#304 Julia set using Octave script

Place both files: julia.m and juliatest.m in the same folder:

#{
Calculate a Julia set
zmin = minimum value of c
zmax = maximum value of c
hpx = number of horizontal pixels
niter = Number of iterations
c = complex number
#}
function M = julia(zmin, zmax, hpx, niter, c)
%% Number of vertical pixels
vpx=round(hpx*abs(imag(zmax-zmin)/real(zmax-zmin)));
%% Prepare the complex plane
[zRe,zIm]=meshgrid(linspace(real(zmin),real(zmax),hpx),
linspace(imag(zmin),imag(zmax),vpx));
z=zRe+i*zIm;
M=zeros(vpx,hpx);
%% Generate Julia
for s=1:niter
mask=abs(z)<2;
M(mask)=M(mask)+1;
z(mask)=z(mask).^2+c;
end
M(mask)=0;
end

Jc1=julia(-1.6+1.2i, 1.6-1.2i, 640, 128, -0.75+0.2i);
imagesc(Jc1)
axis off
colormap(turbo)
end