[GiNaC-list] Polynomial companion matrix

[James Jackson]

Yes I suppose you're correct! I'm just using it to compute eigenvalues  
so using this transposed matrix works fine. The eigenvectors would of  
course be different.

Just swapping is and js should put it into 'normal' format.

Regards,
James.

On 18 Feb 2009, at 14:59, Jens Vollinga wrote:

> Hi James,
>
> James Jackson schrieb:
>> As far as I can see, there is no method available to compute the  
>> companion matrix of a polynomial. May I suggest the addition of a  
>> method along these lines?:
>
> sure, we can include such a function.
>
> I am just a bit confused about the conventions here:
>
>>    mat(i, j) = -1 * poly.coeff(symbol, rank - j - 1) / majorCoeff;
>
> Shouldn't coefficient c_j go in row j?
>
> Regards,
> Jens
>
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