[GiNaC-list] bug with is_polynomial?
varg at theor.jinr.ru
Wed Aug 6 08:58:29 CEST 2008
On Tue, Aug 05, 2008 at 01:58:59PM -0700, Jonathan Cross wrote:
> When there is an expression involving a non-integer power---even when
> the expression is independent of the dummy variable of the polynomial---
> then the expression is not considered a polynomial by GiNaC.
Mathematically such an expression is not a polynomial (over field of
rational numbers). See you favourite book on the (commutative) ring
theory for more details.
> // here are two expressions that are both polynomials with respect to s.
> GiNaC::ex expr1 = sin(x) + 2*s;
> GiNaC::ex expr2 = pow(2,x) + 2*s;
I don't quite understand why these expressions are polynomials. Could
you elaborate, please?
All science is either physics or stamp collecting.
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