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Re: [Help-gsl] hi :-) \o/ I've some problem with eigensystem
From: |
Giuseppe Marco Randazzo |
Subject: |
Re: [Help-gsl] hi :-) \o/ I've some problem with eigensystem |
Date: |
Thu, 22 Apr 2010 17:03:23 +0200 |
User-agent: |
KMail/1.13.2 (Linux/2.6.33-gentoo-r1; KDE/4.4.2; x86_64; ; ) |
On Thursday 22 April 2010 10:20:39 tuc wrote:
> hi
>
> > So the point of question is this: the
> > results that i get have the right values but the signs wrong.
>
> let A be a square matrix. then a eigenvector v to the eigenvalue a is
> defined to have the property:
> A*v=a*v.
>
> therefor for any real number x (nonzero, zero is never an eigenvector)
> x*v is also a eigenvector of A:
> A*(x*v)=x*(A*v)=x*(a*v)=a*(x*v)
ok!! i've read now the second example that say:
"Note that the eigenvectors can differ by a change of sign, since the sign of
an eigenvector is arbitrary.
The following program illustrates the use of the nonsymmetric eigensolver,"
ok :) so with this example now the sings are ok! :-)
Thanks for support :-)