function examp1_5
x=linspace(-0.19050,-0.13824,300); % 選定橫坐標范圍
y=linspace(1.01480,1.06707,300);   % 選定縱坐標范圍
[X,Y]=meshgrid(x,y); n_iter=200; c=0; a=2;
W=mandelbrot(X,Y,c,a,n_iter);  % 調用 Mandelbrot 映射程序
pcolor(X,Y,W), shading flat;
axis('square'); colormap prism(256);
function W=mandelbrot(X,Y,c,a,n_iter) % Mandelbrot 映射程序
C=X+i*Y; W=zeros(size(X)); Z=c;
for k=1:n_iter,
   Z=Z.^2+C;  % 復數映射
   i0=find(abs(Z)>a); W(i0)=k; Z(i0)=NaN;
end
i0=find(W==0); W(i0)=NaN;