Re: [boost] Accelerating algorithms with SIMD - Segmented iterators and alternatives

Subject: Re: [boost] Accelerating algorithms with SIMD - Segmented iterators and alternatives
From: David Abrahams (dave_at_[hidden])
Date: 2010-10-13 16:19:35

At Wed, 13 Oct 2010 12:18:13 -0700,
Jeffrey Lee Hellrung, Jr. wrote:
> 
> On 10/13/2010 10:50 AM, David Abrahams wrote:
> > At Wed, 13 Oct 2010 17:38:56 +0100,
> > Mathias Gaunard wrote:
> [...]
> >> Segmented iterators are only useful if the iteration of all my
> >> segments is done with the exact same logic but at different locations,
> >> since they all must have the same type. They don't allow to circumvent
> >> the problem I exposed with normal iterators at all.
> >
> > I think they do.  However, you might find that you need some dynamic
> > dispatching to get it to work.  In other words,
> >
> >    if (operating on complete segment)
> >       SIMD algorithm
> >    else
> >       elementwise algorithm
> 
> That doesn't seem any better than what I would imagine the
> range_detail::join_iterator does.  I.e., I don't see what segmented
> iteration buys us here over what I'd imagine Mathias is currently
> doing (which, I'd imagine, is some variant on a joint_iterator that
> returns aligned packets).

where's that list of algorithms again?  sort, transform, merge,
binary_search ...

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com