I notice that we have some components in more than one namespace.
Such as torch::Tensor and at::Tensor, or torch::fft::fft and at::_fft_c2c. In general, it seems we have four namaspaces in Aten.


at;

c10;

caffe2 which is empty; and
torch

Questions

Why do we have four of them?
Does each of them have a different purpose that I am not realizing yet?