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

Thu Oct 26 17:07:25 EDT 2017

Not on any systems acquired at NASA.    Granted we?re no longer doubling memory-per-core with each generation of our cluster, but it is still growing.   Previous machine wast 128 GB on 28 cores.  Next machine is 256 GB on 40 cores.    And this is primarily driven by the requirements of our Earth system model (including data assimilation).

We of course wish to reduce the memory footprint, as it would likely mean we could buy (and use) more cores.   But in practice it is very hard to make headway.    

> On Oct 26, 2017, at 4:27 PM, Bill Long <longb at cray.com> 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. 
> 
> Cheers,
> Bill
> 
> 
> Bill Long                                                                       longb at cray.com
> Principal Engineer, Fortran Technical Support &   voice:  651-605-9024
> Bioinformatics Software Development                      fax:  651-605-9143
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> 
> 
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