www.pudn.com > zishiyingjiami.rar > FDC.m, change:2011-12-27,size:1822b

```%四维混沌序列
function Z=FDC(x_0,y_0,z_0,f_0)
%参数值
a = 50; b = 15; c = 12.4; d = 20; e=0.3
h = 0.01; % 积分时间步长
step1 = 10000;        % 前面的迭代点数
step2 = 5000;         % 后面的迭代点数
X = []; Y = []; Z = []; F = [];
for(i = 1:1:(step1 + step2))
%k1
x_e1 = -a*x_0 + a*y_0+y_0*z_0*f_0 ;
y_e1 = b*x_0 + b*y_0 -x_0*z_0*f_0;
z_e1 = c*(x_0 - z_0)+x_0*y_0*f_0;
f_e1 = e*z_0 - d*f_0+x_0*y_0*z_0 ;
%k2
x_h = x_0 + 0.5*h*x_e1;
y_h = x_0 + 0.5*h*y_e1;
z_h = z_0 + 0.5*h*z_e1;
f_h = f_0 + 0.5*h*f_e1;
x_e2 = -a*x_h + a*y_h+y_h*z_h*f_h;
y_e2 = b*x_h + b*y_h -x_h*z_h*f_h;
z_e2 = c*(x_h - z_h)+x_h*y_h*f_h;
f_e2 = e*z_h - d*f_h+x_h*y_h*z_h ;
%k3
x_h1 = x_0 + 0.5*h*x_e2;
y_h1 = x_0 + 0.5*h*y_e2;
z_h1 = z_0 + 0.5*h*z_e2;
f_h1 = f_0 + 0.5*h*f_e2;
x_e3 = -a*x_h1 + a*y_h1+y_h1*z_h1*f_h1;
y_e3 = b*x_h1 + b*y_h1 -x_h1*z_h1*f_h1;
z_e3 = c*(x_h1 - z_h1)+x_h1*y_h1*f_h1;
f_e3 = e*z_h1 - d*f_h1+x_h1*y_h1*z_h1 ;
%k4
x_h2 = x_0 + h*x_e3;
y_h2 = x_0 + h*y_e3;
z_h2 = z_0 + h*z_e3;
f_h2 = f_0 + h*f_e3;
x_e4 = -a*x_h2 + a*y_h2+y_h2*z_h2*f_h2;
y_e4 = b*x_h2 + b*y_h2 -x_h2*z_h2*f_h2;
z_e4 = c*(x_h2 - z_h2)+x_h2*y_h2*f_h2;
f_e4 = e*z_h2 - d*f_h2+x_h2*y_h2*z_h2 ;

x_1 = x_0 + 1/6*h*(x_e1 + 2*x_e2 +2*x_e3 + x_e4);
y_1 = y_0 + 1/6*h*(y_e1 + 2*y_e2 +2*y_e3 + y_e4);
z_1 = z_0 + 1/6*h*(z_e1 + 2*z_e2 +2*z_e3 + z_e4);
f_1 = f_0 + 1/6*h*(f_e1 + 2*f_e2 +2*f_e3 + f_e4);

X = [X,x_1];
Y = [Y,y_1];
Z = [Z,z_1];
F = [F,f_1];
x_0 = x_1;
y_0 = y_1;
z_0 = z_1;
f_0 = f_1;
end
X = X(step1+1:end);
Y = Y(step1+1:end);
Z = Z(step1+1:end);
F = F(step1+1:end);```