The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Software » comp.soft-sys.matlab

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 1,717
Registered: 11/8/10
Re: Logistic equation with delay
Posted: Mar 21, 2014 3:55 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

"Adin" wrote in message <lggbgg$95h$>...
> 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

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.