Error in loading state_dict for customed model
I had problems when loading the weights of model. Here's some parts of the model

class InceptionV4(nn.Module):

   def __init__(self, num_classes=1001):
       super(InceptionV4, self).__init__()
       # Special attributs
       self.input_space = None
       self.input_size = (299, 299, 3)
       self.mean = None
       self.std = None
       # Modules
       self.features = nn.Sequential(
           BasicConv2d(3, 32, kernel_size=3, stride=2),
           BasicConv2d(32, 32, kernel_size=3, stride=1),
           BasicConv2d(32, 64, kernel_size=3, stride=1, padding=1),
           Mixed_3a(),
           Mixed_4a(),
           Mixed_5a(),
           Inception_A(),
           Inception_A(),
           Inception_A(),
           ...
       )
       self.avg_pool = nn.AvgPool2d(8, count_include_pad=False)
       self.last_linear = nn.Linear(1536, num_classes)


I have tried to save the weights, something like torch.save(model.state_dict(), weight_name) and then reload again model.load_state_dict(torch.load(weight_name))
but got these errors:

Missing key(s) in state_dict: "features.0.conv.weight", "features.0.bn.weight", "features.0.bn.bias", "features.0.bn.running_mean", "features.0.bn.running_var", "features.1.conv.weight", "features.1.bn.weight", "features.1.bn.bias", "features.1.bn.running_mean", "features.1.bn.running_var", "features.2.conv.weight", "features.2.bn.weight


and also:

Unexpected key(s) in state_dict: "conv.0.conv1.0.weight", "conv.0.conv1.0.bias", "conv.0.conv1.2.weight", "conv.0.conv1.2.bias", "conv.0.conv1.2.running_mean", "conv.0.conv1.2.running_var", "conv.0.conv1.2.num_batches_tracked", "conv.0.conv2.0.weight", "conv.0.conv2.0.bias", "conv.0.conv2.2.weight", "conv.0.conv2.2.bias", "conv.0.conv2.2.running_mean", "conv.0.conv2.2.running_var", "conv.0.conv2.2.num_batches_tracked", "conv.1.conv1.0.weight", "conv.1.conv1.0.bias", "conv.1.conv1.2.weight", "conv.1.conv1.2.bias", "conv.1.conv1.2.running_mean", "conv.1.conv1.2.running_var", "conv.1.conv1.2.num_batches_tracked


Any hints on this? Thanks in advance.

I faced this problem several times. The error indicates that your model state_dict has different names from the pre-trained weights that you load.

I don't see the pretrained model for Inception_v4 in torchvision model zoo, so it would be a little difficult to tell exactly where your InceptionV4 class has a problem with mismatched dict.

Regardless of where you get your the pre-trained file, but the key point is to define your model the same as the pre-trained model code, and you can load the weight file smoothly.

Here are some indicators where your code is different from the model:


# change self.features -&gt; self.conv: This helps in solving mismatched names.

self.conv = nn.Sequential(...)


# Google how to change the BatchNorm in your current pytorch version 
# and  the older pytorch version which the pretrained model was defined.

conv.1.conv1.2.num_batches_tracked  # it is deprecated in pytorch version 0.4 or newer


The hint is:


# Define your model (or parts you want to reuse) the same as the original 



Hope this helps :)
