Re: [eigen] Rigid Transformations in eigen: discussion thread

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On Thu, Sep 17, 2009 at 10:01 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>> b) How does eigen do say, 4D rotations? I thought it did only 2D and
>> 3D rotations. I don't know if rigid transformations make sense for 2D.
>> At any rate, 2D transformations are trivial.
> 4D rotations? What's this?
> I guess that would be "4x4 real orthogonal matrices with determinant 1
> and with the eigenvalue 1 with multiplicity at least 2"
> whee! no, we don't have a class for that :)
>> c) Inverse would be good, I agree. You just need to do take take the
>> conjugate of both the quaternion parts.
> Inverse sounds useful indeed. Don't know about the formula, i trust you =)
Inverse is pretty trivial actually. You just take conjugates of the
two quaternions.
> transform conversion sounds useful too.
> Benoit

Rohit Garg

Senior Undergraduate
Department of Physics
Indian Institute of Technology

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