modelx = torch.nn.Sequential(*list(modelx.children())[:-1])

你的第一个问题是关于如何使用 PyTorch 将模型的最后一层移除。你可以使用 `torch.nn.Sequential` 类来构建一个新的模型，然后将原始模型的所有子模块（除了最后一层）添加到新模型中。下面是一个示例代码：

import torch

# 假设原始模型为 modelx
modelx = torch.nn.Sequential(*list(modelx.children())[:-1])

# 现在 modelx 中的最后一层已被移除

使用 `list(modelx.children())[:-1]` 可以获取原始模型的所有子模块（除了最后一层），然后使用 `torch.nn.Sequential` 将这些子模块组合成一个新的模型。

相关问题

如何将self.conv1 = nn.Conv2d(4 * num_filters, num_filters, kernel_size=3, padding=1) self.conv_offset1 = nn.Conv2d(512, 18, kernel_size=3, stride=1, padding=1) init_offset1 = torch.Tensor(np.zeros([18, 512, 3, 3])) self.conv_offset1.weight = torch.nn.Parameter(init_offset1) # 初始化为0 self.conv_mask1 = nn.Conv2d(512, 9, kernel_size=3, stride=1, padding=1) init_mask1 = torch.Tensor(np.zeros([9, 512, 3, 3]) + np.array([0.5])) self.conv_mask1.weight = torch.nn.Parameter(init_mask1) # 初始化为0.5 与torchvision.ops.deform_conv2d，加入到：class NLayerDiscriminator(nn.Module): def init(self, input_nc=3, ndf=64, n_layers=3, norm_layer=nn.BatchNorm2d, use_sigmoid=False, use_parallel=True): super(NLayerDiscriminator, self).init() self.use_parallel = use_parallel if type(norm_layer) == functools.partial: use_bias = norm_layer.func == nn.InstanceNorm2d else: use_bias = norm_layer == nn.InstanceNorm2d kw = 4 padw = int(np.ceil((kw-1)/2)) sequence = [ nn.Conv2d(input_nc, ndf, kernel_size=kw, stride=2, padding=padw), nn.LeakyReLU(0.2, True) ] nf_mult = 1 for n in range(1, n_layers): nf_mult_prev = nf_mult nf_mult = min(2n, 8) sequence += [ nn.Conv2d(ndf * nf_mult_prev, ndf * nf_mult, kernel_size=kw, stride=2, padding=padw, bias=use_bias), norm_layer(ndf * nf_mult), nn.LeakyReLU(0.2, True) ] nf_mult_prev = nf_mult nf_mult = min(2n_layers, 8) sequence += [ nn.Conv2d(ndf * nf_mult_prev, ndf * nf_mult, kernel_size=kw, stride=1, padding=padw, bias=use_bias), norm_layer(ndf * nf_mult), nn.LeakyReLU(0.2, True) ] sequence += [nn.Conv2d(ndf * nf_mult, 1, kernel_size=kw, stride=1, padding=padw)] if use_sigmoid: sequence += [nn.Sigmoid()] self.model = nn.Sequential(*sequence) def forward(self, input): return self.model(input)中，请给出修改后的代码

可以将self.conv1、self.conv_offset1和self.conv_mask1加入到NLayerDiscriminator中的nn.Sequential序列中，如下所示：

import torchvision
from torchvision.ops.deform_conv import DeformConv2d

class NLayerDiscriminator(nn.Module):
    def __init__(self, input_nc=3, ndf=64, n_layers=3, norm_layer=nn.BatchNorm2d, use_sigmoid=False, use_parallel=True):
        super(NLayerDiscriminator, self).__init__()
        self.use_parallel = use_parallel
        if type(norm_layer) == functools.partial:
            use_bias = norm_layer.func == nn.InstanceNorm2d
        else:
            use_bias = norm_layer == nn.InstanceNorm2d
        
        kw = 4
        padw = int(np.ceil((kw-1)/2))
        
        nf_mult = 1
        sequence = [
            nn.Conv2d(input_nc, ndf, kernel_size=kw, stride=2, padding=padw),
            nn.LeakyReLU(0.2, True)
        ]
        
        for n in range(1, n_layers):
            nf_mult_prev = nf_mult
            nf_mult = min(2**n, 8)
            sequence += [
                nn.Conv2d(ndf * nf_mult_prev, ndf * nf_mult, kernel_size=kw, stride=2, padding=padw, bias=use_bias),
                norm_layer(ndf * nf_mult),
                nn.LeakyReLU(0.2, True)
            ]
        
