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Re: Horner's method on subexpressions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg17422] Re: Horner's method on subexpressions
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Thu, 6 May 1999 02:44:26 -0400
  • Organization: Universitaet Leipzig
  • References: <7gjeaa$cmh@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Ben,

does pattern matching help you

<your expression> /. Re[a_] :> Re[Horner[a]]

Regards
  Jens


Ben Raphael wrote:
> 
> I have a sequence of expressions that contain polynomials and other
> terms.  An example is an expression of the form:
> 
> 1/2 Re[-2/x^28 + 2(1+x)^56 / x^28] + Re[(1 / (-1 + 2x)^29) (high degree
> polynomial in x)]/483298748
> 
> The polynomials that appear have integer coefficients.  What I would
> like to do is rewrite this expression by applying the Horner[] function
> to the polynomial, in order to speed up evaluation.  However, the Horner
> function only takes polynomial arguments, so one way to proceed is to
> extract the polynomial term, apply Horner and then reconstruct the
> expression.  Does anyone know an efficient way to do this, or have
> method to suggest?
> 
> Thanks,
> 
> Ben Raphael
> braphael at ucsd.edu


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