I’m afraid it is not   It will be once NestedTensor 5 is merged though 
If you want to make sure not to do any extra copy, I would advise not to use advanced indexing (like data[i, j, :]) and only use the .select() and .narrow() methods. If you only use these two methods, you are 100% sure you’re not doing any copy. You will see that if you cannot use these methods to do what you want, it usually means that you have to copy