spirale.m

用matlab实现利用统计混沌方法解决非线性系统时间序列预测的问题

function out = spirale(nbr,revo,step)
% The function
% 
%       out = spirale(nbr,revo,step);
% 
% generates a 2-dimensional database with <nbr> elements. 
% These elements draw a spiral. 
% The optional parameter <revo> gives the number of 
% revolution of the spiral; default value is 2.0. 
% The optional parameter <step> sets the distance between 
% two "consecutive spires"; default value is 1.0.  

if nargin<2, revo = 2; end;
if nargin<3, step = 1; end;

r = rand([nbr,1]);

out = zeros([nbr,2]);

out(:,1) = step*revo*r.*cos(2*pi*revo*r);
out(:,2) = step*revo*r.*sin(2*pi*revo*r);