In practice log* (at least for base 2) can have only a very few values, so something involving I. should work quite well.
On Mon, Jul 7, 2014 at 7:19 AM, Dan Bron <[email protected]> wrote: > Iterated log, usually written as log*(n), is defined piecewise as: > > +--------------------- > / 0 if n<:1 > log*(n)= > \ 1+log*(log n) if n> 1 > +--------------------- > > This can be expressed directly in J using agenda (@.): > > logstar =: 0:`(1+$:@^.)@.(1<:])"0 > > But this feels fairly "procedural". All the work is in the recursion. Is > there a more elegant way to express it? > > -Dan > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
