Re: [Lib2geom-devel] [Inkscape-devel] Help with numpy.linalg.solve

[Partha B. <par...@gm...>]

What about umfpack (http://www.cise.ufl.edu/research/sparse/umfpack/ )?
Already being used in GEGL.

Thanks,
Partha



On Fri, Apr 11, 2014 at 7:34 AM, Alex Valavanis <val...@gm...>wrote:

> Well, it depends on the format of the matrix. If it can be arranged into a
> tridiagonal form, then it can be inverted much faster using [1].
>
> If it's a general sparse matrix (i.e., there is some data away from the
> three main diagonals), then unfortunately there's nothing available in GSL.
>
> Armadillo supports eigenvalue searches in sparse matrices (although you
> can only get selected eigenvalues) but doesn't support sparse matrix
> inversions yet.
>
> There are a couple of older libraries like libsparse++ and arpack++ that
> may be useful although their API is the stuff of nightmares!
>
> Let me know what the maths looks like and I'll see if I can find something
> useful :)
>
> AV
>
> [1]
> http://www.gnu.org/software/gsl/manual/html_node/Tridiagonal-Systems.html#Tridiagonal-Systems
>
> On 11 April 2014 12:18, Tavmjong Bah <tav...@fr...> wrote:
> > On Fri, 2014-04-11 at 12:02 +0100, Alex Valavanis wrote:
> >> Jabier,
> >>
> >> Can you give some information about the type of problem you're trying
> >> to solve? The LU decomposition approach is fine for general matrix
> >> inversions, but there are much faster algorithms available for sparse
> >> matrices.
> >
> > Alex,
> >
> > What would you recommend for sparse matrices? I have a long term
> > Inkscape project that needs this.
> >
> > Thanks,
> >
> > Tav
> >
> >
> >
>
>
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