Re: [OctDev] Ode23s

[Juan P. C. <car...@if...>]

On Wed, Sep 5, 2012 at 11:07 AM, davide prandi <dav...@ho...> wrote:
> Hi everyone,
> I'm Davide Prandi, and I'm a student of Politecnico di Milano, electronic
> engineering. My professor of "Numerical computation" (he's present in this
> mailing list) asked me to develop a code that implements the "ode23s"
> method, present in matlab but not in Octave. Ode23s solves differential
> equations (like ode23, odepkg package), but is builted for "stiff" problems.
> I have referred to "The matlab ode suite (Shampine, Reichelt)", pp. 6-7,
> where Rosenbrock formula, a particular form of Runge-Kutta methods, is
> mathematically explained. My code is based on these formulas. Well, the code
> basically works, but there is some feature that must be fixed. In
> particular:
> 1) I use "dfxpdp.m" (optim package) for the Jacobian computing. It works,
> but it accepts equations in F(Y,t) form, and all the ode solvers require
> equations in form F(t,Y). There is a way to redefine F, swapping the
> dependent/independent variable? At moment, I'm testing the code putting the
> equations in F(Y,t) form.
> 2) There is an optional input in the function's prototype: "options". It use
> "odeset" to define some parameters,  for example user can change the initial
> integration step size. I've implemented some of these options, and certainly
> there is some things to do/fix.
>
> I hope that my work can be useful. If all the problems are fixed, I think
> that this code may be integrated in the "odepkg" package.
> How can I share the code? I enclose .m file or I copy all the code in a
> e-mail?
> Of course, I'm not a experienced programmer (this is the first time that I
> do a big project), I will accept all the advice.
> Thanks to all,
>
> Davide
>
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Hi Davide

You can share your code using the Feature Request forum
http://sourceforge.net/tracker/?group_id=2888&atid=352888

Just upload your file (if you have more than one, compress them) and
send an e-mail to this mailing list. Then the interested people will
look at your code, send you comments on style and maybe even test it!

Thank you for your collaboration.

JPi



-- 
M. Sc. Juan Pablo Carbajal
-----
PhD Student
University of Zürich
http://ailab.ifi.uzh.ch/carbajal/