[Swift-devel] playing with array closing.

[Mihael Hategan]

On Tue, 2007-11-20 at 16:41 +0000, Ben Clifford wrote: 
> On Tue, 20 Nov 2007, Mihael Hategan wrote:
> 
> > I thought you can reorder them, but it may be difficult if a single
> > statement writes to multiple arrays (such as the foreach).
> 
> Source text order is a linear order; it is possible to flatten any DAG 
> into a linear order, but loses some of the information in the DAG.
> 
> I thought a bit before about trying to reorder dataset delcarations in the 
> compiled code with respect to execution statements, to try to get mapper 
> parameters computed before they are used; I think what happened was that 
> this introduced unnecessary serialisation (though maybe its possible with 
> a suitably large mix of parallel and sequential blocks).

It isn't in the general case.

The "most relevant link" is a book, but see
http://dx.doi.org/10.1016/0304-3975(94)00272-X for some info.

Basically parallel (independent) and sequential (linear) blocks are not
sufficient to provide a decomposition of an arbitrary dag.

The article talks about graphs with no primitive structures (those that
can be decomposed using only seq/par).

>