Re: ode45 Matlab -> Octave

[Jordi Gutiérrez Hermoso]

On 17 December 2012 21:44, alexvas <address@hidden> wrote:
> I am an avid user of Matlab, but currently only have access to Octave. My
> Matlab script uses ode45 (which is not native to Octave, so I downloaded an
> ode45.m from sourceforge),

I would not say that ode45 "is not native to Octave". It happens to be
in the odepkg Octave-Forge package. Depending on your OS, there are
different ways to install that package. I assume you only got one
m-file from that package, but it's not clear to me at all that that
single m-file will work alone in isolation from the rest of the
functions in odepkg.

Before trying to see if ode45 has the problems you describe, can you
confirm that you did install all of odepkg and the method you followed
to do so?

Also, I don't know why ode45 seems to be the only ODE solver that
Matlab users ever use. I assume it's because it's the only ODE solver
that they learned about in undergraduate courses. Even Matlab has a
bunch of other solvers, and ode45 is not a very good one in general.
For example, it can't solve stiff systems. Octave core has lsode,
which works quite similarly, but it can handle some stiff systems.

Furthermore, your snippet isn't enough to diagnose your problem. Can
you post a complete working example of the code you're running that
doesn't produce the output you expect?

- Jordi G. H.