(j3.2006) [Fwd: Fortran 2008 query]

[Van Snyder]

On Thu, 2017-10-26 at 20:27 +0000, Bill Long wrote:

> > On Oct 26, 2017, at 2:58 PM, Van Snyder <Van.Snyder at jpl.nasa.gov>
> wrote:
> > 
> >> 
> >> We could say that it is a processor-dependent value greater or
> equal to 1023.
> > 
> > Ridiculously small.  Why design a language for machines that were
> obsolete twenty years ago?  We should be designing for the future, not
> the past.
> 
> You mean the real future where the amount of memory/core continues to
> decline, and where broadcasting the executable out to all the
> participating processors becomes slower as the size of the executable
> increases (because of initialized arrays)?    The better option in
> cases like this is usually to read the data in from an unformatted
> file when the program starts.  Maybe just to image 1 and broadcast it
> from there. 


The systems we use have had memory per core increase by a factor of four
during the last decade.

Memory per core might decline, but memory per node, i.e., memory
directly addressable by a core without going through a transport
network, probably won't.  Is the lexer phase of the compiler going to be
a coarray program?  Maybe so, but will it use all the cores on the
processor?  Would every image need to have a buffer for the entire
statement?  Is per-image memory going to be limited by (total memory per
node) / (cores per image)?

Just because it's possible to read data from a file doesn't mean that's
always the best solution (unless you myopically make it the only
solution).  Are all the intrinsic function routines (and other math
software) that use Pad? approximations going to read their constants
from files?  I don't think so.  There is still a need for programs to
have constants.  The standard ought not to judge how many are
"reasonable" for every program.


> 
> Cheers,
> Bill
> 
> 
> 
> Bill Long                                                                       longb at cray.com
> Principal Engineer, Fortran Technical Support &   voice:  651-605-9024
> Bioinformatics Software Development                      fax:  651-605-9143
> Cray Inc./ 2131 Lindau Lane/  Suite 1000/  Bloomington, MN  55425
> 
> 


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