danbai.m

这是关于非线性单摆的混沌解法后期出现的庞加莱图的matlab程序

clc; 
kk=20; 
NN=64; 
c1=0.5;c3=2/3; 
t=2*pi/c3; 
c2=.98;n=1; 
Fun1=inline('y2','x','y2'); 
Fun2=inline('c2*cos(c3*x)-c1*y2-sin(y1)',... 
   'x','y1','y2','c1','c2','c3'); 
H=t/NN; 
% while 1; 
b=.3; 
y1=.1;y2=0; 
F=[];y=[]; 
j=0;x=0; 
Y=0.1; 
tt=1; 
while c2<=1.2; 
   y1=.1;y2=0;Y=0.1;j=0;x=0; 
   while y1<1.6; 
       y2=0;y1=Y; 
       for k=1:kk 
           for i=1:NN; 
               K1=H*Fun1(x,y2); 
               L1=H*Fun2(x,y1,y2,c1,c2,c3); 
               K2=H*Fun1(x+H/2,y2+L1/2); 
               L2=H*Fun2(x+H/2,y1+K1/2,y2+... 
                   L1/2,c1,c2,c3); 
               K3=H*Fun1(x+H/2,y2+L2/2); 
               L3=H*Fun2(x+H/2,y1+K2/2,y2+... 
                   L2/2,c1,c2,c3); 
               K4=H*Fun1(x+H,y2+L3/2); 
               L4=H*Fun2(x+H,y1+K3/2,y2+... 
                   L3/2,c1,c2,c3); 
               y1=y1+(K1+2*(K2+K3)+K4)/6; 
               y2=y2+(L1+2*(L2+L3)+L4)/6; 
               x=x+H; 
               if k==kk & i==8; 
                   y=[y,y2];F=[F,n];Y=Y+b; 
               end                 
           end 
       end 
       length(y) ;
   end 
   c2=c2+0.0005; 
   n=n+1;   
end 
figure; 
plot(F,y,'.','markersize',2)