[ 0.3069, -1.5878],
[-1.1333, -0.5932]]],[[[ 1.0379, 0.6277],
[ 0.0153, -0.4764]],
[[ 1.0115, -0.0271],
[ 1.6610, -0.2410]],
[[ 0.0681, -2.0821],
[ 0.6137, 0.1157]]],[[[ 0.5350, -2.8424],
[ 0.6648, -1.6652]],
[[ 0.0122, 0.3389],
[-1.1071, -0.6179]],
[[-0.1843, -1.3026],
[-0.3247, 0.3710]]]])
random_tensor.size():[4, 1, 1, 1] random_tensor: tensor([[[[0.]]], [[[1.]]], [[[1.]]], [[[1.]]]])
output.size():[4,3,2,2] output: tensor([[[[ 0.0000, -0.0000], [-0.0000, 0.0000]], [[ 0.0000, 0.0000], [ 0.0000, 0.0000]], [[-0.0000, 0.0000], [ 0.0000, 0.0000]]], [[[-0.0322, -2.1924], [-2.5986, -1.2060]], [[ 1.0748, 1.1689], [-0.4256, 0.0088]], [[ 0.3836, -1.9848], [-1.4166, -0.7415]]], [[[ 1.2974, 0.7846], [ 0.0192, -0.5955]], [[ 1.2644, -0.0339], [ 2.0762, -0.3012]], [[ 0.0851, -2.6027], [ 0.7671, 0.1446]]], [[[ 0.6687, -3.5530], [ 0.8310, -2.0815]], [[ 0.0152, 0.4236], [-1.3839, -0.7723]], [[-0.2303, -1.6282], [-0.4059, 0.4638]]]])
random_tensor作为是否保留分支的直接置0项,若drop_path的概率设为0.2,random_tensor中的数有0.2的概率为0,而output中被保留概率为0.8。
结合drop_path的调用,若x为输入的张量,其通道为[B,C,H,W],那么drop_path的含义为在一个Batch_size中,随机有drop_prob的样本,不经过主干,而直接由分支进行恒等映射。
总结
到此这篇关于正则化DropPath/drop_path用法(Python实现)的文章就介绍到这了,更多相关正则化DropPath/drop_path内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!
相关文章
Django import export实现数据库导入导出方式
这篇文章主要介绍了Django import export实现数据库导入导出方式,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧2020-04-04Python图像锐化与边缘检测之Scharr,Canny,LOG算子详解
图像锐化和边缘检测主要包括一阶微分锐化和二阶微分锐化,本文主要讲解常见的图像锐化和边缘检测方法,即Scharr算子、Canny算子和LOG算子,需要的可以参考一下2022-12-12
最新评论