[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Help with ODE solver

From: Douglas Eck
Subject: Re: Help with ODE solver
Date: Thu, 12 Sep 2002 09:05:18 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.1b) Gecko/20020722

Hi Marco,
My experience is that it's better to break down the integration into
intervals. Also, if you later need to speed up your code some, it can
be much faster to write the xdot = f(x,t) as a compiled .oct file.

Marco Antoniotti wrote:

I am using the LSODE solver for my research and now need to do the

At a time t_i, I need to change the value of one (or more) of the
variable(s) involved.

I think I understand I have two avenues to follow to achieve this
goal, but, given my inexperience with Octave (and/or Matlab) I don't
know which is the best one.

1 - I could insert a specific test in the derivative function

  function xdot = f(x, t)
    xdot = zeros(rows(x), 1);

    if (t == t_i)
       ## set x(k) to M

    xdot(1) = ...
    xdot(n) = ...


2 - I could break down the integration into intervals and set the
    variable value between integrations.

I'd like some comments about what would be the "best" (for an
approrpiate definition of "best") way to achieve this goal.


Dr. Douglas Eck,
Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA)
Neural Networks, Rhythm Perception and Production, Dynamical Systems

Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:
How to fund new projects:
Subscription information:

reply via email to

[Prev in Thread] Current Thread [Next in Thread]