Time dependent parameters in ode

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PUJARI MURAGA
PUJARI MURAGA on 30 Oct 2016
Answered: winkmal on 13 Nov 2019
Let’s say an non-linear first order ode...> dy_dt= c1-c2*e^y+1
  • define t_span as t= 1:10 and initial value is 0.1
  • c1=[1 1 2 2 3 4 4 3 1 0] and c2=[1 1 2 2 3 4 4 3 1 1]
  • c1 & c2 is also vector of 1*10
  • For every change in value of t from t_i-1 to t_i, c1 and c2 values should be updated in ode and final value of iteration t_i-1 should be initial value to t_i .Please suggest me how to proceed
  3 Comments
PUJARI MURAGA
PUJARI MURAGA on 30 Oct 2016
Yes.exactly, at time t1, c1(1) and c2(1) should be updated with ic y0 and at time t2, c1(2) c2(2) should be updated with ic as y1......and so on
John D'Errico
John D'Errico on 30 Oct 2016
So use a spline. WTP? Or use interp1.
In your objective function, you know the value of t.
c1spl = spline(1:100,c1);
Pass it in and use it.

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Answers (1)

winkmal
winkmal on 13 Nov 2019
Here is MathWorks official answer, and the corresponding paragraph from ode45 documentation.
Note that interp1 does linear interpolation by default, so you might need to change that.

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