Actually, it IS a (4D binary reflected) Gray code.
R.E. Boss (Add your info to http://www.jsoftware.com/jwiki/Community/Demographics ) > -----Original Message----- > From: [email protected] [mailto:programming- > [email protected]] On Behalf Of Devon McCormick > Sent: vrijdag 15 november 2013 19:33 > To: J-programming forum > Subject: Re: [Jprogramming] Sets > > These look like Gray codes. > > On Nov 14, 2013 10:04 PM, "Raul Miller" <[email protected]> wrote: > > > > Easy enough to add. > > > > It's an interesting progression though: > > > > #:/:&> (<@#~ 2 #:@i.@^ #)&.> set 2;'b';1;'a' > > 0 0 0 0 > > 1 0 0 0 > > 1 1 0 0 > > 1 1 1 0 > > 1 1 1 1 > > 1 1 0 1 > > 1 0 1 0 > > 1 0 1 1 > > 1 0 0 1 > > 0 1 0 0 > > 0 1 1 0 > > 0 1 1 1 > > 0 1 0 1 > > 0 0 1 0 > > 0 0 1 1 > > 0 0 0 1 > > > > -- > > Raul > > > > On Thu, Nov 14, 2013 at 6:06 PM, km <[email protected]> wrote: > > > Cool; needs a sort. --Kip > > > > > > > > > psr=: (<@#~ 2 #:@i.@^ #)&.> NB. Raul's > > > psr set 0;1 > > > +----------------+ > > > |++---+---+-----+| > > > |||+-+|+-+|+-+-+|| > > > ||||1|||0|||0|1||| > > > |||+-+|+-+|+-+-+|| > > > |++---+---+-----+| > > > +----------------+ > > > ps set 0;1 NB. list inside box is sorted > > > +----------------+ > > > |++---+-----+---+| > > > |||+-+|+-+-+|+-+|| > > > ||||0|||0|1|||1||| > > > |||+-+|+-+-+|+-+|| > > > |++---+-----+---+| > > > +----------------+ > > > > > > Sent from my iPad > > > > > >> On Nov 14, 2013, at 3:17 PM, Raul Miller <[email protected]> > wrote: > > >> > > >> Derived from ps at http://rosettacode.org/wiki/Power_set#J > > >> > > >> ps=: (<@#~ 2 #:@i.@^ #)&.> > > >> > > >> -- > > >> Raul > > >> > > >> > > >>> On Thu, Nov 14, 2013 at 3:17 PM, km <[email protected]> wrote: > > >>> Here is my latest attempt at sets in J. Would anyone care to write a > verb ps (power set) such that ps y is the set of all subsets of set y? > It's called the power set in part because when a set has n elements its > power set has 2^n elements. --Kip Murray > > >>> > > >>> NB. A set is a box with a sorted list of boxes inside. > > >>> NB. An element is the contents of a box in the list. > > >>> NB. A -: B tests whether set A is set B. > > >>> > > >>> set =: [: < [: /:~ ~. NB. create set from list of boxes > > >>> > > >>> NB. The list may have duplicates but the set has none. > > >>> > > >>> EE =: <$0 NB. empty set, same as Ace a: > > >>> > > >>> eo =: <@[ e. >@] NB. test whether x is an element of y > > >>> > > >>> uu =: [: set ,&> NB. union > > >>> > > >>> mm =: [: < -.&> NB. minus > > >>> > > >>> sd =: mm uu mm~ NB. symmetric difference > > >>> > > >>> cp =: uu mm sd NB. common part (intersection) > > >>> > > >>> ss =: uu -: ] NB. test whether x is a subset of y > > >>> > > >>> (set 1;2;3;3) -: set 3;1;2 > > >>> 1 > > >>> > > >>> ]A =: set 2;'b';1;'a' > > >>> +---------+ > > >>> |+-+-+-+-+| > > >>> ||1|2|a|b|| > > >>> |+-+-+-+-+| > > >>> +---------+ > > >>> > > >>> ]B =: set 'b';'a';4;3;'a' > > >>> +---------+ > > >>> |+-+-+-+-+| > > >>> ||3|4|a|b|| > > >>> |+-+-+-+-+| > > >>> +---------+ > > >>> > > >>> A uu B > > >>> +-------------+ > > >>> |+-+-+-+-+-+-+| > > >>> ||1|2|3|4|a|b|| > > >>> |+-+-+-+-+-+-+| > > >>> +-------------+ > > >>> > > >>> A sd B > > >>> +---------+ > > >>> |+-+-+-+-+| > > >>> ||1|2|3|4|| > > >>> |+-+-+-+-+| > > >>> +---------+ > > >>> > > >>> A cp B > > >>> +-----+ > > >>> |+-+-+| > > >>> ||a|b|| > > >>> |+-+-+| > > >>> +-----+ > > >>> > > >>> NB. Below is the set of all subsets of set 0;1 > > >>> > > >>> set EE;(set <0);(set <1);<set 0;1 > > >>> +------------------------+ > > >>> |+--+-----+-------+-----+| > > >>> ||++|+---+|+-----+|+---+|| > > >>> ||||||+-+|||+-+-+|||+-+||| > > >>> ||++|||0|||||0|1|||||1|||| > > >>> || ||+-+|||+-+-+|||+-+||| > > >>> || |+---+|+-----+|+---+|| > > >>> |+--+-----+-------+-----+| > > >>> +------------------------+ > > >>> > > >>> Sent from my iPad > > >>> ---------------------------------------------------------------------- > > >>> 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 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
