Glas List: RE: [glas] multilevel block-matrices

From: Edwards, Harold C (hcedwar_at_[hidden])
Date: 2005-03-17 11:00:47

The abstractions for vector spaces should be rich/flexible enough to
capture the needs of parallelism.  I've found it straight forward to
apply the concept of vector spaces and subspaces - e.g. the partitioning
of storage or computational responsibilities among processors is defined
by a set of subspaces, one per processor, of the vector space.

Supporting subspaces and sets of subspaces has many other applications,
e.g. defining multi-level block partitioning, defining the resizing of
vectors as a re-assignment to a different subspace.

--Carter
  

> -----Original Message-----
> From: glas-bounces_at_[hidden] 
> [mailto:glas-bounces_at_[hidden]] On Behalf Of Karl Meerbergen
> Sent: Thursday, March 17, 2005 8:36 AM
> To: Generic Linear Algorithm Software
> Subject: Re: [glas] multilevel block-matrices
> 
> On Friday 11 March 2005 17:23, plagne.laurent_at_[hidden] wrote:
> > Hi all,
> >
> 
> 
> > I wonder if this kind of feature :
> >     - multi-level blocked matrices.
> >     - optional storage policy (virtual/actual) for matrices.
> > can be of more general interest and should be considered in the GLAS
> > project ?
> 
> This is of interest. At this stage, however, we are still 
> defining the basic 
> concepts.
> 
> >
> > I also wonder about the best level for parallelism consideration :
> >    *  Computer science level : e.g. STAPL
> >    *  Linear algebra level (GLASS level ;-))
> >    *  Higher Level : e.g. FEM solvers.
> 
> Different levels may have to be considered. Parallelism was 
> one of the options 
> that was mentioned in the early requirements for GLAS. It all 
> depends where 
> the parallelism shows up in the application code: in a FE 
> code, it can appear 
> on the domain level, but it can also appear in the linear solvers.
> 
> At this stage, I would like to see the basic concepts 
> defined. There appears 
> to be a large interest to define a VectorSpace concept, so 
> let us do that 
> first and see what needs to be done next.
> 
> 
> Karl