(j3.2006) (SC22WG5.5383) [ukfortran] Straw vote on draft DTS

Malcolm Cohen malcolm
Sat Dec 6 21:42:17 EST 2014

> Please answer the following question "Is N2033 ready for forwarding to
> SC22 as the DTS?" in one of these ways.
> 1) Yes.
> 2) Yes, but I recommend the following changes.
> 3) No, for the following reasons.
> 4) Abstain.

NO, for the following reasons.

I agree with Robert Corbett's vote.

I am somewhat taken aback that we've suddenly added this new concept 
(stalled images) with far-reaching effects (and more proposed in other 
comments) at the last minute.

It needs to be clear that it is possible to implement the "reliability" 
(failed/stalled/whatever image) features efficiently on a variety of 
architectures.  It should not require incompatible changes to an existing 
coarray implementation (which the current draft certainly seems to do).  I 
have no problem with some "bells and whistles" potentially requiring extra 
work, but a reasonably effective subset needs to be workable without heroic 
efforts, and without affecting programs that do not use the feature.

Additional minor comment:
Re finalization, I agree with Tobias Burnus' comments that it would be good 
for this to be spelled out in detail for CO_BROADCAST and CO_REDUCE.  For 
the latter it should say that the result of applying the function is 
finalized, including the final function application, (the latter is as if 
the output variable were assigned an expression that is the last function 
reference).  It should, I think, also be stated that the finalizations of 
the intermediate function results are done on the image that actually 
invoked the function, so that any deallocations are handled by the image 
that did the allocations.

............................Malcolm Cohen, NAG Oxford/Tokyo.

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