Hi Simone & Cedric, Thanks for your comment. In fact, my purpose is to demonstrate to my colleagues how Clojure deals with this algorithm. I'm going to implement the Brent's way.
However, I'm wondering if I can make the Floyd's more functional. Tail recursion is good, but not good enough to show the "paradigm shift" (of functional programming) to my colleagues. Any ideas? Thanks! :) 2013年6月30日日曜日 2時58分57秒 UTC+8 Cedric Greevey: > > If the function is expensive to compute, you might prefer Brent's > periodicity detection algorithm, which instead of 1.5xn invocations of the > function only requires n + o(log n) invocations and supposedly detects just > as fast. > > You store [last-n, last-f, next-n] = [0, f(0), 1] and then, for n = 1 to > whatever: > > * compute f(n) > * see if it's equal to last-f; if it is, f is or becomes periodic with a > period dividing n - last-n. > * if n = next-n, change the store to [n, f(n), 2*next-n] > * move on to f(n + 1). > > > > On Sat, Jun 29, 2013 at 10:43 AM, Simone Mosciatti > <mweb...@gmail.com<javascript:> > > wrote: > >> It is very interesting, just a friendly suggestion, if you share code, >> and need some help, make sure people can get immediately what is going on. >> (READ: comment the code) >> >> >> On Saturday, June 29, 2013 1:34:57 PM UTC+2, Zhemin Lin wrote: >>> >>> Hi. >>> One of my colleagues gave a share about the cycle detecting >>> tortoise-hare algorithm >>> (wiki<http://en.wikipedia.org/wiki/Cycle_detection#Tortoise_and_hare> >>> ). >>> I translated the script on Wiki from Python to Clojure. >>> It worked, but not elegant. I'd like to make it more functional, more >>> tasty. >>> Any suggestions to help it evolve? >>> >>> I uploaded my (messy) code here: https://github.com/** >>> miaoski/clojure-tortoise-hare<https://github.com/miaoski/clojure-tortoise-hare> >>> Thanks a lot! :) >>> >>> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
