I’ve found that
mask_ = (box[:, 3] <= box[:, 1]) | (box[:, 2] <= box[:, 0])
works but
mask_ = ( box.select(1, 3) <= box.select(1, 1) ) | ( box.select(1, 2) <= box.select(1, 0) );
does not work…which is quite not understandable for me…
In addition, does libtorch depend on pytorch version? I don’t understand clearly whether libtorch matters with pytorch version because I think libtorch is not connected with pytorch directly.
(Oh, I declare most of variables as torch::Tensor, but when I check the code with vscode, it shows that those are at::Tensor,  which is unexpected for me. Anyway it seems no problem.)