# [Maxima] eigen vectors and eigen values

Chibisi Chima-Okereke chibco at gmail.com
Wed Jun 18 13:39:17 CDT 2008

```Thanks for your help

On Wed, Jun 18, 2008 at 7:15 PM, Raymond Toy (RT/EUS) <
raymond.toy at ericsson.com> wrote:

> Chibisi Chima-Okereke wrote:
>
>> Dear all,
>>
>> I am probably doing something silly and don't realise it but here goes...
>>
>> I am trying to find the eigen values and eigen vectors of a matrix, but
>> maxima keeps giving me an error (run on win XP in wxMaxima)
>>
>> (%i37)E:
>> matrix([1,-1,0,0,0,0,0],[-1,3,-1,0,-1,0,0],[0,-1,3,-1,0,-1,0],[0,0,-1,3,0,0,-1],[0,
>>  -1,0,0,3,-1,0],[0,0,-1,0,-1,4,-1],[0,0,0,-1,0,-1,4]);
>>
>> (%o37)
>> matrix([1,-1,0,0,0,0,0],[-1,3,-1,0,-1,0,0],[0,-1,3,-1,0,-1,0],[0,0,-1,3,0,0,-1],[0,-1,0,0,3,-1,0],[0,0,-1,0,-1,4,-1],[0,0,0,-1,0,-1,4])
>>
>> (%i38) eigenvalues(E);
>>
>> solve is unable to find the roots of the characteristic polynomial.
>>
>> (%o38) []
>>
>>
>>  Maxima wants to do this symbolically.  The characteristic polynomial is
> of order 7.  Do you know how to get symbolic roots from a 7'th order
> polynomial?  Neither does maxima. :-(
>
>  I have tried the same problem in R and I get an answer (in the blink of an
>> eye). Can anyone let me know what the problem is?
>>
>
> Perhaps eigens_by_jacobi will do what you want.  Or you can load(lapack)
> and use dgeev to get the eigenvalues/vectors for this matrix.
>
> Ray
>
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