From help-request at octave dot org Tue Jan 11 09:30:57 2005
Subject: Re: ODE system solving
From: Geraint Paul Bevan <g dot bevan at eng dot gla dot ac dot uk>
To: octave help mailing list <help at octave dot org>
Date: Tue, 11 Jan 2005 15:25:42 +0000

homer_jay at katamail dot com wrote:
> i've tryed with odessa:
> 
> T0=520;
> Ta=25+273;
> w0=3.4;
> y0=[w0 p T0];
> z=linspace(0,L,L)';
> y=odessa("SysO",y0,p,100,z);
> plot(z/L,(y(:,3)-Ta)/(T0-Ta))
> 
> 
> it doesn't work! 
> "error: "P" undefined near line...."
> i think i can set a parameter "p" for Odessa, ins't it? it's something wrong?

P should be a vector of parameters. odessa will use these to find the
sensitivity of the states to changes in these parameters. Unless you
want to use these sensitivities, there is probably not much reason to
use odessa.

Octave is a matrix algebra tool, not a computer algebra system. Unless
you are using a symbolic toolbox, values should be assigned to all
variables before you use them. The error message occurs because you have
passed p to the function without first giving it a value.


-- 
Geraint Bevan
http://www.mech.gla.ac.uk/~gbevan




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