Sorry, but not on my computer: Nx2 =: i.600000 2x df1=:+ 6!:2 'z=:df1/ |:Nx2' 0.46775 6!:2 'z=:df1/"1 Nx2' 1.18481
I was thinking in the first case it does df1 only once (on a lot of data), and in the second case many times, element by element. Greetings, Ben ________________________________________ From: [email protected] [[email protected]] on behalf of David Lambert [[email protected]] Sent: Wednesday, April 30, 2014 12:48 To: [email protected] Subject: Re: [Jprogramming] Applying a dyad to exusting matrix data Time to learn about rank! In my experience u"1 N_BY_2_MATRIX runs faster than u@:|: N_BY_2_MATRIX > Date: Wed, 30 Apr 2014 10:49:40 +0100 > From: alexgian<[email protected]> > To: J Programming forum<[email protected]> > Subject: [Jprogramming] Applying a dyad to exusting matrix data > Message-ID: > <CAD=r9jom2p_mnztgruxw4_teevqzu2hwaxfi9hzrfmwfc7p...@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Suppose I have an Nx2 data matrix, say > x1 y1 > x2 y2 > x3 y3 > .... > and a dyadic verb called, say, df1 > > > Is there an elegant way to get the result matrix > x1 df1 y1 > x2 df1 y2 > x3 df1 y3 > ..... > > without resorting to "from - {" and "take - {." jiggery-pokery > Or perhaps just a means to convert an expresiion from the > df1 x1 y1 form, to > x1 df1 y1 > > All suggestions gratefully received. > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
