Yes, well, left as an exercise for the reader. :-) Idea: the minimum rotation of a vector necessarily begins with its minimal item.
On Wed, Feb 13, 2019 at 9:34 AM Henry Rich <[email protected]> wrote: > Yes; but now suppose the lines are very long. Is there a way to find > the signature (I would call it a canonical form) that doesn't require > enumerating rotations? (I haven't found a good way yet). > > Henry Rich > > On 2/13/2019 12:16 PM, Roger Hui wrote: > > For each row, find a "signature", then find the nub sieve of the > > signatures. The signature I use here is the minimum of all possible > > rotations. > > > > signature=: {. @ (/:~) @ (i.@# |."0 1 ]) > > > > ~: signature"1 a > > 1 1 1 1 1 0 1 1 1 1 1 0 > > > > > > > > > > On Wed, Feb 13, 2019 at 8:55 AM R.E. Boss <[email protected]> wrote: > > > >> Let the 12 x 20 matrix be defined by > >> a=: 0 : 0 > >> 1 4 4 1 _4 _4 1 1 _4 _1 _1 _4 _4 _1 4 4 _1 _1 4 1 > >> 1 4 4 1 _4 _4 1 1 _4 _1 _1 _4 _4 _1 4 1 4 _1 _1 4 > >> 1 4 4 1 _4 _1 _4 1 1 _4 _1 _4 _4 _1 4 1 4 _1 _1 4 > >> 4 1 1 4 _1 4 1 _4 _4 1 _4 _1 _1 _4 1 _4 _1 4 4 _1 > >> 4 1 1 4 _1 4 1 _4 _4 1 1 _4 _1 _1 _4 _4 _1 4 4 _1 > >> _1 4 1 1 4 4 1 _4 _4 1 1 _4 _1 _1 _4 _4 _1 4 4 _1 > >> _1 4 4 _1 _4 _4 _1 _1 _4 1 1 _4 _4 1 4 4 1 1 4 _1 > >> _1 4 4 _1 _4 _4 _1 _1 _4 1 1 _4 _4 1 4 _1 4 1 1 4 > >> _1 4 4 _1 _4 1 _4 _1 _1 _4 1 _4 _4 1 4 _1 4 1 1 4 > >> 4 _1 _1 4 1 4 _1 _4 _4 _1 _4 1 1 _4 _1 _4 1 4 4 1 > >> 4 _1 _1 4 1 4 _1 _4 _4 _1 _1 _4 1 1 _4 _4 1 4 4 1 > >> 1 4 _1 _1 4 4 _1 _4 _4 _1 _1 _4 1 1 _4 _4 1 4 4 1 > >> ) > >> > >> Required is the nubsieve for the items modulo rotation. > >> So two arrays are considered to be equal if one is a rotation of the > other. > >> > >> The answer I found is > >> 1 1 1 1 1 0 1 1 1 1 1 0 > >> > >> > >> R.E. Boss > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > --- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
