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## Re: Octave-symbolic package

 From: Donald MacKinnon Subject: Re: Octave-symbolic package Date: Sun, 22 Mar 2009 10:26:35 +0000 User-agent: Thunderbird 2.0.0.19 (X11/20090114)

```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

```
```

```

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