A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3735

Date: 2013-09-02

On the difference between parallel loops and vector loops

by Robert Geva

Excerpt:

This is not a proposal, it is a clarification of existing proposals.

Some feedback regarding the loops proposed within the Cilk Plus proposal expressed interest in a loop that is both parallel and vector

Other proposals pursue the idea that an algorithm can be expressed in a way that is independent of whether it is sequential, parallel or vector, and those are chosen as “execution policy”

While all the above are useful and encouraged, this presentation suggests that single threaded vector loops are more foundational and of higher priority than the combined loops and algorithms.

The fundamental argument is that vector loops and parallel loops are mostly very different, whereas their similarities are mostly superficial