[Insight-users] how to calculate the sqrt of a matrix

[Yonas Tesfazghi Weldeselassie]

Along the same line, once you have the

vnl_symmetric_eigensystem<double>  G(data);

you have got the eigenvalues. You may then compute the square root of the
eigenvalues and reconstruct the matrix which gives the desired result. The
same applies for calculating logarithm of a matrix.

===


On 4/15/07, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>
>
> Hi  Achille,
>
> Thanks for letting us know that you found the solution
> for computing the square root of the diagnolizable matrix.
>
>
>     Regards,
>
>
>         Luis
>
>
> --------------------
> achille mangna wrote:
> >
> >
> > sorry I wanted to say diagonalisable.
> > i finally resolve my probleme, as my matrix is symetric and positive
> > semi-definite , i used vnl_symetric_eigensystem (I had not seen it
> before)
> > there is function for "square_root" and "inverse_square_root"
> >
> > vnl_matrix<double> data;
> > vnl_symmetric_eigensystem<double>  G(data);
> > vnl_matrix<double> m_SphereMatrix= G.inverse_square_root();
> >
> > thanks for your help!
> >
> >
> >
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