| Re: [eigen] Patch for quaternion normalization and cross product for Vector4f |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Patch for quaternion normalization and cross product for Vector4f
- From: Rohit Garg <rpg.314@xxxxxxxxx>
- Date: Wed, 11 Mar 2009 17:50:16 +0530
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Hi,
<snip>
> About the cross product:
> I can't make myself a strong opinion either way. I was concerned of
> maintainance and porting to other archs, but it seems to factor well
> through our wrappers. My main concern now is that it's going to be
> little used. On the other hand, it could be the first of a collection
> of functions working on 3d vectors stored as 4d vectors for
> vectorization; I would be OK to start a new subdirectory of
> unsupported/ containing such functions. After all there is a demand
> for such functions, but they fit poorly with the rest of Eigen (until
> perhaps we find a better API -- one possibility might be to have a
> variant of the Matrix class itself doing storage differently and
> reimplementing these methods) and put a much bigger burden of the user
> to take care of low-level aspects, but in unsupported/ that's ok.
If it goes into unsupported, I have no problem. If you want to put it
in a specialized Matrix class with some extra load on user, no
problems there either. I do see your point that it could later be the
reason for people using vector4d for vector3d operations, but as you
said, it will be perhaps better suited for unsupported side of API
till cleaner API emerges. Regarding it' use, I'll use it but yes, it
may turn out to be relatively lesser used thing. But hey, why should
less use be held against so small functions which are obviously
faster?
> Your patch also contains a vectorized quaternion product. That would
> be extremely useful, I wonder why you dont mention it in your email?
> Do you consider it unfinished? I may also be out of date if Gael
> vectorized it already since the last time I checked.....
Gael already committed that. It was part of an earlier patch though.
Regards,
--
Rohit Garg
http://rpg-314.blogspot.com/
Senior Undergraduate
Department of Physics
Indian Institute of Technology
Bombay