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Rebuilding polygon from CoefficientList?

• To: mathgroup at smc.vnet.net
• Subject: [mg20164] Rebuilding polygon from CoefficientList?
• From: "Holger Strauss" <strauss at ika.ruhr-uni-bochum.de>
• Date: Sun, 3 Oct 1999 21:07:34 -0400
• Organization: Ruhr-Universitaet Bochum, Rechenzentrum
• Sender: owner-wri-mathgroup at wolfram.com

Hallo,

I have a mixed polynomial poly in several variables vars.

cl = CoefficientList[poly, vars]

gives a multi-dimensional matrix of coefficients.

Can anyone help with an algorithm/expression that
re-constructs the original poly given cl and vars?
(In practice, I'd like to manipulate the coefficients before
reconstructing the polynomial; otherwise this wouldn't
make sense).
The algorithm must be able to handle any number of vars.
I've found a solutions for a small and fixed number of vars
using some ugly nested For loops. However, I suppose
that there must be a more efficient solution using some cute
matrix operations.

Many thanks,
Holger


Holger Strauss
Institute of Communication Acoustics
Ruhr-University Bochum

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