Dear senior programmers,

I am a beginner both with Pytorch and programming. I have managed to use the following codes of a VNet model to train my data. However, the obtained results are not satisfactory. I would like to insert other layers such as dense block or residual block. Please, could you provide me with some lines of code or repository that could help me achieve that?

The VNet codes are as follows

```
class ConvBlock(nn.Module):
def __init__(self, n_stages, n_filters_in, n_filters_out, normalization='none'):
super(ConvBlock, self).__init__()
ops = []
for i in range(n_stages):
if i==0:
input_channel = n_filters_in
else:
input_channel = n_filters_out
ops.append(nn.Conv3d(input_channel, n_filters_out, 3, padding=1))
if normalization == 'batchnorm':
ops.append(nn.BatchNorm3d(n_filters_out))
elif normalization == 'groupnorm':
ops.append(nn.GroupNorm(num_groups=16, num_channels=n_filters_out))
elif normalization == 'instancenorm':
ops.append(nn.InstanceNorm3d(n_filters_out))
elif normalization != 'none':
assert False
ops.append(nn.LeakyReLU(0.2,inplace=True))
self.conv = nn.Sequential(*ops)
def forward(self, x):
x = self.conv(x)
return x
class DownsamplingConvBlock(nn.Module):
def __init__(self, n_filters_in, n_filters_out, stride=2, normalization='none'):
super(DownsamplingConvBlock, self).__init__()
ops = []
if normalization != 'none':
ops.append(nn.Conv3d(n_filters_in, n_filters_out, stride, padding=0, stride=stride))
if normalization == 'batchnorm':
ops.append(nn.BatchNorm3d(n_filters_out))
elif normalization == 'groupnorm':
ops.append(nn.GroupNorm(num_groups=16, num_channels=n_filters_out))
elif normalization == 'instancenorm':
ops.append(nn.InstanceNorm3d(n_filters_out))
else:
assert False
else:
ops.append(nn.Conv3d(n_filters_in, n_filters_out, stride, padding=0, stride=stride))
ops.append(nn.LeakyReLU(0.2, inplace=True))
self.conv = nn.Sequential(*ops)
def forward(self, x):
x = self.conv(x)
return x
class UpsamplingDeconvBlock(nn.Module):
def __init__(self, n_filters_in, n_filters_out, stride=2, normalization='none'):
super(UpsamplingDeconvBlock, self).__init__()
ops = []
if normalization != 'none':
ops.append(nn.ConvTranspose3d(n_filters_in, n_filters_out, stride, padding=0, stride=stride))
if normalization == 'batchnorm':
ops.append(nn.BatchNorm3d(n_filters_out))
elif normalization == 'groupnorm':
ops.append(nn.GroupNorm(num_groups=16, num_channels=n_filters_out))
elif normalization == 'instancenorm':
ops.append(nn.InstanceNorm3d(n_filters_out))
else:
assert False
else:
ops.append(nn.ConvTranspose3d(n_filters_in, n_filters_out, stride, padding=0, stride=stride))
ops.append(nn.LeakyReLU(0.2, inplace=True))
self.conv = nn.Sequential(*ops)
def forward(self, x):
x = self.conv(x)
return x
class VNet(nn.Module):
def __init__(self, n_channels=3, n_classes=2, n_filters=16, normalization='none', has_dropout=False):
super(VNet, self).__init__()
self.has_dropout = has_dropout
self.block_one = ConvBlock(1, n_channels, n_filters, normalization=normalization)
self.block_one_dw = DownsamplingConvBlock(n_filters, 2 * n_filters, normalization=normalization)
self.block_two = ConvBlock(2, n_filters * 2, n_filters * 2, normalization=normalization)
self.block_two_dw = DownsamplingConvBlock(n_filters * 2, n_filters * 4, normalization=normalization)
self.block_three = ConvBlock(3, n_filters * 4, n_filters * 4, normalization=normalization)
self.block_three_dw = DownsamplingConvBlock(n_filters * 4, n_filters * 8, normalization=normalization)
self.block_four = ConvBlock(3, n_filters * 8, n_filters * 8, normalization=normalization)
self.block_four_dw = DownsamplingConvBlock(n_filters * 8, n_filters * 16, normalization=normalization)
self.block_five = ConvBlock(3, n_filters * 16, n_filters * 16, normalization=normalization)
self.block_five_up = UpsamplingDeconvBlock(n_filters * 16, n_filters * 8, normalization=normalization)
self.block_six = ConvBlock(3, n_filters * 8, n_filters * 8, normalization=normalization)
self.block_six_up = UpsamplingDeconvBlock(n_filters * 8, n_filters * 4, normalization=normalization)
self.block_seven = ConvBlock(3, n_filters * 4, n_filters * 4, normalization=normalization)
self.block_seven_up = UpsamplingDeconvBlock(n_filters * 4, n_filters * 2, normalization=normalization)
self.block_eight = ConvBlock(2, n_filters * 2, n_filters * 2, normalization=normalization)
self.block_eight_up = UpsamplingDeconvBlock(n_filters * 2, n_filters, normalization=normalization)
self.block_nine = ConvBlock(1, n_filters, n_filters, normalization=normalization)
self.out_conv = nn.Conv3d(n_filters, n_classes, 1, padding=0)
self.dropout = nn.Dropout3d(p=0.5, inplace=False)
self.sigmoid = nn.Sigmoid()
# self.__init_weight()
def encoder(self, input):
x1 = self.block_one(input)
x1_dw = self.block_one_dw(x1)
x2 = self.block_two(x1_dw)
x2_dw = self.block_two_dw(x2)
x3 = self.block_three(x2_dw)
x3_dw = self.block_three_dw(x3)
x4 = self.block_four(x3_dw)
x4_dw = self.block_four_dw(x4)
x5 = self.block_five(x4_dw)
# x5 = F.dropout3d(x5, p=0.5, training=True)
if self.has_dropout:
x5 = self.dropout(x5)
res = [x1, x2, x3, x4, x5]
return res
def decoder(self, features):
x1 = features[0]
x2 = features[1]
x3 = features[2]
x4 = features[3]
x5 = features[4]
x5_up = self.block_five_up(x5)
x5_up = x5_up + x4
x6 = self.block_six(x5_up)
x6_up = self.block_six_up(x6)
x6_up = x6_up + x3
x7 = self.block_seven(x6_up)
x7_up = self.block_seven_up(x7)
x7_up = x7_up + x2
x8 = self.block_eight(x7_up)
x8_up = self.block_eight_up(x8)
x8_up = x8_up + x1
x9 = self.block_nine(x8_up)
# x9 = F.dropout3d(x9, p=0.5, training=True)
if self.has_dropout:
x9 = self.dropout(x9)
out = self.out_conv(x9)
#out = self.sigmoid(out)
return out
def forward(self, input, turnoff_drop=False):
if turnoff_drop:
has_dropout = self.has_dropout
self.has_dropout = False
features = self.encoder(input)
out = self.decoder(features)
if turnoff_drop:
self.has_dropout = has_dropout
return out
```

Any suggestions or comments would be highly appreciated