POV-Ray : Newsgroups : povray.text.tutorials : Summing over indices of an array : Re: Summing over indices of an array Server Time
26 Sep 2021 21:09:38 EDT (-0400)
  Re: Summing over indices of an array  
From: moocow
Date: 2 Jan 2006 20:05:00
Message: <web.43b9cd3b4b45696074508c90@news.povray.org>
Christoph Hormann <chr### [at] gmxde> wrote:
> Mike Williams wrote:
> >
> > I think you have to use a loop:
> >
>
> Bah, you surely don't have to:
>
> #macro Add(i)
>    #if (i>0)
>      #local R=Add(i-1)+elem[i];
>    #else
>      #local R=elem[i];
>    #end
>    R
> #end
>
> #declare Sum=Add(n);
>
> ;-)
>
> Christoph
>
> --
> POV-Ray tutorials, include files, Sim-POV,
> HCR-Edit and more: http://www.tu-bs.de/~y0013390/
> Last updated 23 Sep. 2004 _____.//^>_*_<^/.______

What if I want to define a function as a sum of other functions?

#declare X = array[N]
//set X's

#declare f = function{ sum(i, 0, N-1, pow(.5, pow( vlength(<x,y,z> - X[i]),
2))) }

I can't think of how to make that work.

Also, why these restrictions? Why can't I sum outside a function or use
arrays inside? Why can't I do:
#define f1 = function { f1(x,y,z) + g(x,y,z) }
?


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