Solving non homogenous differential equations numerically using ode45 etc

Question

Sarah Ghosh 2014-10-28

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https://ww2.mathworks.cn/matlabcentral/answers/160461-solving-non-homogenous-differential-equations-numerically-using-ode45-etc

评论： Mischa Kim 2014-11-4

How is a non homogenous differential equation solved in MATLAB using ode45 or ode23. I have a function like:- dmdt = a*exp(Asin(wt) + (2-m)^2);

Can I obtain the numerical solution for this?

Thanks in advance

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Answer 1

Mischa Kim 2014-10-29

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https://ww2.mathworks.cn/matlabcentral/answers/160461-solving-non-homogenous-differential-equations-numerically-using-ode45-etc#answer_156996

编辑：Mischa Kim 2014-11-4

在 MATLAB Online 中打开

Sarah, yes you can. The typical approach for such an example is to create two functions:

 function my_EOM()
 a     = 1;
 A     = 1;
 w     = 1;
 fun   = @(w,x) sin(w.*x);
 param = {a; A; w; fun};
 IC    = -1;
 [t,m] = ode45(@EOM,[0 1],IC,[],param);
 plot(t,m)
 xlabel('t')
 ylabel('m')
 grid
 end
 function dmdt = EOM(t, m, param)
 a   = param{1};
 A   = param{2};
 w   = param{3};
 fun = param{4};
 dmdt = a*exp(A*fun(w,t) + (2 - m)^2);
 end

Save both functions in the same .m-file and with name my_EOM.m. Execute and enjoy.

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Sarah Ghosh 2014-11-4

Thanks for your answer, but is there no possible way to pass the external input to the ode function (here, EOM). I basically want to plot and check the external input and the solution obtained via the differential equation. So, I need the external input in the my_EOM function so that I have both these two as vectors. Is there any way to do that? Or do I just create the input again in my_EOM?