mandlebrot-twice-iteration.script

//free parameters are: p1, p2, p3
//return value: f
//iterations count: maxIters

double xn=0,yn=0, xx=0;
double xm=0,ym=0;

double x2=0,y2=0;
int iter = 0;
while (x2+y2<1000 && iter<maxIters){
  
  xx = xm*xm-ym*ym+x;
  ym = 2*xm*ym + y;
  xm = xx;
  
  xx=x2-y2+xm;
  yn=2*xn*yn+ym;
  xn=xx;
  iter=iter+1;
  x2=xn*xn;y2=yn*yn;
}

if (iter >= maxIters){
  f = -1;
}else{
  f = iter-log(log(x2+y2))/log(2);
}