请问如下的分岔图错在那?

xiangwei27

在曲面y(2)=-0.5*y(1)+0.00004作poincare映射关于f与y(1)的分岔图，坐标f是0.00035到0.00055,y(1)是-0.03到 -0.01。程序如下：
global f;
rang=0.00035:0.00001:0.00055;
hold on
for f=rang
    [t,y]=ode45(@Xiang10,[0,10000],[-0.031,0.01,0.01,0.02]);
    if abs(y(2)+0.5*y(1)-0.0004<0.001)
        plot(f(j),y(:,1)),hold on
    end
end
其中
function dx=Xiang10(t,y);
global f;
w1=1.0;w2=0.515;
s1=0.03;
s2=0.004;
c1=0.005;
c2=0.005;f=0.000497;
dy=[-1/2*c1*y(1)-s2*y(2)+3*w2*w2/(4*w1)*y(3)*y(4);
-1/2*c1*y(2)+s2*y(1)-3*w2*w2/(8*w1)*(y(3)*y(3)-y(4)*y(4))+f/(2*w1);
-1/2*c2*y(3)-1/2*(s2-s1)*y(4)-1/4*(2*w1-w2)*(y(1)*y(4)-y(2)*y(3));
-1/2*c2*y(4)+1/2*(s2-s1)*y(3)-1/4*(2*w1-w2)*(y(1)*y(3)+y(2)*y(4))];

[ 本帖最后由 eight 于 2008-4-7 16:09 编辑 ]