Thanks, The Gaboury note seems to ring a bell. I will look at the finance addon as well.
On Sat, Nov 28, 2015 at 2:50 PM, chris burke <[email protected]> wrote: > To add payments at interest rates, you should first discount or accumulate > the payments to a single point in time, then add them up, then reverse the > first step. You need to take care whether payments are in advance or > arrears. > > e.g. the following discounts payments to time 0: > > p=. 100 200 300 > > i=. 0.05 0.06 0.07 > > > acc=. */\1+i > > acc * +/\p % 1,}:acc > > 105 323.3 666.931 > > See also the finance/interest addon. > > On 28 November 2015 at 12:27, John Baker <[email protected]> wrote: > > > A nasty combination of too much recent programming in loopy languages > > combined with advancing age has dulled my memory of how to properly grow > a > > rate adjusted series without looping. The following solves my immediate > > problem but my sense of J aesthetics is appalled. > > > > Would anyone care to provide a more J'ey solution. > > > > AccumulateSeries2=:4 : 0 > > > > > > NB.*AccumulateSeries2 v-- accumulate rate adjusted current and > > > > NB. future series credits and charges. > > > > NB. > > > > NB. dyad: nl =. ia AccumulateSeries2 ntSeriesGrowth > > > > NB. > > > > NB. sr=. ((5#100),0 0 _80 0 0 200 200) ,: (6#1),6$1.001667 0.98 1 > > > > NB. (3 AccumulateSeries2 sr) ,: 0{sr > > > > > > 'sv gr'=. y > > > > > > NB. forward last actuals and accumulate rate adjusted > > > > pv=. x {. sv > > > > cv=. (_1 {. pv) , x }. sv > > > > cg=. (_1 {. x {. gr) , x }. gr > > > > > > for_j. i.<:#cv do. > > > > cv=. (((>:j){cv) + (j{cg) * j{cv) (>:j)} cv > > > > end. > > > > > > pv , }. cv > > > > ) > > > > > > -- > > John D. Baker > > [email protected] > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- John D. Baker [email protected] ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
