Subject: hpff-distribute: Re: HPF reduce directive

From: Fabien COELHO <[email-masked]>
Date: Tue, 2 Jan 96 19:43:42 +0100

---------------------------------------------------------------------------
[email-masked] is a mailing list for discussion of data
distribution in High Performance Fortran.  Instructions for adding or
deleting yourself from this list appear at the bottom of this message.
---------------------------------------------------------------------------

Hi Chuck,

> Actually, the mailing list that is discussing REDUCE is hpff-task.

Sorry for the mis-posting, and thanks for the pointer.

About independent:

> I'll comment that I generally like the "external" syntax, modulo a
> couple syntax nits (for example, INDEPEDENT does not name the loop index,

Oops... Your're right (for sure:-). 

I noticed the syntax from early versions of the HPF document (0.2 for
instance) and never notice ever since that it was dropped out!

I parse it with my compiler (as well as the implicite one). I found it
quite convenient for loop nests (the inner loop indexes being implicitely
private...) 

chpf$ independent(i,j)     
      do i = ...
         do j = ...
            ...
         enddo
      enddo

instead of

chpf$ independent, new(j)  
      do i = ...
chpf$    independent
         do j = ...
            ...
         enddo
      enddo

But this is just a matter of syntactic sugar. And verbosity.

> and doesn't apply to nested loops.)

Do you mean that my inner loop cannot be tagged as independent?
Because it is not perfectly nested?

I have not seen such a restriction in HPF 1.0 (or it is not listed in the
constraint list?). I cannot see any rational for it. The compiler is not
required to execute the loop in parallel, it's just a matter of asserting
some semantical property of a piece of code, in my understanding.

BTW, Happy new year!

Fabien.

--
Fabien COELHO __ http://www.cri.ensmp.fr/~coelho __ [email-masked]
  CRI, ENSMP, 35, rue Saint Honoré, 77305 Fontainebleau Cedex, France
     phone: 33 1 64 69 {voice: 48 52, fax: 47 09, standard: 47 08}
       ________  All opinions expressed here are mine  ________
---------------------------------------------------------------------------
To (un)subscribe to this list, send mail to
[email-masked].
Leave the subject line blank, and in the body put the line
(un)subscribe <email-address>
---------------------------------------------------------------------------