Yes, I did mean +/-.b , thanks. APL on the brain.
On Sun, May 29, 2016 at 4:38 PM, Raul Miller <[email protected]> wrote: > You probably meant (or +/-.b 0s) for your parenthetical comment. > > -- > Raul > > > On Sun, May 29, 2016 at 6:25 PM, Roger Hui <[email protected]> > wrote: > > What you should be looking at are combinations instead of permutations, > > because what you are computing are all the different ways of choosing +/b > > 1s (or +/~b 0s) from i.#b. For example: > > > > b=: 1 1 1 0 0 > > (i.#b) e."1 (+/b) comb #b > > 1 1 1 0 0 > > 1 1 0 1 0 > > 1 1 0 0 1 > > 1 0 1 1 0 > > 1 0 1 0 1 > > 1 0 0 1 1 > > 0 1 1 1 0 > > 0 1 1 0 1 > > 0 1 0 1 1 > > 0 0 1 1 1 > > > > comb is from the for. page of the dictionary. > > http://www.jsoftware.com/help/dictionary/cfor.htm > > > > > > > > On Sun, May 29, 2016 at 2:12 PM, Louis de Forcrand <[email protected]> > wrote: > > > >> Is there a faster (and relatively concise) way of generating > >> (~.@:A.~ i.@!@#) b > >> where b is a logical vector (of 0s and 1s)? > >> There are obviously (+/ ! #) b vectors in the result, but I can't > >> see any relation in their anagram indices: > >> > >> I.@(-:"1/~ ~.)@(A. ~i.@!@#) 1 1 1 0 0 > >> 0 1 6 7 24 25 30 31 48 49 54 55 > >> 2 4 8 10 26 28 32 34 50 52 56 58 > >> 3 5 9 11 27 29 33 35 51 53 57 59 > >> 12 14 18 20 36 38 42 44 60 62 66 68 > >> 13 15 19 21 37 39 43 45 61 63 67 69 > >> 16 17 22 23 40 41 46 47 64 65 70 71 > >> 72 74 78 80 84 86 96 98 102 104 108 110 > >> 73 75 79 81 85 87 97 99 103 105 109 111 > >> 76 77 82 83 88 89 100 101 106 107 112 113 > >> 90 91 92 93 94 95 114 115 116 117 118 119 > >> > >> The (< I , J )&{ of this table corresponds to the Jth occurence > >> of the Ith unique permutation of the vector in its table of all > >> possible permutations. > >> > >> Thanks, > >> Louis > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
