How to produce 4-dimensional input for 4-dimensional weight?
I am very new to Deep learning. I am working on the CIFAR10 dataset and created a CNN model which is as below.
class Net2(nn.Module):
  def __init__(self):
    super(Net2, self).__init__()
    self.conv1 = nn.Conv2d(3, 32, 5, 1)
    self.fc1 = nn.Linear(32 * 5 * 5, 512)
    self.fc2 = nn.Linear(512,10)


  def forward(self, x):
    x = x.view(x.size(0), -1)
    x = F.max_pool2d(F.relu(self.conv1(x)),(2,2))
    x = F.relu(self.fc1(x))
    x = self.fc2(x)
    return x
    

net2 = Net2().to(device)

My assignment requirements are to create a model with:
Convolutional layer with 32 filters, kernel size of 5x5 and stride of 1.
Max Pooling layer with kernel size of 2x2 and default stride.
ReLU Activation Layers.
Linear layer with output of 512.
ReLU Activation Layers.
A linear layer with output of 10.
Which I guess I wrote. But I am assuming that I am going to the wrong path. Please help me to write the correct model and also the reason behind those arguments in Conv2d and Linear layers.
The error which I am getting from my code is as below:
RuntimeError: Expected 4-dimensional input for 4-dimensional weight [32, 3, 5, 5], but got 2-dimensional input of size [1024, 3072] instead

Please help me!

There are two problems with the code:

Flattening of input
x = x.view(x.size(0), -1)

The convolutional layer expects a four dimensional input of dimensions (N, C, H, W), where N is the batch size, C = 3 is the number of channels, and (H, W) is the dimension of the image. By using the above statement, you are flattening your (1024, 3, 32, 32) input to (1024, 3072).

Number of input features in the first linear layer
self.fc1 = nn.Linear(32 * 5 * 5, 512)

The output dimensions of the convolutional layer for a (1024, 3, 32, 32) input will be (1024, 32, 28, 28), and after applying the 2 x 2 maxpooling, it is (1024, 32, 14, 14). So the number of input features for the linear layer should be 32 x 14 x 14 = 6272.


