Subject: Re: Comments on sequence and storage associated COMMON

From: Rob Schreiber <[email-masked]>
Date: Thu, 23 Jul 92 10:42:59 PDT

On sequence and storage association, From John Merlin:

	   ****  In fact, such data will have to be communicated or   *****
	   ****  remapped virtually every time they're referenced!!!  *****

That is what Rick Swift has been claiming, but Andy and Tom still claim it is
important to allow users to specify replication of a linear object.

	However, for maximum efficiency on vector machines the array was
	flattened-out wherever possible, always across procedure boundaries, 
	often to a one-dimensional vector.  

But there are other good uses in F77, too.   It was the best way to pass a
subarray to a subroutine.

	Perhaps a usage survey would be very valuable, especially as a lot of 
	codes will be ported from vector machines to HPF, I imagine.

We did one, and there are users who are afraid to give it up all at once,
since there codes that make heavy use of it.

	(4) Finally, if the concensus is to stick with the current proposal for
	sequence and storage association for common blocks, I implore you to 
	change the default to NO_SEQUENCE_ASSOCIATION and NO_STORAGE_ASSOCIATION.
	That way, if I do the 'right thing' and declare my common block
	data the same way in every program unit I can distribute it without 
	pain.  I concur with Richard Schapiro, in that I view common block 
	data as simply "a funny way of passing arguments to subprograms".
	I want to be able to distribute my arrays the same whether they're 
	dummy parameters, local or global---without extra horrible directives.
	Let those who use sequence and storage association have the pain of
	all that typing! :-)

That is what we intend.

	In fact, it's arguable that the only directives should be for 
	SEQUENCE_ASSOCATION and STORAGE_ASSOCIATION---there shouldn't be a need 
	for special directives if these features aren't used.  Also, why are 
	there two directives---is any different action taken if there is only 
	sequence or only storage assocation but not both?  If not, you could 
	merge the directives into one:

		!HPF$ SEQUENCE_ASSOCIATION_AND_OR_STORAGE_ASSOCATION

It will probably be       CHPF$ SEQUENCE /FOO/