Yes that is correct; u"n M always divides up into cells formed by grouping the last n dimensions together. Another way to see it is that elements of the array M who have the same (#$M) - n first indices are grouped together.
A variant on u"n M is "(-n), which is roughly equivalent to u"((#$M)-n) M. If you need to break M up according to axes which are not on the tail end, you can look into |: transpose. Cheers, Louis > On 28 Feb 2018, at 07:18, Nick S <[email protected]> wrote: > > Someone please tell me if I understand this: > > If I have a list of 5x5 tables, that is, a thing with a shape of n 5 5 > where n is anything from 1 to 30, That is, the shape of the table might be > (5 5 or 2 5 5 or 3 5 5 etc.) and I want to compare it against a single 5x5 > thing in 5x5 groups, the proper rank to use for the comparison is 2, as > > a ="2 b or a -:"2 b or a *."2 b > > depending on what I want to do. > > When I use a rank 2, does it take the last two dimensions of whatever and > use those? The examples I see are all for the more common cases of taking > a table and processing it by individual items, rows or columns. My > experimentation seems to indicate that my guess is true, but I am so damned > confused at this point, I need to see if I am on the right track. > > -- > Of course I can ride in the carpool lane, officer. Jesus is my constant > companion. > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
