Subject: Re: [ublas] rvalue reference and move
From: Nasos Iliopoulos (nasos_i_at_[hidden])
Date: 2010-05-22 13:52:30
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).
> Date: Sun, 23 May 2010 01:40:48 +0800
> From: sth4nth_at_[hidden]
> To: ublas_at_[hidden]
> Subject: Re: [ublas] rvalue reference and move
> 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.
> 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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