Somehow it feels recursive and a 10 year gap in doing much in J leaves me with a big black hole. I would probably start with a nice little Fibonacci program. This is the kind of question which makes me think "I need a nap".
Hopefully, more later. Linda -----Original Message----- From: programming-boun...@jsoftware.com [mailto:programming-boun...@jsoftware.com] On Behalf Of Kip Murray Sent: Saturday, December 10, 2011 10:07 AM To: Programming forum Subject: Re: [Jprogramming] How #: should have been designed Linda, you may want to look up two's-compliment arithmetic, see http://en.wikipedia.org/wiki/Two's_complement Your idea in hcla is nice. Can you figure out a way to calculate the number of 2's required for the left argument? For example you would need four 2's for (2 2 2 2 hcla i: 5) -: hc i: 5 1 On 12/10/2011 3:56 AM, Linda Alvord wrote: > Kip, Is this what you are looking for: > > > hcla=: 13 :'x#:y' > ]d=:2 2 2 hcla i:2 > 1 1 0 > 1 1 1 > 0 0 0 > 0 0 1 > 0 1 0 > > hcinvla=:hcla^:_1 hcla > hcinvla d > |length error: hcinvla > | hcinvla d > > hcla > #: > hcinvJ=:#:^:_1 > hcinvJ > #:^:_1 > > hcinvJ d > 6 7 0 1 2 > > hcinvla > #. > hcinvla=: 13 :'#.y' > hcinvla d > 6 7 0 1 2 > > Raul's new improved answer hc doesn't appear to deal with the negative > values. My inverse does the best it can with the data it gets. > > My code is mostly from the dictionary. I'm not sure what would be the best > way to deal with negative binary numbers. Maybe I'll remember something > about that a little later. > > Linda > > > -----Original Message----- > From: programming-boun...@jsoftware.com > [mailto:programming-boun...@jsoftware.com] On Behalf Of Kip Murray > Sent: Saturday, December 10, 2011 1:02 AM > To: Programming forum > Subject: Re: [Jprogramming] How #: should have been designed > > Now we need an inverse for Raul's improved #: ("hash colon") > > hc NB. Raul's improved #: > {.@#:@(,: (2 * |)) > > hc i: 2 > 1 1 0 > 1 1 1 > 0 0 0 > 0 0 1 > 0 1 0 > > hcinv NB. improvement sought > 2&#.`(2&#.@}. - 2 ^<:@#)@.{."1 > > hcinv hc i: 2 > _2 _1 0 1 2 > > On 12/8/2011 2:41 PM, Raul Miller wrote: > ... > But this would work just as well, as a model: > > {.@#:@(,: 2 * |)i:2 > 1 1 0 > 1 1 1 > 0 0 0 > 0 0 1 > 0 1 0 > ---------------------------------------------------------------------- > 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
