Yes thanks for this. I wasn't especially happy with the existing solution. I agree with Raul that it would be nicer to be consistent with the definition style. I'll try to have a go over the weekend but if it is possible to break either of those long lines up into more recognizable (to non tacit J users) chunks. I think that would be worthwhile.
On Fri, May 11, 2012 at 8:12 AM, Raul Miller <rauldmil...@gmail.com> wrote: > On Thu, May 10, 2012 at 1:46 PM, Aai <agroeneveld...@gmail.com> wrote: >> The J contribution on Rosetta Code >> http://rosettacode.org/wiki/Runge-Kutta_method#J for subject is a loopy >> one. My goal is to change that into a more functional and J-ish one. >> >> Here's my attempt for that particular task: >> >> p4=: 1 :(':';'({:y)+6%~+/1 2 2 1*(x*[: u y+(*x&,@{:))/\.1 0.5 0.5,x*u y') >> >> rk4M=: 1 :0 >> 'Y0 a b h'=. 4{. y >> (,.[:h&(u p4)@(,{:)/\.Y0,~}.)&.|. a+i.@>:&.(%&h) b-a >> ) >> >> (fyp rk4 -: fyp rk4M) 1 0 10 0.001 >> 1 > > As a minor point, I think I would change the definition of p4 > to use the same definition format as rk4M > > p4=: 1 :0 > : > ({:y)+6%~+/1 2 2 1*(x*[: u y+(*x&,@{:))/\.1 0.5 0.5,x*u y > ) > > But I do not have the time to focus on this one. > > I hope I'm not overlooking anything important. > (I wonder if the parenthesized expressions deserve names?) > > Thanks for tackling this! > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
