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Subject: Re: [ublas] Assignement operation proposal.
From: Riccardo Rossi (rrossi_at_[hidden])
Date: 2010-03-23 03:41:01


Hi,

jus
-
________________________________________________________________
Riccardo Rossi, Ph.D, Civil Engineer
member of the Kratos Group: kratos.cimne.upc.es
Centro Internacional de Métodos Numéricos en Ingeniería (CIMNE)
Universidad Politécnica de Cataluña (UPC)
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08034 Barcelona, España
Tel. (+34) 93 401 5696
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On Mon, 2010-03-22 at 20:18 -0400, Nasos Iliopoulos wrote:
> Hi Gunter,
> > I opened a new ticket to track progress.
> > https://svn.boost.org/trac/boost/ticket/4034
>
> I will do some more introspective implementations (this is already the
> 4th or 5th iteration) and will see what version I will finally choose
> (indexes vs iterators). Both will be included only if the same
> functionallity is achieved (unless list members think otherwise).
>
> > it should be a separate header, maybe it is then included from
> > matrix/vector.hpp
>
> ok, will stick with that. Only concern here is whether project(..)
> << ....; can be implemented without touching range and slice classes.
> I guess this can be decided later.
>
> > I don't know if "assigner.hpp" is a good name, but I could not find a
> > better one, yet.
> A better name is indeed needed.
>
> > (if BOOST_UBLAS_NO_ELEMENT_PROXIES is not defined then a proxy is
> > returned instead of the real element and the insert is performed
> during
> > the destruction of the proxy - obviously this makes things only
> worse)
>
> I will try to follow an implementation that I feel is safe to release
> sometime in the future. Since my experience with sparse types is
> limited, any contribution is highly desirable.
>
> > Do you think it is possible to use triples (i,j,value) to fill a
> sparse
> > matrix, e.g. like
> >
> > cm << sparse_element(0,0,1.0), sparse_element(1,3,2.0) ;
>
> yes this can be implemented. Actually, the non_vector free function
> provides a type that is used to move the internal indexing to a new
> position, hence having effectively the functionallity of the above. I
> believe though that there is value in both interfaces, so will provide
> them both. Is there any reason that your example should be restricted
> to sparse types? Maybe something like that? : cm << set(1, 3,
> 2.0), ... ;
>
> I also consider providing classes so that more elegant filling is
> possible. i.e.:
> an operator move(dx,dy) that will move dx rows and dy columns, an
> operator move_to(x, y) that will move to specific locations, as well
> as enable matrix assignments:
>
> matrix<double> big(100,100);
> matrix<double> small(10,10);
>
> big<< move_to(45,45), small, move(0,10), small;
>
> Finally do you all prefer operator << or maybe operator <<= (so that
> we avoid ambiquities with streaming and also have a chance to let
> templates resolve some type combinations?)
>
> Best
> Nasos
>
>
>
>
>
>
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