p=: ?~23 /:p 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22 |.&.>&.C. p 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22
----- Original Message ----- From: Roger Hui <[EMAIL PROTECTED]> Date: Sunday, September 9, 2007 9:06 Subject: Re: [Jprogramming] inverse permutation vector To: Programming forum <[email protected]> > There is an isomorphism between integer permutation vectors > and boolean permutation matrices under {= and i."1&1 . > Therefore: > > (/:p) -: |:&.(({=) :. (i."1&1)) p > > http://www.jsoftware.com/jwiki/Essays/Symmetries_of_the_Square > > > > ----- Original Message ----- > From: Oleg Kobchenko <[EMAIL PROTECTED]> > Date: Sunday, September 9, 2007 0:16 > Subject: Re: [Jprogramming] inverse permutation vector > To: Programming forum <[email protected]> > > > Also > > > > (i. [EMAIL PROTECTED]) p > > 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22 > > > > Variation > > > > [EMAIL PROTECTED]@]`]`]}~ p > > 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22 > > > > > > --- Roger Hui <[EMAIL PROTECTED]> wrote: > > > > > Another solution. Both are well-known in APL circles. > > > > > > ] p=: ?~23 > > > 0 10 12 2 17 13 4 3 8 16 9 6 7 18 15 11 20 21 19 5 1 14 22 > > > /: p > > > 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22 > > > p}~i.#p > > > 0 20 3 7 6 19 11 12 8 10 1 15 2 5 21 14 9 4 13 18 16 17 22 > > > > > > > > > > > > ----- Original Message ----- > > > From: bill lam <[EMAIL PROTECTED]> > > > Date: Saturday, September 8, 2007 20:01 > > > Subject: Re: [Jprogramming] inverse permutation vector > > > To: Programming forum <[email protected]> > > > > > > > Raul Miller wrote: > > > > > ipv=: /: pv > > > > > > > > Thank you, I didn't realize that is so simple. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
