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Ztanzbulb(QUATERNION) {
parameter real bailout;
parameter int steps;
real pixelr,pixeli,pixelj;
real x1,x2,y1,y2,z1,z2,rho1,rho2,A,B,C;
quaternion res, res1,c;
int m;

quaternion inv(quaternion q)
{
	q = q-quaternion(0,2*part_i(q),0,0);
	q = q/|q|;
	return(q);
}

quaternion mult(quaternion q, quaternion p)
{
	x1 = part_r(q);
	y1 = part_i(q);
	z1 = part_j(q);
	rho1 = sqrt(x1*x1+y1*y1);
	
	x2 = part_r(p);
	y2 = part_i(p);
	z2 = part_j(p);
	rho2 = sqrt(x2*x2+y2*y2);
	
	if (rho1 == 0){
		p =(z1*p);
	} else if (rho2 == 0){
		p = z2*p;
	} else{
		A = (x1*x2-y1*y2)*(z1/rho1+z2/rho2);
		B = (x1*y2+x2*y1)*(z1/rho1+z2/rho2);
		C = (rho1*rho2-z1*z2);
		p = (quaternion(A,B,C,0));
	}
	return(p);
}
quaternion div(quaternion q, quaternion p)
{
	x1 = part_r(q);
	y1 = part_i(q);
	z1 = part_j(q);
	rho1 = sqrt(x1*x1+y1*y1);
	
	x2 = part_r(p);
	y2 = part_i(p);
	z2 = part_j(p);
	rho2 = sqrt(x2*x2+y2*y2);
	
	if (rho1 == 0){
		p =inv(p)*z1;
	} else if (rho2 == 0){
		p = p/z2;
	} else{
		A = (x1*x2+y1*y2)*(z1/rho1-z2/rho2)/|p|;
		B = (x1*y2-x2*y1)*(z1/rho1-z2/rho2)/|p|;
		C = (rho1*rho2+z1*z2)/|p|;
		p = (quaternion(A,B,C,0));
	}
	return(p);
}

quaternion tangent(quaternion q)
{
	res = 0.0;
	for (m = steps+1; m>1; m=m-1){
		res1 = mult(z,z)*(-1.0/(2*m-3)/(2*m-1));
		res = div(res1,res+quaternion(0,0,1,0));
	}
	return(div(z,res+quaternion(0,0,1,0)));
}

	void init(void)
	{
		pixelr=part_r(pixel);
		pixeli=part_i(pixel);
		pixelj=part_j(pixel);
		c=quaternion(pixelr,pixeli,pixelj,0);
		z=c;
	}
	void loop(void)
	{
		z=mult(z,tangent(z))+c;
	}
	bool bailout(void)
	{
		return(|z|<bailout);
	}

	void description(void)
	{
		this.title = "ztanzbulb";

		bailout.caption = "Bailout Value";
		bailout.default = 4.0;
		bailout.min = 1.0;
		bailout.hint = "Defines the bailout radius: As soon as a pixel falls outside a circle with this radius, the iteration stops.";
		
		steps.caption = "Steps";
		steps.default = 2;
		steps.min = 1;
		steps.hint = "Controls how deep into the continued fraction the tangent function goes.";
		
	}
}