i.3 3 3 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25 26 (<0 1 2)|:i.3 3 3 0 13 26 (<0 1)|:i.3 3 3 0 12 24 1 13 25 2 14 26 2012/1/7 "Papp Erik Tamás" <papp.e...@ybl.szie.hu> > Hi, > > Some example of getting the main diagonal of square matrices: > > ]A=:2 2$1 2 3 4 > 1 2 > 3 4 > > (<0 1)|:A NB. The main diagonal of a square matrix A > 1 4 > > ]B=:3 3$1 2 3 4 5 6 > 1 2 3 > 4 5 6 > 1 2 3 > > (<0 1)|:B NB. The main diagonal of a square matrix B > 1 5 3 > > ]N=:4 4$i. 16 > 0 1 2 3 > 4 5 6 7 > 8 9 10 11 > 12 13 14 15 > > (<0 1)|:N NB. The main diagonal of a square matrix N > 0 5 10 15 > > Regards, > > Erik > ----- Eredeti levél (Original Message) ----- > Feladó: Alex Giannakopoulos <aeg...@blueyonder.co.uk> > Dátum: Péntek, Január 6, 2012 9:48 du > Tárgy: [Jprogramming] Getting the diagonal of a square matrix > Címzett: Programming forum <programming@jsoftware.com> > > > Hi > > > > Is there a better (more efficient or whatever) way of getting > > the diagonal > > of a matrix than the simple multiplication I use below? > > > > Say, > > > > randmat=. [: ? 0 $~,~ > > idmat =. [:=i. > > randiag =. randmat * idmat > > > > Many Thanks > > ----------------------------------------------------------------- > > ----- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
