dolfin team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

On Mon, 2006-07-10 at 20:07 +0200, Anders Logg wrote:
> Great. How does it compare to solving with a dense uBlas matrix (for a
> reasonably small system) and using the "built-in" uBlasMatrix::solve()?
> 

I haven't done a comparison. I suspect that for small systems
uBlasMatrix::solve() will be faster since UMFPACK wants the matrix in
compressed column format, so that would have to be created, and UMFPACK
does some fancy symbolic analysis and reordering which will have some
overhead but won't help for dense matrices. Should be pretty easy to
set-up a benchmark and test though.

I'll move uBlasMatrix::solve() to uBlasLUSolver shortly (initially for
dense matrices only).

Garth



> /Ander
> 
> On Mon, Jul 10, 2006 at 06:37:06PM +0200, Garth N. Wells wrote:
> > On Mon, 2006-07-10 at 18:32 +0200, DOLFIN wrote:
> > > One or more new changesets pushed to the primary DOLFIN repository.
> > > A short summary of the last three changesets is included below.
> > > 
> > > changeset:   2054:0691435ba8b47358c9c50a363ac3424c24ca8420
> > > tag:         tip
> > > user:        "Garth N. Wells <g.n.wells@xxxxxxxxxx>"
> > > date:        Mon Jul 10 18:13:24 2006 +0200
> > > files:       configure configure.ac src/kernel/la/dolfin/uBlasLUSolver.h src/kernel/la/dolfin/ublas.h src/kernel/la/uBlasLUSolver.cpp src/test/Makefile src/test/main.cpp
> > > description:
> > > Use UMFPACK (if installed) for LU solution of uBlas matrices.
> > > 
> > 
> > The direct solver for uBlas data types now uses UMFPACK (which is very
> > fast) if it's installed, otherwise it uses a Krylov solver. When UMFPACK
> > is installed, the demos in src/demo/pde run nice and fast with uBlas
> > matrices and vectors.
> > 
> > If you have a Debian-based distribution, you can install UMFPACK by
> > doing
> > 
> >     apt-get install libumfpack4 libumfpack4-dev 
> >     
> > Packages are available for most common Linux distributions under the
> > name "umfpack" or "ufsparse".
> > 
> > Garth
> > 
> > 
> > > 
> > > changeset:   2053:10663473e69cf9ea1824380b0ef1181744696623
> > > user:        "Garth N. Wells <g.n.wells@xxxxxxxxxx>"
> > > date:        Fri Jul 07 20:18:29 2006 +0200
> > > files:       src/kernel/la/dolfin/uBlasMatrix.h
> > > description:
> > > Use iterators in uBlasMatrix::disp().
> > > 
> > > 
> > > changeset:   2052:9ab764260e78856ffab0b4cb74f90c8815896478
> > > user:        "Anders Logg <logg@xxxxxxxxx>"
> > > date:        Fri Jul 07 19:59:38 2006 +0200
> > > files:       src/kernel/la/dolfin/uBlasMatrix.h
> > > description:
> > > Fix bug in uBlasMatrix::disp(), remove unused variable N
> > > 
> > > 
> > > -------------------------------------------------------
> > > For more details, visit http://www.fenics.org/hg/dolfin
> > > _______________________________________________
> > > DOLFIN-dev mailing list
> > > DOLFIN-dev@xxxxxxxxxx
> > > http://www.fenics.org/mailman/listinfo/dolfin-dev
> > 
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