on Tue Dec 25 2012, Mathias Gaunard <mathias.gaunard-AT-ens-lyon.org> wrote:
On 24/12/12 03:54, Dave Abrahams wrote:
Well, that is one view.
It's not a matter of view. The definition of the concepts is not really subject to interpretation.
I am thinking about the abstract concepts that underly the generic programming "concepts" in that paper.
A simple change to that loop could allow a SIMD-specialized version of fill to kick in.
If we're going to specialize for SIMD anyway, then there is no point to the exercise at all.
The problem of using SIMD instructions for these operations *clearly* requires specialization no matter which approach you choose. I don't think that fact makes it a waste of time to explore different approaches to using such a specialization.
The solution you're proposing is more about extending our SIMD variants to the algorithms to work with segmented sequences, not re-using segmented iterator algorithms as defined in the paper to do SIMD.
That's a reasonable point of view.
Those are entirely two different things.
OK
I can tell you the second is not really conceptually feasible, and in the cases it is it is not a good idea. The first one is trivial and just a matter of adding the code for it, but there isn't really any incentive to do so since there are no segmented iterators in existence anywhere.
IMO given the importance of cache effects and hierarchical data structures, something like segmented iterators *should* be in existence. -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost