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Topic: Logistic equation with delay
Replies: 8   Last Post: Mar 24, 2014 3:42 AM

 Messages: [ Previous | Next ]
 Torsten Posts: 1,717 Registered: 11/8/10
Re: Logistic equation with delay
Posted: Mar 21, 2014 3:55 AM

> I am trying to solve a logistic equation with delay WITHOUT using dde23. So the delay is of the form: ddtN(t)=N(t)(a-bN(t-?t)),a>0,b>0
>
> I have a function called logistic that looks like this:
> function dN = logistic(t,N)
> global a b;
> dN = (a-N.*b)*N;
>
> And another file that calls this function with ode45 like this:
> global a b;
> a = 4;
> b = 1;
> [t, N] = ode45('logistic', [0:.01:5], 10);
>
>

ok, here you try to solve the _continuous_ logistic equation without delay.

> I think I understand how to write a for-loop to calculate the logistic equation with delay of 1 since I'm picking my ? to be 1; but I'm not getting the correct results. Here is the code:
> S=zeros(501,1);
> t=zeros(501,1);
> S(1)=0;
>
> for iterate=1:501
> S(i) = S(i-1) + r*S(i-1)*(1-b*S(i-1))
> end
> plot(t,S)
>

ok, here you try to solve the _discrete_ logistic equation without delay (although the case S(1)=0 is not that interesting)

>
> Any ideas?

And where do you try to solve the continuous logistic equation with delay ?

Best wishes
Torsten.

Date Subject Author
3/20/14 Sankar
3/21/14 Torsten
3/21/14 Sankar
3/21/14 Torsten
3/21/14 Sankar
3/21/14 Torsten
3/21/14 Steven Lord
3/21/14 Sankar
3/24/14 Torsten