比较与torch.nn.ConvTranspose3d的差异

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torch.nn.ConvTranspose3d

class torch.nn.ConvTranspose3d(
    in_channels,
    out_channels,
    kernel_size,
    stride=1,
    padding=0,
    output_padding=0,
    groups=1,
    bias=True,
    dilation=1,
    padding_mode='zeros'
)(input) -> Tensor

更多内容详见torch.nn.ConvTranspose3d

mindspore.nn.Conv3dTranspose

class mindspore.nn.Conv3dTranspose(
    in_channels,
    out_channels,
    kernel_size,
    stride=1,
    pad_mode='same',
    padding=0,
    dilation=1,
    group=1,
    output_padding=0,
    has_bias=False,
    weight_init=None,
    bias_init=None,
    data_format='NCDHW'
)(x) -> Tensor

更多内容详见mindspore.nn.Conv3dTranspose

差异对比

PyTorch:计算三维转置卷积,可以视为Conv3d对输入求梯度,也称为反卷积(实际不是真正的反卷积)。输入的shape通常是\((N,C_{in},D_{in},H_{in},W_{in})\),其中\(N\)是batch size,\(C\)是空间维度,\(D_{in},H_{in},W_{in}\)分别为特征层的深度,高度和宽度。输出的shape为\((N,C_{out},D_{out},H_{out},W_{out})\),计算公式如下: \(D_{out}=(D_{in}−1)×stride[0]−2×padding[0]+dilation[0]×(kernel\underline{ }size[0]−1)+output\underline{ }padding[0]+1\) \(H_{out}=(H_{in}−1)×stride[1]−2×padding[1]+dilation[1]×(kernel\underline{ }size[1]−1)+output\underline{ }padding[1]+1\) \(W_{out}=(W_{in}−1)×stride[2]−2×padding[2]+dilation[2]×(kernel\underline{ }size[2]−1)+output\underline{ }padding[2]+1\)

MindSpore:MindSpore此API实现功能与PyTorch基本一致,新增了填充模式参数"pad_mode",当"pad_mode" = "pad"时与PyTorch默认方式相同,利用weight_init 和bias_init 参数可以配置初始化方式。

权重初始化差异

mindspore.nn.Conv3dTranspose的 weight_initNone 时,权重使用HeUniform初始化。此时和PyTorch权重初始化方式一致。

mindspore.nn.Conv3dTranspose的 bias_initNone 时,偏差使用Uniform初始化。此时和PyTorch偏差初始化方式一致。

分类

子类

PyTorch

MindSpore

差异

参数

参数1

in_channels

in_channels

-

参数2

out_channels

out_channels

-

参数3

kernel_size

kernel_size

-

参数4

stride

stride

-

参数5

padding

padding

功能一致,PyTorch中只能在三个维度的两侧分别填充相同的值,可为长度为3的tuple。MindSpore中可以分别设置前部、尾部、顶部、底部、左边和右边的填充数量,可为长度为6的tuple

参数6

output_padding

output_padding

-

参数7

groups

group

功能一致,参数名不同

参数8

bias

has_bias

PyTorch默认为True,MindSpore默认为False

参数9

dilation

dilation

-

参数10

padding_mode

-

数值填充模式,只支持"zeros"即填充0。MindSpore无此参数,但默认填充0

参数11

-

pad_mode

指定填充模式。可选值为"same"、"valid"、"pad",在"same"和"valid"模式下,padding必须设置为0,默认为"same",PyTorch无此参数

参数12

-

weight_init

权重参数的初始化方法。可为Tensor,str,Initializer或numbers.Number。当使用str时,可选"TruncatedNormal","Normal","Uniform","HeUniform"和"XavierUniform"分布以及常量"One"和"Zero"分布的值。默认为None,PyTorch无此参数

参数13

-

bias_init

偏置参数的初始化方法。可选填参数与"weight_init"相同,默认为None,PyTorch无此参数

参数14

-

data_format

数据格式的可选值。目前仅支持"NCDHW",与PyTorch中默认顺序一致,PyTorch无此参数

输入

单输入

input

x

功能一致,参数名不同

代码示例1

两API都是实现三维转置卷积运算,使用时需先进行实例化。为使输出的宽度与输入整除stride后的值相同,PyTorch中设置output_padding = stride - 1,padding设置为(kernel_size - 1)/2。MindSpore则设置pad_mode = "same",同时padding = 0。

# PyTorch
import torch
from torch import tensor
import torch.nn as nn
import numpy as np

k = 5
s = 3
x_ = np.ones([1, 3, 4, 9, 16])
x = tensor(x_, dtype=torch.float32)
net = nn.ConvTranspose3d(3, 32, kernel_size=k, stride=s, padding=(k-1)//2, output_padding=s-1, bias=False)
net.weight.data = torch.ones(3, 32, k, k, k)
output = net(x).detach().numpy()
print(output.shape)
# (1, 32, 12, 27, 48)


# MindSpore
import mindspore as ms
import mindspore.nn as nn
import numpy as np

k = 5
s = 3
x_ = np.ones([1, 3, 4, 9, 16])
x = ms.Tensor(x_, ms.float32)
net = nn.Conv3dTranspose(3, 32, kernel_size=k, stride=s, weight_init='ones', pad_mode='same')
output = net(x)
print(output.shape)
# (1, 32, 12, 27, 48)

代码示例2

两API都是实现三维转置卷积运算,使用时需先进行实例化。若不在原有图像上做任何填充,在stride>1的情况下可能舍弃一部分数据,在PyTorch中将padding和output_padding设为0,MindSpore中设置pad_mode = "valid",同时padding = 0。

# PyTorch
import torch
from torch import tensor
import torch.nn as nn
import numpy as np

k = 5
s = 3
x_ = np.ones([1, 3, 4, 9, 16])
x = tensor(x_, dtype=torch.float32)
net = nn.ConvTranspose3d(3, 32, kernel_size=k, stride=s, bias=False)
net.weight.data = torch.ones(3, 32, k, k, k)
output = net(x).detach().numpy()
print(output.shape)
# (1, 32, 14, 29, 50)


# MindSpore
import mindspore as ms
import mindspore.nn as nn
import numpy as np

k = 5
s = 3
x_ = np.ones([1, 3, 4, 9, 16])
x = ms.Tensor(x_, ms.float32)
net = nn.Conv3dTranspose(3, 32, kernel_size=k, stride=s, weight_init='ones', pad_mode='valid')
output = net(x)
print(output.shape)
# (1, 32, 14, 29, 50)