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