Idiomatic way of writing nested loops?

[Russel Winder via Digitalmars-d-learn]

On Tue, 2017-07-18 at 08:41 +0000, Anton Fediushin via Digitalmars-d-learn
wrote:
> On Tuesday, 18 July 2017 at 03:36:04 UTC, Nicholas Wilson wrote:
> > With regards to parallel, only use it on the outermost loop. 
> > Assuming you have more items in the outermost loop than you do 
> > threads parallelising more than one loop won't net you any 
> > speed.
> 
> Thank you! Yes, `parallel` runs only 4 threads on my machine, so 
> there is no reason to use it in nested loops.

But how many processors, cache sizes, memory speed, etc, etc, etc. The only
way of knowing what the fastest performance is is to try some things and get
some performance data. Even then the result only applies to that data on
that computer.

This is the sort of situation where philosophising about performance often
ends up with totally the wrong code.

-- 
Russel.
=============================================================================
Dr Russel Winder     t:+44 20 7585 2200   voip:sip:
russel.winder at ekiga.net
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