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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Rigid Transformations in eigen: discussion thread
- From: Rohit Garg <rpg.314@xxxxxxxxx>
- Date: Thu, 17 Sep 2009 22:21:09 +0530
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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
http://rpg-314.blogspot.com/
Senior Undergraduate
Department of Physics
Indian Institute of Technology
Bombay