Hi, maybe you could flatten the tensors and concat them? Use
flatten1 = tensor11.view(1, -1) and torch.cat(flatten1, flatten2, flatten3)
Would it work if you’d just calculate the 3 losses separately and then add them?
mse = nn.MSELoss()
loss1 = mse(tensor1l, tensor12)
loss2 = mse(tensor2l, tensor22)
loss3 = mse(tensor3l, tensor32)
total_loss = loss1 + loss2 + loss3
# backpropagate