runtime error : invalid argument 0: Sizes of tensors must match except in dimension 1

I have a PyTorch model and I’m trying to test it by performing a forward pass with random data. Here is the code:

class ResBlock(nn.Module):
    def __init__(self, inplanes, planes, stride=1):
        super(ResBlock, self).__init__()
        self.conv1x1 = nn.Conv2d(inplanes, planes, kernel_size=1, stride=1, bias=False)
        self.conv1 = nn.Conv2d(inplanes, planes, kernel_size=3, stride=stride, padding=1, bias=False)
        #batch normalization
        self.bn1 = nn.BatchNorm2d(planes)
        self.relu = nn.ReLU()
        self.conv2 = nn.Conv2d(planes, planes, kernel_size=3, stride=stride, padding=1, bias=False)
        self.bn2 = nn.BatchNorm2d(planes)
        self.stride = stride

    def forward(self, x):
        residual = self.conv1x1(x)

        out = self.conv1(x)
        out = self.bn1(out)
        out = self.relu(out)

        out = self.conv2(out)
        out = self.bn2(out)
        
        #adding the skip connection
        out += residual
        out = self.relu(out)

        return out

class ResUnet (nn.Module):

    def __init__(self, in_shape,  num_classes):
        super(ResUnet, self).__init__()
        in_channels, height, width = in_shape
        #
        #self.L1 = IncResBlock(in_channels,64)
        self.e1 = nn.Sequential(
            nn.Conv2d(in_channels, 64, kernel_size=4, stride=2,padding=1),
            ResBlock(64,64))
            
        
        self.e2 = nn.Sequential(
            nn.LeakyReLU(0.2,),
            nn.Conv2d(64, 128, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(128),
            ResBlock(128,128))
        #
        self.e2add = nn.Sequential(
            nn.Conv2d(128, 128, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(128))
        #
        ##
        self.e3 = nn.Sequential(
            nn.LeakyReLU(0.2,inplace=True),
            nn.Conv2d(128, 128, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(128),
            nn.LeakyReLU(0.2,),
            nn.Conv2d(128,256, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(256),
            ResBlock(256,256))
    
        self.e4 = nn.Sequential(
            nn.LeakyReLU(0.2,),
            nn.Conv2d(256,512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            ResBlock(512,512))
        #
        self.e4add = nn.Sequential(
            nn.Conv2d(512,512, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(512)) 
        #
        self.e5 = nn.Sequential(
            nn.LeakyReLU(0.2,inplace=True),
            nn.Conv2d(512,512, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(512),
            nn.LeakyReLU(0.2,),
            nn.Conv2d(512,512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            ResBlock(512,512))
        #
        #
        self.e6 = nn.Sequential(
            nn.LeakyReLU(0.2,),
            nn.Conv2d(512,512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512), 
            ResBlock(512,512))
        #
        self.e6add = nn.Sequential(
            nn.Conv2d(512,512, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(512)) 
        #
        self.e7 = nn.Sequential(
            nn.LeakyReLU(0.2,inplace=True),
            nn.Conv2d(512,512, kernel_size=3, stride=1,padding=1),
            nn.BatchNorm2d(512),
            nn.LeakyReLU(0.2,),
            nn.Conv2d(512,512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            ResBlock(512,512))
        #
        self.e8 = nn.Sequential(
            nn.LeakyReLU(0.2,),
            nn.Conv2d(512,512, kernel_size=4, stride=2,padding=1))
            #nn.BatchNorm2d(512))

        self.d1 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(512, 512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            nn.Dropout(p=0.5),
            ResBlock(512,512))
        #
        self.d2 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(1024, 512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            nn.Dropout(p=0.5),
            ResBlock(512,512))
        #
        self.d3 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(1024, 512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            nn.Dropout(p=0.5),
            ResBlock(512,512))
        #
        self.d4 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(1024, 512, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(512),
            ResBlock(512,512))

        #
        self.d5 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(1024, 256, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(256),
            ResBlock(256,256))
        #
        self.d6 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(512, 128, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(128),
            ResBlock(128,128))
        #
        self.d7 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(256, 64, kernel_size=4, stride=2,padding=1),
            nn.BatchNorm2d(64),
            ResBlock(64,64))
        #
        self.d8 = nn.Sequential(
            nn.ReLU(),
            nn.ConvTranspose2d(128, 64, kernel_size=4, stride=2,padding=1))
            #nn.BatchNorm2d(64),
            #nn.ReLU())

        self.out_l = nn.Sequential(
            nn.Conv2d(64,num_classes,kernel_size=1,stride=1))
            #nn.ReLU())
   
    def forward(self, x):

        #Image Encoder

        #### Encoder #####

        en1 = self.e1(x)

        en2 = self.e2(en1)
        en2add = self.e2add(en2)

        en3 = self.e3(en2add)

        en4 = self.e4(en3)
        en4add = self.e4add(en4)

        en5 = self.e5(en4add)

        en6 = self.e6(en5)
        en6add = self.e6add(en6)

        en7 = self.e7(en6add)

        en8 = self.e8(en7)

        #### Decoder ####
        de1_ = self.d1(en8)
        de1 = torch.cat([en7,de1_],1)

        de2_ = self.d2(de1)
        de2 = torch.cat([en6add,de2_],1)
        
        
        de3_ = self.d3(de2)
        de3 = torch.cat([en5,de3_],1)

        
        de4_ = self.d4(de3)
        de4 = torch.cat([en4add,de4_],1)
        
        
        de5_ = self.d5(de4)
        de5 = torch.cat([en3,de5_],1)
        
        de6_ = self.d6(de5)
        de6 = torch.cat([en2add,de6_],1)
    
        de7_ = self.d7(de6)
        de7 = torch.cat([en1,de7_],1)
        de8 = self.d8(de7)

        out_l_mask = self.out_l(de8)
         
        return out_l_mask  

Here is how I attempt to test it:

modl = ResUnet((1,512,512), 1)
x = torch.rand(1, 1, 512, 512)
modl(x)

This works fine, as does for any size that are multiples of 64.

If I try:

modl = ResUnet((1,320,320), 1)
x = torch.rand(1, 1, 320, 320)
modl(x)

It throws an error

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-46-4ddc821c365b> in <module>
----> 1 modl(x)

~/.conda/envs/torch0.4/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
    475             result = self._slow_forward(*input, **kwargs)
    476         else:
--> 477             result = self.forward(*input, **kwargs)
    478         for hook in self._forward_hooks.values():
    479             hook_result = hook(self, input, result)

<ipython-input-36-f9eeefa3c0b8> in forward(self, x)
    221         de2_ = self.d2(de1)
    222         #print de2_.size()
--> 223         de2 = torch.cat([en6add,de2_],1)
    224         #print de2.size()
    225 

RuntimeError: invalid argument 0: Sizes of tensors must match except in dimension 1. Got 5 and 4 in dimension 2 at /opt/conda/conda-bld/pytorch_1535491974311/work/aten/src/TH/generic/THTensorMath.cpp:3616

I figure the problem is caused by the input size not being a power of 2 but I am not sure how to rectify it for the given input dimenstions (320, 320).

If you would like to use different resolutions, you might add an adaptive pooling layer before the torch.cat call, so that the output will always be resized to your desired shape.

1 Like

Got it, thanks a lot for this.