Found it. Now the question is whether it solves the same problem. John Gaboury, Letter to the Editor, APL Quote-Quad, Volume 7, Number 4, Winter 1977.
acc=: [ (] * +/\@:%) */\...@] r=. 0.05 0.04 0.06 0.05 0.05 NB. interest rates d=. 1000 0 0 500 0 NB. deposits d acc 1+r 1000 1040 1102.4 1657.52 1740.4 ----- Original Message ----- From: Roger Hui <[email protected]> Date: Saturday, July 18, 2009 9:19 Subject: Re: [Jprogramming] Accumulation, interest, and simulation To: Programming forum <[email protected]> > There was (I think) a very neat solution APL published > in the Quote-Quad in the late 1970s - early 1980s. > It was a very short one-liner involving */\ and +/\ . > I'll see if I can find it or reproduce it. > > Perhaps Joey Tuttle (the keeper of all things) would > have a copy of it. I am pretty sure it would be in > one of the IPSA utility workspaces, such as 880 sauce. > The function would be called "accum" or some such. > > > > ----- Original Message ----- > From: Bill Harris <[email protected]> > Date: Saturday, July 18, 2009 8:20 > Subject: Re: [Jprogramming] Accumulation, interest, and simulation > To: Programming forum <[email protected]> > > > Thanks, all. I figured \. came into it somehow, but I > > didn't get from > > there to the end. I'll study your solutions later today. > > > > Bill > > > > PS: Thanks for not being misled by my typo in the original Aprime > > example, which didn't include the second deposit in the > rolling sum. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
