Re: [Pysparse-users] Factors in Umfpack: contribution to PySparse

[Daniel W. <dan...@gm...>]

I committed the changes and bumped the version number. I'll hold off
on a release
unless there is a pressing need.

Cheers

On Jan 28, 2008 4:34 PM, Dominique Orban <dom...@gm...> wrote:
> Hello,
>
> I wrote an addition to the UMFPack module of PySparse that lets users
> retrieve the details of the factorization. Here is an example:
>
>  from pysparse import spmatrix, umfpack
>  A = spmatrix.ll_mat_from_mtx('bcsstk11.mtx')
>  LU = umfpack.factorize(A)
>  (L, U, P, Q, R, do_recip) = LU.lu()
>
> The help of lu() is as follows:
>
> -------
> lu(...)
>     self.lu()
>     Returns L and U factors, permutation and scaling information.
>
>     Use: (L, U, P, Q, R, do_recip) = self.lu().
>     The original matrix A is factorized into
>          L U = P R A Q
>     where L is unit lower triangular,
>           U is upper triangular,
>           P and Q are permutation matrices,
>           R is a row-scaling diagonal matrix such that
>            the i-th row of A has been divided    by R[i] if do_recip = True,
>            the i-th row of A has been multiplied by R[i] if do_recip = False.
>
>     L and U are returned as ll_mat sparse matrices.
>     P, Q and R are returned as NumPy arrays.
> -------
>
> I would very much like to see this function included in PySparse. I
> will e-mail the code directly to Daniel Wheeler.
>
> Comments welcome.
>
> Cheers,
> Dominique
>
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-- 
Daniel Wheeler