Re: [eigen] get scaling out of transform?

[Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx>]

On Wed, 21 Jan 2009, Benoit Jacob wrote:

> There's another way that you can go, suffering again performance-wise
> from the current lack of fixed-size specializations: use the
> SelfAdjointEigenSolver.
>
> Transform3d t;
> Matrix3d m = t.linear();
> SelfAdjointEigenSolver s(m*m.adjoint());
> Matrix3d scaling = s.operatorSqrt();

This is numerically a bit dangerous. You lose information when computing 
the product m*m.adjoint(). This may not be that important in this case 
though, because the matrices are small and (I'd guess) the accuracy 
requirement is lax.


Jitse