[Insight-developers] itkVector, itkPoint and vnl_vector

[Will Schroeder]

Hi Luis-

I think that you are proposing a good solution. I'll check to see if Brad
has anything to say about it, since he implemented much of the
itkMesh class. I do like the idea of having points and vectors that
plug and play with vnl.

Will

At 03:43 PM 1/3/2001 -0500, you wrote:
>Will Schroeder wrote:
>
>> Hi Jim-
>>
>> In that case I would argue that itkVector should not 
>> be implemented with vnl_vector :-) I think memory issues
>> are very important. My experience with big data sets 
>> is that the difference between choosing one package over 
>> another often boils down to its performance when the data 
>> is large, which is usually a function of memory as the 
>> system strains to swap, etc.
>>
>> Will
>
>Given that a lot of this will be used only in 2D and 3D
>maybe it could be worth to specialize a set of (Vector, 
>Point, AffineTransformation) for 2D/3D without using 
>vnl_vector's (to respect the memory constrains), and keep 
>a generic set (Vector,Point AffineTransform) for N-D 
>using the vnl_vector.
>
>
>The extra bytes that vnl_vector costs will be less
>significant in higher dimensions, and it is in those
>higher dimensions that we don't want to do matrix 
>multiplications 'by hand'.
>
>
>If the same API is maintained for both sets, that
>could be a balance between speed, memory usage
>and code reuse.
>
>
>Luis
>
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