Question about printing ode45 results

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Jaime De La Mota Sanchis 2019-11-12

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/490683-question-about-printing-ode45-results

评论： Daniel M 2019-11-12

Hello everyone. I have recieved a code in which an expression is called as [t, x]=ode45(@(t,x) example(t,x),tspan,x0); inside of it I have three vectors called u1d, u2d and u3d. I also have

u(1)=interp1(time,u1d,t,'linear');
u(2)=interp1(time,u2d,t,'linear');
u(3)=interp1(time,u3d,t,'linear');

I want to compare u(1) with u1d, u(2) with u2d and u(2) with u3d to see how good the interpolation is. The problem is that if I write

figure
plot(u1d)

inside of example, infinite figures appear.

Can someone please explain to me if it is possible to plot the points of u1d and compare them with the interpolated ones at u(1)?

I have tried to construct

u(1)=interp1(time,u1d,t,'linear');
u(2)=interp1(time,u2d,t,'linear');
u(3)=interp1(time,u3d,t,'linear');

outside of the ode45 function but error messages appear.

Thanks for reading.

Jaime.

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Jaime De La Mota Sanchis 2019-11-12

I have tried it your way and it works. Thanks.

Daniel M 2019-11-12

I will move it to an Answer then.

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采纳的回答

Daniel M 2019-11-12

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/490683-question-about-printing-ode45-results#answer_401156

You have the vectors time, and u1d (etc) outside of the ode45 call. And you also have the output t from the ode45 call. So,you can run an interpolation after calling ode45 (not inside).