Comment by benjamin-lee

You hit the nail on the head. This is just the lexicographically minimal string rotation with a canonicalization step. I have actually had this on my to-do list for a while. The truth is that the data set I'm applying this to is small (though I'm doing my best to change that by discovering new viroid-like agents) so the optimization has yet to become pressing. At some point, I'd like to spin this script out into a standalone tool but I'm not sure the demand is there yet.