[mpiwg-p2p] [MPIWG Fortran] FP16 16-bit-floating-point

[Rolf Rabenseifner]

Tony,

we try to find the type names used in C and Fortran before we define
the new predefined MPI datatype handles for representing those 
language types.

Who knows, whom we can contact on the C standardization side?

Best regards
Rolf

----- Original Message -----
> From: "Anthony Skjellum" <tony at runtimecomputing.com>
> To: "MPI WG Point To Point Communications working group" <mpiwg-p2p at lists.mpi-forum.org>
> Cc: "Reinhold Bader" <Reinhold.Bader at lrz-muenchen.de>, "Atsushi Hori" <ahori at riken.jp>, "fortran standards email list
> for J3" <j3 at j3-fortran.org>, "MPI-WG Fortran working group" <mpiwg-fortran at lists.mpi-forum.org>
> Sent: Friday, June 16, 2017 2:50:00 PM
> Subject: Re: [MPIWG Fortran] [mpiwg-p2p] FP16 16-bit-floating-point

> Rolf, apart from the Fortan angle, may I strongly encourage that we adopt this
> datatype for MPI-4. It is part of real MPI codes already, but now we have to
> fake transfer datatypes as 16-bit integers or bytes... which means not really
> right if heterogeneous interoperability were to be maintained. And this is a
> canonical IEEE type now, as you note. There is also the "2 half-float" datatype
> (32-bits) at least in CUDA to be looked at; maybe ignored or maybe supported,
> but it is there too. Key to this MPI users and applications use half floats and
> 2 half-floats :-) in practice.
> 
> May I also suggest a forward look at the types in AVX-512, in case any of these
> become particularly relevant in future.
> At least 8-bit integers are conceptually new, apart from BYTE. [
> https://en.wikipedia.org/wiki/AVX-512 | https://en.wikipedia.org/wiki/AVX-512 ]
> 
> Regards,
> Tony
> 
> 
> On Fri, Jun 16, 2017 at 6:52 AM, Rolf Rabenseifner < [
> mailto:rabenseifner at hlrs.de | rabenseifner at hlrs.de ] > wrote:
> 
> 
> Hi all together,
> 
> I'm sitting in the MPI Forum Meeting and we discuss the new IEEE FP16
> datatype.
> 
> Questions to the Fortran atandardization body:
> 
> - Does the Fortran Standardization Body has already a proposal for
> the new name in Fortran for this IEEE FP16?
> 
> - Will be REAL*2 identical to IEEE FP16?
> 
> Best regards
> Rolf
> 
> --
> Dr. Rolf Rabenseifner . . . . . . . . . .. email [ mailto:rabenseifner at hlrs.de |
> rabenseifner at hlrs.de ] .
> High Performance Computing Center (HLRS) . phone [
> tel:%2B%2B49%280%29711%2F685-65530 | ++49(0)711/685-65530 ] .
> University of Stuttgart . . . . . . . . .. fax [
> tel:%2B%2B49%280%29711%20%2F%20685-65832 | ++49(0)711 / 685-65832 ] .
> Head of Dpmt Parallel Computing . . . [ http://www.hlrs.de/people/rabenseifner |
> www.hlrs.de/people/rabenseifner ] .
> Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307) .
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> 
> 
> --
> Tony Skjellum, PhD
> RunTime Computing Solutions, LLC
> [ mailto:tony at runtimecomputing.com | tony at runtimecomputing.com ]
> direct: +1-205-918-7514
> cell: +1-205-807-4968
> 
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-- 
Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de .
High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 .
University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 .
Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner .
Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307) .