On 17 Jul, 22:43, Isaac Hodes <iho...@mac.com> wrote: > It's just a shame, it seems to me, that there is such a nice way to > represent the procedure in Python or even C, yet Clojure (or any Lisp > really) struggles to idiomatically answer this question of > convolution.
I'll have to disagree with the conclusion. I agree that there are many algorithms that can be elegantly expressed as iteration over mutable arrays, but in any Lisp with arrays (including at least Clojure and Common Lisp) you can use those algorithms in Lisp just as much as you can in Python or C. I can't really see that it is less idiomatic to use arrays in Lisp than in C when it suits the problem. The only difference I can tell between David Nolen's version and the C, Python or DSP Guide algorithm is that Clojure has a more verbose syntax for accessing arrays - the logic, flow and operations are exactly the same. (And you don't need to initialize the result array to 0.) Philosophically, I think it's mostly a matter of the set of 'cheap' vs 'expensive' operations being different in imperative and functional code, so for a well-performing functional version you normally need a different algorithm, which can be a non-trivial task to discover. But you did get a couple of nice looking and decently performing functional versions among the responses. Practically, I go for imperative algorithms most of the time since I can copy them pretty much verbatim from the literature and don't need to spend hours on each of them trying to find an efficient functional formulation. Plus of course that the imperative versions are faster. I'm writing a fair amount of this kind of code, and I'm using Clojure since the number crunching can be an order of magnitude faster than Python or Ruby (for my purposes Python is simply too slow, while imperative and type-hinted Clojure is fast enough), and Clojure is much nicer to use than Java or C. But certainly, if you need numeric performance over everything C or Fortran would be the language of choice. jf -- 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
