Easier said than done. On Thu, Oct 14, 2021 at 6:56 AM Hauke Rehr <hauke.r...@uni-jena.de> wrote:
> No, generation is easier. > Take a random permutation along both axes of > |."0 1~ >:i.9 > and then erase numbers as long as they’re derivable > by what remains. > > Am 14.10.21 um 04:19 schrieb Devon McCormick: > > I just put up this page from a past NYCJUG meeting where we talked about > > sudoku - https://code.jsoftware.com/wiki/NYCJUG/2012-11-13#Show-and-Tell > - > > and it only took me ten years! > > Perhaps a harder puzzle is to generate sudoku. > > > > On Wed, Oct 13, 2021 at 7:59 PM Hauke Rehr <hauke.r...@uni-jena.de> > wrote: > > > >> but since N2, N1 and N0 are boxed, > >> you need (N2;N1;<N0) rather than (N2;N1;N0) > >> or, even simpler since they’re already atomic > >> boxes (only one item, empty shape): > >> > >> > is&.>/ (N2,N1,N0) (<@mn@:{)"0 _ g > >> > >> you may even get rid of the "0 _ > >> (but read the vocabulary page for { carfully) > >> > >> > >> Am 14.10.21 um 01:37 schrieb Hauke Rehr: > >>> if I now understand your first question correctly, > >>> you want to learn how to shorten a phrase with > >>> much repetitive structure > >>> > >>> first of all, you can define 'is' this way > >>> is =: e. # [ > >>> > >>> > >>> your expression looks like > >>> (v N2{g) is (v N1{g) is (v N0{g) > >>> with v equal to mn etc. > >>> > >>> if you want to factor out g, you can say > >>> ((N2 v@:{ ]) is (N1 v@:{ ]) is (N0 v@:{ ])) g > >>> > >>> … and if you define > >>> MN =: mn@:{ > >>> you get > >>> ((N2 MN ]) is (N1 MN ]) is (N0 MN ])) g > >>> > >>> if what I wrote for a1, a2 and a3 is correct, > >>> you may then do > >>> > >>> > is&.>/ ((N2 MN ]);(N1 MN ]);(N0 MN ])) g > >>> > >>> which may be further simplified to > >>> > >>> > is&.>/ (N2;N1;N0) (MN&.>)"0 _ g > >>> > >>> and we may substitute back > >>> > >>> > is&.>/ (N2;N1;N0) (mn@:{&.>)"0 _ g > >>> > >>> I hope this works; and maybe someone wants to > >>> comment on different ways to reduce repetitive > >>> expressions. > >>> > >>> > >>> But if your main concern was solving the task > >>> of writing a sudoku solver, take a look at the > >>> wiki page Ric pointed to. > >>> > >>> > >>> Am 14.10.21 um 01:04 schrieb Hauke Rehr: > >>>> Concerning the first question: > >>>> > >>>> try adding ] where g used to be, > >>>> or inserting an & before the { > >>>> (but I didn’t study your code > >>>> enough to /know/ this will work) > >>>> > >>>> 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 > >> > > > > > > -- > ---------------------- > mail written using NEO > neo-layout.org > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA Quantitative Consultant ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
