Hah, found it. Must have missed it before. Thanks again <J dictionary> x|:y moves axes x to the tail end. If x is boxed, the axes in each box are *run together* to produce a single axis: </J dictionary>
On 6 January 2012 21:10, Alex Giannakopoulos <aeg...@blueyonder.co.uk>wrote: > Thanks, as ever. > > I am off to read up in the dictionary just what that boxed lh argument is > doing. > Anywhere else I should be looking besides the J dictionary? > > > > On 6 January 2012 20:49, Roger Hui <rogerhui.can...@gmail.com> wrote: > >> (<0 1)|:m >> >> >> >> On Fri, Jan 6, 2012 at 12:47 PM, Alex Giannakopoulos < >> aeg...@blueyonder.co.uk> wrote: >> >> > Hi >> > >> > Is there a better (more efficient or whatever) way of getting the >> diagonal >> > of a matrix than the simple multiplication I use below? >> > >> > Say, >> > >> > randmat=. [: ? 0 $~,~ >> > idmat =. [:=i. >> > randiag =. randmat * idmat >> > >> > Many Thanks >> > >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
