Matlab ODE Solvers - Paramater Question

Greetings,

I working with a system of differential equations that model amount of components as a reaction proceeds. I want to pass a variable parameter through one of matlab's ode solvers (probably 45/15). This is in addition to time bounds, so it would be like ode45(function, times, [X1(0),X2(0),...X5(0)],... ). I want to find λ given something like X1(final) = 0.35. How to include this information?

Thank you (:

Answer 1

[Walter Roberson]

To pass an additional parameter, use http://www.mathworks.com/help/matlab/math/parameterizing-functions.html

However... for the task of finding X1(final) = 0.35 you should be using one of the Boundary Value Problems solvers; https://www.mathworks.com/help/matlab/boundary-value-problems.html

[Joe]

--Thank you!

Answer 2

[Torsten]

You mean

ode45(@(t,y)fun(t,y,lambda),times,[X1(0),X2(0),...X5(0)])
    
function res = fun(t,y,lambda)
   ...
end

? But what do you mean by "variable parameter" ? This is a contradiction in itself: A parameter isn't variable.

[Joe]

Thanks! How I include the extra final condition? Would that go in ode45 line?

[Torsten]

If you have a final condition for one of the unknown functions, you should use "bvp4c" instead of "ode45".