Okay, My second line is wrong.
>>> sys.getsizeof(net.weight.data)
72

getsizeof can’t handle torch.Tensor
it returns 72 in case of empty tensors also!
So, I did this
>>> t1 = torch.Tensor([5.])
>>> sys.getsizeof(t1.item())
24

Okay, looks good.
But in that case the model will contain
>>> 24 * torch.numel(net.weight.data)
216

I am closer to 4000 bytes! But still far away!
My guess is that each parameter uses far more bytes than its showing up.
I am doing something wrong most likely.