I haven't tried this in a while but here is one method from an APL book transcribed into J
NB. Magic Squares the APL/J way NB. From APL An Interactive Approach by Gilman and Rose NB. NB. Problem 19 page 177 NB. NB. A magic square of order n made up of the integers from NB. 1 through n. NB. NB. In creating squares of odd order you can use a rotation NB. vector constructed from n successive integers with 0 in NB. the middle then using the vector to control the rotation NB. of the rows and columns of a matrix created with NB. successive integers (in J i. n n) NB. rotr - this uses the rotate operator but sets it to rotate NB. an individual row. Otherwise it will try to rotate NB. the rows in the matrix as a whole interchanging full NB. rows rather than shifting the element in a row and NB. leaving the rows in place rotr =: |."0 1 NB. rotc - rotate the elements in their respective columns. NB. there is no way to tell J to specifically operate on NB. the columns individually so you need to use the NB. transpose op. (|:) to turn the columns into rows by NB. using the &. operator it will transpose, run the rotate NB. then transpose back rotc =: |."0 1&.|: NB. MS - magic square routine no bounds check just input an NB. odd number greater than or equal to 3 MS =: 3 : 0 NB. Create an initial square matrix order n of numbers 1 to n z =. 1 + i. y,y NB. Creat a rotation vector from -n/2 ... 0 ... n/2 q =. ( - (<. 0.5 * y))+ i.y NB. rotate the rows of the matrix my q then rotate the columns NB. of the answer by q. You will get a new matrix that is a NB. magic square z1 =. q rotc q rotr z ) Tom McGuire On Dec 22, 2015, at 9:44 AM, Richard Donovan <rsdono...@hotmail.com> wrote: > Is there a J routine to construct magic squares of side n? > > Thanks in advance. > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
