[GRASS-dev] BLAS/LAPACK (Part II)

["Sören Gebbert"]

HI folks,

-------- Original-Nachricht --------
> Datum: Mon, 20 Aug 2007 12:29:14 +0300
> Von: Wolf Bergenheim <wolf+grass at bergenheim.net>
> An: GRASS Devel <grass5 at grass.itc.it>
> CC: Daniel Bundala <daniel.bundala at oriel.ox.ac.uk>, Brad Douglas <rez at touchofmadness.com>
> Betreff: Re: [GRASS-dev] BLAS/LAPACK (Part II)

> On 17.08.2007 07:09, Brad Douglas wrote:
> > 
> > What I propose is moving the matrix code from v.generalize 
> 
> +1
> 
> > (in particular, matrix_inverse() ) to lib/gmath and simplifying the
> existing
> > MATRIX structure.
> > 

I can easily integrate the matrix code from v.generailze into 
the gpde library, because the existing matrix structures are quite
similar. Quadratic and sparse matrices are supported.
The gpde library ships several vector-matrix and vector-vector
functions with it, but currently as static functions within the krylov-space solvers. I can make them public (extern), 
so they can be accessed from out side of the krylov solvers.

Many linear equation solvers are available 
within the gpde library:
* direct solvers
** gauss elimination
** lu decomposition
** cholesky decomposition.
* iterative solvers
** gauss seidel / SOR
** jacobi
** conjugate gradients (krylov space method)
** preconditioned conjugate gradients (krylov space method)
** biconjugate gradients stabilized (krylov space method)

Everything is multithreaded with OpenMP (solver, matrix, vector operations and some array functions).

And as you know, the lu code in gmath lib is a copy 
of the numerical recipes algorithm and not free. 

I would like to hear some suggestions.

Best regards
Soeren


> 
> I think that would be a good idea, especially if you also want to use
> that code. It is easier to maintain the code in one place.
> 
> Brad do you know of any additional mathematics or similar things you'd
> like to see in lib/gmath? Perhaps next year it could be a Summer of Code
> project to add them ;)
> 
> --Wolf
> 
> -- 
> 
> <:3 )---- Wolf Bergenheim ----( 8:>
> 
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