        nf_mult_prev = nf_mult
        nf_mult = min(2**n_layers, 8)
        sequence += [
            DeformConv2d(
                ndf * nf_mult_prev, ndf * nf_mult, kernel_size=3, stride=1, padding=1,
                dilation=1, groups=1, deformable_groups=1, bias=False
            ),
            norm_layer(ndf * nf_mult),
            nn.LeakyReLU(0.2, True),
            nn.Conv2d(ndf * nf_mult, 1, kernel_size=kw, stride=1, padding=padw)
        ]
        
        if use_sigmoid:
            sequence += [nn.Sigmoid()]
        
        self.model = nn.Sequential(*sequence)
        
        self.conv1 = nn.Conv2d(4 * ndf, ndf, kernel_size=3, padding=1)
        self.conv_offset1 = nn.Conv2d(ndf, 18, kernel_size=3, stride=1, padding=1)
        init_offset1 = torch.Tensor(np.zeros([18, ndf, 3, 3]))
        self.conv_offset1.weight = torch.nn.Parameter(init_offset1)
        self.conv_mask1 = nn.Conv2d(ndf, 9, kernel_size=3, stride=1, padding=1)
        init_mask1 = torch.Tensor(np.zeros([9, ndf, 3, 3]) + np.array([0.5]))
        self.conv_mask1.weight = torch.nn.Parameter(init_mask1)
        
    def forward(self, input):
        x = input
        for module in self.model:
            if isinstance(module, DeformConv2d):
                offset_mask = torch.cat([self.conv_offset1(x), self.conv_mask1(x)], dim=1)
                x = module(x, offset_mask)
            else:
                x = module(x)
        return x

这里使用了torchvision.ops.deform_conv2d中的DeformConv2d作为最后一层卷积层，因此需要将self.conv1、self.conv_offset1和self.conv_mask1的通道数修改为ndf。在forward中，对于DeformConv2d层，需要将self.conv_offset1和self.conv_mask1的输出拼接起来作为offset_mask输入。

写出将结构写在一个sequtial中的代码结构与此相同 class CNN(nn.Module): # def __init__(self): # super(CNN, self).__init__() # self.conv1 = nn.Conv2d(3, 32, 3) # self.conv2 = nn.Conv2d(32, 64, 3) # self.conv3 = nn.Conv2d(64, 128, 3) # self.conv4 = nn.Conv2d(128, 256, 3) # self.fc1 = nn.Linear(6400, 1024) # self.fc2 = nn.Linear(1024, 512) # self.fc3 = nn.Linear(512, 128) # self.fc4 = nn.Linear(128, 10) # def forward(self, x): # # 3 x 32 x 32 # x = torch.relu(self.conv1(x)) # 32 x 30 x 30 # x = nn.BatchNorm2d(32).to("cuda")(x) # 32 x 30 x 30 # x = torch.relu(self.conv2(x)) # 64 x 28 x 28 # x = torch.max_pool2d(x, 2) # 64 x 14 x 14 # x = torch.relu(self.conv3(x)) # 128 x 12 x 12 # x = nn.BatchNorm2d(128).to("cuda")(x) # 128 x 12 x 12 # x = torch.relu(self.conv4(x)) # 256 x 10 x 10 # x = torch.max_pool2d(x, 2) # 256 x 5 x 5 # x = x.view(-1, 6400) # x = torch.relu(self.fc1(x)) # x = torch.tanh(self.fc2(x)) # x = torch.relu(self.fc3(x)) # x = self.fc4(x) # return x

以下是将结构写在一个Sequential中的代码：

import torch
import torch.nn as nn

class CNN(nn.Module):
    def __init__(self):
        super(CNN, self).__init__()
        self.model = nn.Sequential(
            nn.Conv2d(3, 32, 3),
            nn.ReLU(),
            nn.BatchNorm2d(32),
            nn.Conv2d(32, 64, 3),
            nn.ReLU(),
            nn.MaxPool2d(2),
            nn.Conv2d(64, 128, 3),
            nn.ReLU(),
            nn.BatchNorm2d(128),
            nn.Conv2d(128, 256, 3),
            nn.ReLU(),
            nn.MaxPool2d(2),
            nn.Flatten(),
            nn.Linear(6400, 1024),
            nn.ReLU(),
            nn.Linear(1024, 512),
            nn.Tanh(),
            nn.Linear(512, 128),
            nn.ReLU(),
            nn.Linear(128, 10)
        )

    def forward(self, x):
        x = self.model(x)
        return x

model = CNN()

在这个代码中，我们使用了`nn.Sequential`来将所有的层组合在一起。每个层都按照从输入到输出的顺序添加到了`nn.Sequential`中。同时，我们也将`nn.BatchNorm2d`和`nn.MaxPool2d`层直接添加到了`nn.Sequential`中。最后，我们在`forward`方法中调用了整个模型。