[Scilab-users] Visualising Collatz sequences

[Heinz Nabielek]

Beautiful picture...
Heinz


> On 14.04.2022, at 16:29, Stéphane Mottelet <stephane.mottelet at utc.fr> wrote:
> 
> function X=anglePath3(r, th, ph)
> 
>     
> cumth = cumsum(th);
> 
>     
> cumph = cumsum(ph);
> 
>     
> X = cumsum([0 r.*sin(cumph)
> 
>                 
> 0 r.*sin(cumth).*cos(cumph)
> 
>                 
> 0 r.*cos(cumth).*cos(cumph)], 2);
> end
> 
> 
> 
> function N=collatz(n)
> 
>     
> N = n;
> 
>     
> while n<>1
> 
>         
> if modulo(n,2) == 0
> 
>             
> n = n/2;
> 
>         
> else
> 
>             
> n = 3*n+1;
> 
>         
> end
> 
>         
> N = [n N];
> 
>     
> end
> end
> 
> 
> 
> a=0.1;
> e=1.3;
> 
> 
> 
> clf
> NCOL=512;
> gcf().color_map=parulacolormap(NCOL);
> drawlater
> for i=1:200
> 
>     
> r=collatz(grand(1,1,'uin',1,1000000));
> 
>     
> m1=modulo(r,4);
> 
>     
> m2=m1;
> 
>     
> m1(m1>1)=0;
> 
>     
> m2(m2<=1)=0;
> 
>     
> X=anglePath3(r./(1+r.^e),a*%pi*(0.352-modulo(m1,2)),a*%pi*(0.352-modulo(m2,2)));
> 
>     
> x=rand(3,1)/8;
> 
>     
> param3d(x(1)+X(1,:),x(2)+X(2,:),x(3)+2*X(3,:))
> 
>     
> gce().foreground=min(NCOL,length(r))
> end
> isoview on
> drawnow