Re: Octave-symbolic package

[Donald MacKinnon]

Benjamin Brown wrote:
> 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
>
> Hello Ben,
It may or may not help but if you look at the the website 
octave.sourceforge.net/doc/funref_symbolic.html
it list some routines which test for the variable type in use etc. Now 
knowing the type of variable or function you are dealing with, may guide 
you towards what is wrong. For example "wrong type argument `ex'". Now 
the  funref_symbolic.html page gives you a test for the type 'ex', i.e. 
is_ex.
This helped me but it didn't solve my problem. Mine I think was that an 
array was expected but when the routine was given an array it still 
objected. Perhaps octave symbolic can't handle arrays yet.

I hope the above helps you.
Donald


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