How to get as output the values of a parameter which change over time, but is not a derivative, in a function with an ODE system

Hello everyone,

I have an ODE system like this, with 2 variables D and S:

function dy = deri(t,y,par) %par are a, b, c, d, hb y=[1 0]

dD= a * (c - D);

h = b * max(0,D-d); %h is calculate based on D at each time point

dS = -(h + hb)* S;

dy = [dS;dD]; % collect derivatives in one vector

My question is how to get as output the values of h over time?

I tried to add it as input like a variable and thus as output dy = [dS;dD;h], but it seems the values return are not correct

Thank you very much in advance for your answers

Sylvain

Answer 1

[Naveen Venkata Krishnan]

Hello Sylvain,

Can you try this once, after the execution of ode you will be having D(t) , S(t) over the specified tspan. Try calling another function that takes D(t) and gives out h(t) over the same tspan.

%-ode part-----
h = cal_h(D,b,d);

Function:

function H  = cal_h(D,b,d)
    H = zeros(size(D,1),1);    
    H   = b * max(0,D-d);
end

Am not really sure whether this is what you might be looking for but i hope this helps you a bit.

[Sylvain Bart]

Thank you, your answer was useful

Cheers,

Sylvain