In addition to the diagonal expressions in the phrases, http://www.jsoftware.com/docs/help701/phrases/special_matrices.htm is a hook for diagonal.
rank =: #@:$ diagonal =: |:~ <@:i.@:rank diagonal i. 3 3 0 4 8 diagonal i. 3 3 3 0 13 26 diagonal i.3 3 3 3 0 40 80 > Date: Tue, 5 Mar 2013 21:12:02 -0600 > From: "Tom Arneson" <[email protected]> > To: <[email protected]> > Subject: [Jprogramming] extacting the main diagonal of a square matrix > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > I want to create a list containing the main diagonal elements of a square > matrix. Any suggestions? > > Thanks. > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
