Re: [boost] [fusion] segmented sequences and algorithms

From: Joel de Guzman (joel_at_[hidden])
Date: 2006-10-06 02:11:28

Eric Niebler wrote:
> Chris Weed wrote:
>  > On 10/5/06, Eric Niebler <eric_at_[hidden]> wrote:
>  >> The idea of segmented fusion sequences and algorithms has been discussed
>  >> here several times, and Joel has made some reference to some earlier
>  >> work I did in this area. I had done some tests at the time that
>  >> suggested that a segmented sequences and algorithms could significantly
>  >> outperform nonsegmented variants Fusion currently uses. Per Joel's
>  >> suggestion, I went ahead and checked my code into CVS HEAD. All
>  >> segmented-specific code is quarantined in separate ext_ directories.
>  >>
> 
> <snip>
> 
>> Hi,
>> This sounds cool. These seems similar to having iteration on rows of an image.
>> Is it possible to iterate from segment to segment at the same position
>> of each segment.
>> Chris
>>
> 
> Not in general. Not all the segments of a sequence necessarily have the 
> same number of elements. Some, in fact, may be empty.

However, since we can also detect at compile time the sizes of
sequences, we can enforce that requirement. I think the zip_view
does that already.

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net