POV-Ray : Newsgroups : povray.advanced-users : 3D Mandelbrot set : Re: 3D Mandelbrot set Server Time
30 Jul 2024 14:28:36 EDT (-0400)
  Re: 3D Mandelbrot set  
From: Peter Popov
Date: 3 Nov 1999 16:09:41
Message: <A6IgOHjCsBvrQd3Al38R9V6WoZRz@4ax.com>
On 3 Nov 1999 11:00:24 -0500, Nieminen Juha
<war### [at] punarastascstutfi> wrote:

>Peter Popov <pet### [at] usanet> wrote:
>: #declare Rn = (R*R-I*I)+X;
>: #declare In = (2*R*I-J*J)+Y;
>: #declare Jn= (2*J*I+2*J*R)+Z;
>
>  Where does this formula come from? Is the formula for Jn just a randomly
>chosen one?
>  What's the bailout value?

According to Mark he came up with it. it more of a hack than anything
else, but it sure works darn good. Now here's the snippet of code from
Mark's program that does the iteration:

iter = 0;
r = X; i = Y; j = Z;
while(iter < maxiter && ((r*r)+(i+i)+(j*j)) <= 4)
{
	rn = ((r*r)-(i*i))+X;
	in = ((2*r*i)-(j*j))+Y;
	j  = ((2*i*j)+(2*r*j))+Z;
	r  = rn;
	i  = in;
	iter++;
}

So you see the bailout is 4, as usual (but you can always change it or
leave it to the user)




Peter Popov
ICQ: 15002700


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