Re: [ublas] FWD: 2D Matrix

From: Gunter Winkler (guwi17_at_[hidden])
Date: 2006-11-09 07:47:24

On Thursday 09 November 2006 12:31, Maik Beckmann wrote:
> Hello
>
> It seems that many people thought about and worked on good performing
> small fixed matrix implementations.
> i.e.: http://thread.gmane.org/gmane.comp.lib.boost.ublas/2837/focus=2843

Thanks for the pointer.

> Since it wasn't mention AFAIK on this list yet, I want to point out that
> lately a IMHO good looking approach has been posted to boost-devel:
> http://thread.gmane.org/gmane.comp.lib.boost.devel/150571/focus=150571

I didn't check the code, but the replies state the problem: There are 3 
proposals that slightly differ. 

For my own programs I'd like to have a common interface for small, medium and 
large matrices and vectors. Some parts mainly operate on objects of size 2 to 
10, which are assembled into a large sparse matrix. Thus I frequently have to 
cast from double arrays to usable matrix/vector types.

This leads to these conclusions:
1. A library for (small) fixed size vectors and matrices is useful (and should 
be included into boost)
2. All boost libraries for linear algebra should have a common interface _and_ 
should contain types that are convertible or at least assignable to each 
other. (This is IMHO the goal of GLAS)
3. Actually there should be 3 libraries
  a) small (dense) objects  -> tvmet, 2D-matrix, ...
  b) large dense objects    -> dense part ublas, blas bindings
  c) (large) sparse objects -> sparse part of ublas, umfpack bindings

mfg
Gunter