Re: Octave-symbolic package

[Donald MacKinnon]

Wolfgang Lindner wrote:
> hi Ben,
>
> why not use the GNU CAS Maxima 5.17 in a window parallel with octave?
> Or try SAGE - but that's big ..
>
> HTH
> Wolfgang
Sometimes that isn't too easy.
I have used a matlab script which originated in Aston University, UK, 
involving finding piecewise polynomials.  The octave routines worked 
fine until one routine symspline(m,t), was required to execute a step in 
the process which required the generation of a symbolic structure. I 
tried everything I could to get the octave symbolic package to give the 
required algebraic output. I think it involves a matrix internally 
defined, it could also involve operator overloading.  Using Maxima in 
places sounds plausible but sometimes its impractical.

Octave performed all the other Matlab tasks very well.
Donald



> -----Ursprüngliche Nachricht-----
> Von: Benjamin Brown <address@hidden>
> An: address@hidden <address@hidden>
> Datum: Samstag, 21. März 2009 20:30
> Betreff: Octave-symbolic package
>
>
> > Hello,
> >
> > I come from a Matlab background, but I've been trying to migrate to octave.
> > The most important thing that I've been missing is the symbolic toolbox.
> > Then I found octave-symbolic.  The only issue I'm having is that the usage
> > seems to be a bit different from the Matlab toolbox.  I've defined a number
> > of symbols, z, z_p, b, and a using:
> >
> > z=sym("z")
> > z_p=sym("z_p")...
> >
> >
> > without error.  Then when I try to create an expression:
> >
> > k=e^(i*b(sqrt((z-z_p)^2+a^2)))/(4*pi*sqrt((z-z_p)^2+a^2))
> >
> > I get the following errors:
> >
> > error: mapper: wrong type argument `ex'
> > error: evaluating argument list element number 1
> > error: evaluating binary operator `*' near line 11, column 7
> > error: evaluating binary operator `^' near line 11, column 4
> > error: evaluating binary operator `/' near line 11, column 31
> > error: evaluating assignment expression near line 11, column 2
> >
> >
> > Is there any way you could send me some basic usage sample code for this
> > package.  Any help would be appreciated.
> >
> > -Benjamin Brown