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## Re: Octave-symbolic package

 From: Sergei Steshenko Subject: Re: Octave-symbolic package Date: Sun, 22 Mar 2009 08:07:25 -0700 (PDT)

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--- On Sat, 3/21/09, Benjamin Brown <address@hidden> wrote:

> Subject: Octave-symbolic package
> Date: Saturday, March 21, 2009, 11:22 AM
> 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
>

"lookfor symbolic" shows:

symbols              Initialize symbolic manipulation
Cos                  Return the cosine of a symbolic expression.
Cosh                 Return the hyperbolic cosine of a symbolic expression.
Exp                  Return the exponential of a symbolic expression.
Log                  Return the logarithm of a symbolic expression.
Sin                  Return the sine of a symbolic expression.
Sinh                 Return the hyperbolic sine of a symbolic expression.
Sqrt                 Return the square root of a symbolic expression.
Tan                  Return the tangent of a symbolic expression.
Tanh                 Return the hyperbolic tangent of a symbolic expression.
aCos                 Return the inverse cosine of a symbolic expression.
aCosh                Return the inverse hyperbolic cosine of a symbolic
expression.
aSin                 Return the inverse sine of a symbolic expression.
aSinh                Return the inverse hyperbolic sine of a symbolic
expression.
aTan                 Return the inverse tangent of a symbolic expression.
aTanh                Return the inverse hyperbolic tangent of a symbolic
expression.
degree               Return the degree of a symbolic expression.
findsymbols          Returns the symbols in symbolic expression F in a list.
is_ex                Return true if an object is a symbolic expression.
lcoeff               Return the leading coefficient of a symbolic expression.
ldegree              Return the low degree of a symbolic expression.
numden               Return the numerator and denominator of symbolic
expression F.
premainder           Return the pseudo-remainder of a symbolic expression.
quotient             Return the quotient of a symbolic expression.
remainder            Return the remainder of a symbolic expression.
syminfo              Returns information regarding the nature of symbolic
expression EQN in a structure.
tcoeff               Return the trailing coeffiecient of a symbolic expression.
splot                Plot a symbolic function f(x) over range.
sym2poly             Returns the coefficients of the symbolic polynomial
expression P as a vector.
poly2sym             Creates a symbolic polynomial expression P with
coefficients C.
symfsolve            Solve a set of symbolic equations using fsolve().

But I myself use 'maxima', and am closely looking at other CAS packages.

Regards,
Sergei.

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