Sorry, don't think I can do more at this point; I once managed to understand the Shor's algorithm from some book; but I didn't reinforce it, and now I'm left on

Sorry, don't think I can do more at this point; I once managed to understand the Shor's algorithm from some book; but I didn't reinforce it, and now I'm left only with a vague recollection of the main a-ha moment... Though I actually don't really get what do you mean by coherence here (esp. in the area of classical computing).