Re: ENC: Trouble with symbolic on the Octave

[Colin Macdonald]

On 12/06/17 08:10 AM, Paulo Roberto wrote:
> I'm studying a discipline where we have to do calculations in Matlab. I 
> preferred to use Octave because it's a free software and the book I use 
> is one about Matlab (Matlab An Introduction with Applications by Amos 
> Gilat).
>
> My OS is Windows 7, the Octave is 4.2.1, the Symbolic Package is 2.5.0 
> and to implement Symbolic Math, I use the Anaconda Package, which has 
> the version 2.7.13 of Python and 1.0 for SymPy. But since the commands 
> I've quotes are not implemented in Octave, I'll leave them aside and go 
> on...

Even better, would be to file a bug for the missing "collect" function at:

https://github.com/cbm755/octsympy/issues

Your other two examples should work using "expand" and "simplify" 
respectively.

Note: there is no expectation that simplify-type commands work the same 
in different software platforms, different versions etc: AFAIK, its not 
a well-defined operation.

Colin


> *De: *"Doug Stewart" <address@hidden>
> *Enviada: *2017/06/12 11:35:57
> *Para: address@hidden
> *Cc: *  address@hidden
> *Assunto: *  Re: Trouble with symbolic on the Octave
>
> On Mon, Jun 12, 2017 at 10:26 AM, Paulo Roberto <address@hidden> 
> wrote:
>
>     Hello, Doug!
>
>     Some examples below:
>
>     1)
>      >> syms x y
>      >> S=(x^2+x-exp(x))*(x+3)
>     S = (sym)
>
>                    / 2        x\
>        (x + 3)*\x  + x - e /
>
>      >> F=collect(S)
>     error: 'collect' undefined near line 1 column 3
>      >>
>     it was expected F=x^3+4*x^2+(-exp(x)+3)*x-3*exp(x)
>
>     2)
>      >> syms x y
>      >> S=x*(x*(x-8)+10)-5
>     S = (sym) x*(x*(x - 8) + 10) - 5
>      >> SA=simplify(S)
>     SA = (sym) x*(x*(x - 8) + 10) - 5
>      >>
>     it was expected SA=x^3-8*x^2+10*x-5
>
>     3)
>      >> sym x
>     ans = (sym) x
>      >> s=(x^3-4*x^2+16*x)/(x^3+64)
>     s = (sym)
>
>         3      2
>        x  - 4*x  + 16*x
>        ----------------
>             3
>            x  + 64
>
>      >> F=simple(S)
>     error: 'simple' undefined near line 1 column 3
>      >>
>     it was expected F=x/(x+4)
>
>     I'll appreciate any assistance!
>
>     Thanks,
>
>     Paulo Roberto.
>
> you are using command that are not implemented.  what software are you 
> currently used to?
>
>
> _______________________________________________
> Help-octave mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/help-octave


--
Colin Macdonald
Associate Professor
Dept of Math, UBC