ts 'p i. i.#p' 0.00602786 1.57363e6 Compared to: > ts '/:p' > 0.00611782 1.04922e6 > ts '(i.#p) p}p' > 0.0112338 1.57389e6
p i. i.#p is also known in APL but seldom used to compute /:p because it's slower than (i.#p) p}p ----- Original Message ----- From: Zsbán Ambrus <[EMAIL PROTECTED]> Date: Wednesday, November 5, 2008 15:35 Subject: Re: [Jprogramming] cut on length To: Programming forum <[email protected]> > On Thu, Nov 6, 2008 at 00:17, Roger Hui <[EMAIL PROTECTED]> wrote: > > Re: The implementation should reward conciseness. > > > > In APL it was (and is) well-known that the inverse of > > a permutation p can be computed as (i.#p) p}p > > and is more efficient than /:p . But watch this: > > How does (p i.(i.#p)) compare to these? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
