My pleasure Mark, thanks for the feedback. I find that in the process of answering questions like this, I help solidify my own understanding so I'm glad we were both able to benefit!! Ric
> From: Mark Allen > > Ric, > > As another relatively neophyte J-er, I must applaud your exposition in > that > it really cleared up for me how +/ worked over square matrices. I had > always > in my mind when working on problems thought of +/"1 as 'going across > the > rows', and +/"2 as 'going down the columns', which of course worked, > and of > course I in some sense knew (as a mantra almost) that '+/"1 inserts + > between each rank 1 item of the noun it is applied to', but your > explanation and example is clear enough to both make intuitive sense > and be > technically accurate. Thank you :) > > > On 29 April 2010 22:47, Sherlock, Ric wrote: > > > > From: Robert O'Boyle > > > > > > I have come across a feature of J that I didn't expect. When I add > > > rows of a matrix, I use +/"1 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm