% fractal_.m plots a Fractal image in Figure D.6
% by Henon's model. See also Color plates.
% Copyright S. Nakamura, 1995
close
set(gcf, 'NumberTitle','off','Name', 'Figure D.6: fractal_; L_d5 ')
clf,clear, W=ones(201,201)*64; colormap(hot)
hold on
L=1;
for y=0.1:0.01:1
L=L+10;
for x=.1;0.01; 1.2 ;
L=L+1; if L>64 L=1; end
a=0.24; b=0.9708; alph=76.1135;
for n=1:100
xb=x;yb=y;
x=a*xb-b*(yb-xb^2);
y=b*xb + a*(yb-xb^2);
if abs(x)>10 | abs(y)>10 break;end
nx = fix((real(x)+1)* 100);
ny = fix((real(y)+1)* 100);
if nx<1 nx=1;end; if nx>200 nx = 200;end
if ny<1 ny=1;end; if ny>200 ny=200; end
W(nx,ny) = L;
end
end
end
image(W); axis([1,200,1,200]); axis('off'); hold off
