In case you haven't seen it yet: https://code.jsoftware.com/wiki/Essays/Sudoku
On Thu, Oct 14, 2021 at 12:12 PM Hauke Rehr <hauke.r...@uni-jena.de> wrote: > After reading what this is about, > I guess a1, a2 and a3 aren’t atomic > so maybe you want > > is&.>/ a1;a2;a3 > instead > > > Am 14.10.21 um 01:00 schrieb Hauke Rehr: > > Regarding your second question: > > I think it should be > > is/ a1, a2, a3 > > Only literal numbers may be joined into an array by juxtaposition. > > > > Am 14.10.21 um 00:52 schrieb 'Viktor Grigorov' via Programming: > >> Hello, > >> > >> Recently I saw an article in lobste.rs > >> (https://www.hillelwayne.com/post/sudoku/) about sudoku solving, and > >> though t, "it'd be nice to try it J". (Didn't even bother reading it, > >> but later glancing at it found the author had used J in the end. :D) > >> > >> I reshape a list of integers of length 81 with blanks being 0s, > >> row-wise, from top, going left-to-right; into a 4-cube of length 3; > >> and define 3 auxiliary verbs. > >> > >> g=:3 3 3 3 $ ... > >> q=:i.3NB. has missing > >> hm=:0&=@(<./)@, > >> NB. intersection > >> is=:([e.])#[ > >> NB. missing numbers > >> mn=:13 :'((-.((>:@i.9)e.,y))#(>:@i.9))' > >> > >> Although one usually solves sudoku (I think) by thinking of > >> exclusions, as the article's first paragraph or so suggested. I wanted > >> to find symmetries or something similar, thinking of it as a higher > >> dimmensional thing, hence the 4-cube. The constraints, or symmtetries, > >> or whatever they may be are the 9 rows, columns, and faces each > >> containing 1--9 once. My idea is to try each of the 81 cells until > >> once with only one overlap is found, break, then repeat until no change. > >> > >> The sudoku given as an example in the english wikipedia article for > >> sudoku has an 'easy' example, wherein the center of the center > >> resolves to 5 using the intersection of the missing numbers of the 5. > >> row, 5. column, and 5. face; or within the tesseract: > >> > >> (mn(<1;q;1;q){g)is(mn(<1;1;q;q){g)is(mn(<q;q;1;1){g) > >> ((mn(<1;q;1;q)&{)is(...)is(...))g NB. nope > >> > >> Taking out g and binding the from doesn't work, giving me just 1--9. > >> Trying to take out the coordinates doesn't fair well for me either. > >> > >> How can one shorten the former expression using bindings? > >> > >> My second question regards is/: if I define a1, a2, a3 as missing > >> numbers in the row, column, face of some cell, why does is/ a1 a2 a3 > >> give a syntax error, when a1 is a2 is a3 doesn't? > >> > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > >> > > > > -- > ---------------------- > mail written using NEO > neo-layout.org > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
