| Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0 |
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Thanks for the quick response and analysis.
> Your matrix is indeed not very well conditioned for floats. Are you
> using fixed size matrices (Matrix4f) or dynamically sized ones
> (MatrixXf) ? I'm asking because there is a special path to invert 4x4
> fixed size matrices, and as far as I remember there was bug for some
> special configurations in the early versions of Eigen 2.0, so I would
> recommend you to upgrade it to the latest.
Fixed size, Matrix4f (I thought I included that in the post; sorry). Yes, I should upgrade but that's a little inconvenient in quite a large software system. Doable, and will be done!
>
> determinant != condition:
> http://en.wikipedia.org/wiki/Condition_number
>
> Matlab says the condition of your matrix is 3.8e8, which is pretty bad. (btw: is there a way to calculate condition with Eigen?)
I know that I wanted a condition number, and quoted the determinant as I couldn't find any eigen way of finding either the condition number, or whether it thinks that the inversion succeeded.
R