Re: [boost] [pqs] Vector<3>

From: Hickerson, David A (david.a.hickerson_at_[hidden])
Date: 2006-06-14 16:56:37

I would suggest, not a vector3 or vector<3>, but to support math with 3D
transformation matrices, which is 4x4 matrix, with a vector4 or
vector<4>, if 3 space is the desired representation. When doing
transformations to vectors, you must use 1 dimension high than the level
you are working in. If done properly, quaterion support can also be
obtained, which is another way to represent rotations of vectors.

I believe we need these contruct to work together in a complete
solution, not just a piece.

Dave

-----Original Message-----
From: Janek Kozicki [mailto:janek_listy_at_[hidden]] 
Sent: Wednesday, June 14, 2006 2:46 PM
To: boost_at_[hidden]
Subject: Re: [boost] [pqs] Vector<3>

Geoffrey Irving said:     (by the date of Wed, 14 Jun 2006 12:49:56
-0700)

> On Wed, Jun 14, 2006 at 07:58:28PM +0100, Andy Little wrote:
> > "Janek Kozicki" wrote
> > > Geoffrey Irving said:     (by the date of Tue, 13 Jun 2006
09:30:39 -0700)
> > >
> > >> I would suggest that instead of trying to make an extremely 
> > >> general vector class, it'd be better to make an extremely 
> > >> specific vector class, together with an extremely general way to
other vector classes.
> > >>
> > >> Specifically, you can make vector3 (or vector<3>, perhaps) a 
> > >> straightforward single unit Euclidean vector.  It can have L2 
> > >> norms and L^inf norms and cross products and all the operations 
> > >> that are undefined for vectors with components of different 
> > >> units.  Then we could define a vector space variant of 
> > >> boost::operators to convert any tuple-like type into a vector
space type.
> > 
> > > PS: I like vector<3> , I think that Andy can't argue with this 
> > > name :>
> > 
> > I like it.  and I agree that it would be vector<3,T>. It conflicts 
> > with (later in the discussion) suggestions of tuple like behaviour 
> > though, however I like vector<3,T> primarily because mathematically 
> > challenged souls such as myself find it easier to understand. IMO 
> > Simplicity is an important and sometimes underrated design feature. 
> > The 3 there gives a good indication of what to expect. IOW the
vector<3,T> is "a straightforward single unit Euclidean vector"
> > as described by Geoffrey Irving.
> 
> And not quite off-topic: making that would have been rather nastier 
> without being able to templatize over dimension.  Debugging in 2d is a
lifesaver.
> Anything that makes that easier is good (vector<3,T> vs. vector3<T>).

good point.

-- 
Janek Kozicki                                                         |
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