The infinite sum looks OK to me. http://en.wikipedia.org/wiki/Blancmange_curve
----- Original Message ----- From: Henry Rich <[email protected]> Date: Sunday, August 28, 2011 8:01 Subject: Re: [Jprogramming] a new question To: Programming forum <[email protected]> > With infinite rank: > > tent =: -:@:(|&.(0.5&-)) > tent _0.1 0 0.1 0.2 0.3 0.5 0.7 0.8 0.9 1 1.1 > _0.05 0 0.05 0.1 0.15 0.25 0.15 0.1 0.05 0 _0.05 > > I got nothin' on the infinite sum (which looks to me like it has > a typo > in the spec) > > Henry Rich > > On 8/28/2011 10:38 AM, Marshall Lochbaum wrote: > > How about > > > > tent=: 0>. [:-: -.^:(>&0.5)"0 > > tent _0.1 0 0.1 0.2 0.3 0.5 0.7 0.8 > 0.9 1 1.1 > > 0 0 0.05 0.1 0.15 0.25 0.15 0.1 0.05 0 0 > > > > Marshall > > > > On Sun, Aug 28, 2011 at 7:47 AM, Ric > Sherlock<[email protected]> wrote: > > > >> Here's one tacit approach to the tent function: > >> tent=: 0:`-:`(-:@-.)`0:@.(0 0.5 1&I.)"0 > >> tent _0.1 0 0.1 0.2 0.3 0.5 0.7 0.8 0.9 1 1.1 > >> 0 0 0.05 0.1 0.15 0.25 0.15 0.1 0.05 0 0 > >> > >> Given it is rank 0 I expect its performance can be improved. Also > >> although dyadic I. appears to work in this case, it doesn't > strictly>> follow the 0<=x condition below. > >> > >> On Sun, Aug 28, 2011 at 10:40 PM, mikel > paternain<[email protected]>>> wrote: > >>> > >>> How do you write in J a "tent" function: > >>> > >>> g(x)= > x/2 if 0<=x<=1/2, > >>> > (1-x)/2 if 1/2< x< 1 > >>> > >>> and, more important, How do you write in J a Takagi function > with the > >> "tent" function: > >>> > >>> h(x)= Sum [r=0 to infinite, g(2^r x)/2^r] ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
