If it exists, >./([-.-.)/a will find the largest integer common to all of the rows. (If it does not exist, it will give you __ which is the identity element for "largest". In other words, __ >. x always returns x).
To get the smallest replace >. with <. In other words, first find the intersection of all rows, then find the largest (or smallest) number in that intersection. Thanks, -- Raul On Fri, Sep 1, 2017 at 2:48 AM, Skip Cave <s...@caveconsulting.com> wrote: > This wasn't a Quora problem, though I needed to solve this as part of the > solution to a different problem. > > Given the random integer matrix: > > ]a =: 6 12$ ?72$10 > > 2 3 6 6 5 8 3 7 4 9 0 8 > > 1 9 4 1 7 3 1 8 2 5 2 7 > > 4 7 4 7 6 4 1 1 4 6 6 8 > > 5 8 0 0 3 1 8 3 0 7 3 3 > > 4 4 7 3 2 4 7 5 7 3 3 9 > > 3 8 4 1 3 7 8 7 5 6 9 9 > > > What J expression will find the largest integer that is common to all > > of the rows? In this specific case, the answer is 7. > > What about the smallest integer that's common in all rows? > > > Skip > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm