On Fri, Nov 16, 2012 at 5:59 PM, Peter B. Kessler <peter.b.kess...@oracle.com> wrote: > What I can't give you is a feeling for how Raul Miller came up with this > particular way of producing that result.
I am not used to seeing my name repeated so many times, I am not sure how to deal with that. That said, I do happen to know how Raul Miller came up with this... so let's see if I can describe that: First, I've used the "modify along one dimension and then transpose with power to modify all dimensions" strategy in other contexts. Also, I am comfortable with #$noun or #@$ as the expression for rank of a noun. So then I was thinking about how transpose was a no-op for a one-dimensional array, and 2 was the number of dimensions here, so I replaced ^:2 with ^:(#@$) and tried the result on some various arrays. After fixing the missing comma, it worked fine on low dimensioned arrays but a $ on a 3d array looked wrong. So, then I remembered that the default definition for |: involved reversing the dimensions or an array, and I wanted to rotate them. So I replaced [: |: with 0 |: and that was the result you saw (the dimension(s) listed in the left argument become the final dimension(s) of the result). So that was all there was to it -- most of the work had already been done. FYI, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
