[Date Index] [Thread Index] [Author Index]

Re: matrices & polynomials in mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg27275] Re: matrices & polynomials in mathematica
• From: Erich Mueller <emuelle1 at uiuc.edu>
• Date: Sat, 17 Feb 2001 03:30:47 -0500 (EST)
• Organization: University of Illinois at Urbana-Champaign
• References: <96iqj6$d90@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

You could try replacing Power with MatrixPower.  Here is an example:

Poly = (1 + x)^3 + 2;
clist = CoefficientList[Poly, x]; 
MatPoly = (MatrixPower[x, #] & /@ (Range[Length[clist]] -1)).clist

Erich

On 16 Feb 2001, news.tue.nl wrote:

> Hi,
> 
> I have the following problem.
> I have written a mathematica-module that automatically produces a certain
> polynomial as a result. But I want another module to use this first module
> and fill in a matrix in this polynomial.
> for example: f[x]=1+x+x^2
> But when I compute f[A] where A is a matrix, mathematica interprets 1 as a
> matrix filled with ones in stead of the identity-matrix. And A^2 is
> pointswise multiplication in stead of matrix-multiplication.
> Is there an option to let Mathematica know that the polynomial works on
> matrices?
> 
> Chris
> 
> PS. I am aware of the possibility to multiply matrices using . (dot) but the
> problem is that the polynomial is the result of some computations and I need
> to have mathematica interpret this polynomial on matrices automatically.
> 
> 
> 
> 
>