Re: [ublas] rvalue reference and move

Subject: Re: [ublas] rvalue reference and move
From: David Bellot (david.bellot_at_[hidden])
Date: 2010-05-26 07:33:42

Hi Nasos,

can you post the code on the list directly, so that we can all benefit from
it.
My only concern is the support of old compilers. Let's have an experimental
branch for that and see what we can do.
But it sounds a good idea.

Cheers,
David

On Sat, May 22, 2010 at 20:22, Michael Chen <sth4nth_at_[hidden]> wrote:

> Nasos,
> Cool, I'd like to try your code. where can I get it?
> Best,
> Mo
>
> On Sun, May 23, 2010 at 1:52 AM, Nasos Iliopoulos <nasos_i_at_[hidden]>
> wrote:
> > Mo,
> > that's why I was talking about expression expansion in the post. This
> could
> > be performed on a dynamic manner, rather than a static manner (as
> > expressions are currently implemented). Of course this is a big paradigm
> > shift and unless it is thoroughly investigated ublas should probably stay
> > away from it. Anyway, if somebody is interested I think I have some code
> > lying around playing with r-value stuff (it needs a compiler that
> supports
> > the new standard).
> >
> > Best
> > Nasos.
> >
> >> Date: Sun, 23 May 2010 01:40:48 +0800
> >> From: sth4nth_at_[hidden]
> >> To: ublas_at_[hidden]
> >> Subject: Re: [ublas] rvalue reference and move
> >>
> >> Nasos,
> >> The example showed in that link does not entirely eliminate
> >> temporaries. Consider the expression
> >> x = (a+b)+(c+d);
> >> here we construct two temporaries and one is wasted.
> >>
> >> However, I don't think we should re-implement the operators, since
> >> those are already handled by expression template. I think only move
> >> constructor and move assignment operator should be added for
> >> container of uBlas.
> >>
> >> Best,
> >> Mo
> >>
> >> On Sat, May 22, 2010 at 10:56 PM, Nasos Iliopoulos <nasos_i_at_[hidden]
> >
> >> wrote:
> >> > Mo,
> >> > in your compile options use BOOST_UBLAS_MOVE_SEMANTICS.
> >> >
> >> > (i.e. in gcc that would be -DBOOST_UBLAS_MOVE_SEMANTICS)
> >> >
> >> > I would like to make a couple of changes in the bounded types and push
> >> > the
> >> > idea to make the move_semantics default, as it seems all compilers
> >> > support
> >> > copy elision and even if they don't there is no penalty.
> >> >
> >> > see also:
> >> >
> http://www.boost.org/doc/libs/1_43_0/libs/numeric/ublas/doc/options.htm
> >> >
> >> > There had been some discussion in the past and I see that with the new
> >> > standard we will be able to go even further in totally eliminating
> >> > temporaries.
> >> > Take a look at this also:
> >> > http://cpp-next.com/archive/2009/09/making-your-next-move/
> >> >
> >> > Best
> >> > Nasos
> >> >
> >> >> Date: Sat, 22 May 2010 15:39:08 +0800
> >> >> From: sth4nth_at_[hidden]
> >> >> To: ublas_at_[hidden]
> >> >> Subject: [ublas] rvalue reference and move
> >> >>
> >> >> Since gcc 4.4 4.5 and VC2010 all support the rvalue reference, I
> think
> >> >> it will be beneficial to utilize this feature to implement the move
> >> >> semantic for those containers of uBlas. Is there any plan for this or
> >> >> anyone doing this?
> >> >>
> >> >> Regards,
> >> >> Mo
> >> >> _______________________________________________
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> >> >> ublas_at_[hidden]
> >> >> http://lists.boost.org/mailman/listinfo.cgi/ublas
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> >> >
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-- 
David Bellot, PhD
david.bellot_at_[hidden]
http://david.bellot.free.fr