Hey @glooty, welcome to the community.
I agree with the need for a code sample from your side to fully understand what are you trying to do and what is the math behind providing you an answer, but we haven't heard from you in a while, so I'm closing this thread.
Feel free to re-open another one if you still have the same question since I think it'd be an interesting learning exercise to be posted here in the forum, but please follow these guidelines for asking questions.