How can I calculate Y with the program(ODE45_main and ODE45_fun)?

Question

Lan 2015-3-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/183543-how-can-i-calculate-y-with-the-program-ode45_main-and-ode45_fun

回答： Lan 2015-3-24

采纳的回答： Lan

在 MATLAB Online 中打开

MATLAB program：

 x y z b c is x(1——5)， Y isn’t in the program
ODE45_fun【m.file】：

function dx=ODE45_fun(t,x)

dx = zeros(5,1); % a column vector

a1=1;a2=1;e1=9;e2=7;f1=56;f2=98;g1=76;g2=665;

a=a1+a2; e=e1+e2; f=f1+f2; g=g1+g2;

dx(1)=x(3)-x(2)+x(4)*x(2)-2*x(5)*x(2)-x(2)*x(2)-x(5)-e-f-g;

dx(2)=x(1)-x(3)+x(4)*x(2)-x(2)*x(2)-x(5)*x(5)-x(5)*x(2)-e*f-g;

dx(3)=x(2)-x(1)+x(5)*x(1)-x(4)*x(3)+x(3)+x(4)+e*g+f;

dx(4)=x(5)*a+x(3)*x(1)+x(3)+e*f*g*(x(4)*x(5)+x(2)*x(3)+e*f+e*g)

dx(5)=x(4)*a+x(2)*x(1)-e*f*x(1)-x(2)*x(2)*x(5)-x(2)*x(5)*x(5)-e*f-f*g

dx=[dx(1);dx(2);dx(3);dx(4);dx(5)]; %dx=[dx(1);dx(2);dx(3);dx(4);dx(5);dx(6)];

ODE45_main【m.file】：

tspan=[0,1e-5];

x0=[0;0.1;2;0;0.1];

[t,x]=ode45('ODE45_fun',tspan,x0);

data=[t,x];

save ODE45_data.txt data -ascii

subplot(2,3,1),plot(t,x(1))

subplot(2,3,2),plot(t,x(2))

subplot(2,3,3),plot(t,x(3))

subplot(2,3,4),plot(t,x(4))