comet3a.m

来自「王小平《遗传算法——理论、应用与软件实现》随书光盘」· M 代码 · 共 52 行

function comet3(x,y,z,p)

if nargin == 0,
   z = -pi:pi/500:pi;
   y = cos(3*z);
   x = sin(5*z);
   p = 0.1;
else
  if nargin < 3, z = x; x = 1:length(z); y = 1:length(z); end
  if nargin < 4, p = 0.10; end
end

%clf
%axis([min(x(finite(x))) max(x(finite(x))) min(y(finite(y)))  ...
%      max(y(finite(y))) min(z(finite(z))) max(z(finite(z)))])

% Cyan circle head, yellow line body, and magenta line tail.
head = line('color','c','linestyle','o','erase','xor','xdata',x(1),'ydata',y(1), ...
       'zdata',z(1));
body = line('color','b','linestyle','-','erase','none','xdata',[],'ydata',[], ...
       'zdata',[]);
tail = line('color',[0 0 0],'linestyle','-','erase','none','xdata',[],'ydata',[], ...
       'zdata',[]);

m = length(z);
k = round(p*m);

% Grow the body
for i = 2:k+1
   j = i-1:i;
   set(head,'xdata',x(i),'ydata',y(i),'zdata',z(i))
   set(body,'xdata',x(j),'ydata',y(j),'zdata',z(j))
   drawnow
end

% Primary loop
m = length(x);
for i = k+2:m
   j = i-1:i;
   set(head,'xdata',x(i),'ydata',y(i),'zdata',z(i))
   set(body,'xdata',x(j),'ydata',y(j),'zdata',z(j))
   set(tail,'xdata',x(j-k),'ydata',y(j-k),'zdata',z(j-k))
   drawnow
end

% Clean up the tail
for i = m+1:m+k
   j = i-1:i;
   set(tail,'xdata',x(j-k),'ydata',y(j-k),'zdata',z(j-k))
   drawnow
end