[hpc-announce] CFP--Numerical Reproducibility at Exascale Workshop (NRE2019) at ISC2019

Keyrouz, Walid (Fed) walid.keyrouz at nist.gov
Wed Apr 17 17:17:38 CDT 2019

                      Call for Participation
     Numerical Reproducibility at Exascale Workshop (NRE2019)

    Where            In cooperation with ISC HPC 2019, Frankfurt, Germany
    When             TBD, but afternoon early in the conference requested
    Web              http://www.cs.fsu.edu/~nre2019
    Submit           https://easychair.org/conferences/?conf=nre2019
    Deadline         Monday, April 25, 2019
    Notifications    Monday, May 6, 2019
    Full Papers      TBD by conference publication requirements
    Organized by     Walid Keyrouz (NIST), and Michael Mascagni (FSU & NIST)

1  Overview

Experimental reproducibility is a cornerstone of the scientific
method.  As computing has grown into a powerful tool for scientific
inquiry, computational reproducibility has been one of the core
assumptions underlying scientific computing.  With "traditional"
single-core CPUs, documenting a numerical result was relatively
straightforward.  However, hardware developments over the past several
decades have made it almost impossible to ensure computational
reproducibility or to even fully document a computation without
incurring a severe loss of performance.  This loss of reproducibility
started when systems combined parallelism (e.g., clusters) with
non-determinism (e.g., single-core CPUs with out-of-order execution).
It has accelerated with recent architectural trends towards platforms
with increasingly large numbers of processing elements, namely
multicore CPUs and compute accelerators (GPUs, Intel Xeon Phi, FPGAs).

Programmers targeting these platforms rely on tools and libraries to
produce codes or execute them efficiently.  As a result, codes can run
efficiently, but have execution details that can be impossible to
predict and are often very difficult to understand after execution.
Furthermore, parallel implementations often result in code with
varying execution orders between runs, leading to non-reproducible
computations.  The underlying reasons are that (1) the hardware and
system software allocate parallel work in ways that are not always
specifiable at compile time and (2) the execution often proceeds in an
opportunistic manner with the execution order changing between runs.
As such, floating-point computations, which are not commutative and
associative, can have different execution orders and execute on
different processing elements between runs, leading to runs with
varying results as a matter of fact.  The predictability of systems is
further complicated by two issues that are becoming more critical as
systems grow in scale: (1) interconnect systems with latencies that
are often outside the control of programmers and (2) reliability as
the mean time between failure (MTBF) is now measured in hours on large
systems.  This situation seriously affects the ability to rely on
scientific computations as a metrological substitute for

2  Previous Offerings

This workshop is the fifth offering in a series that includes the
Numerical Reproducibility at Exascale (NRE) workshops (conducted at
SC15 and SC16), the panel on Reproducibility held at SC’16 (originally
a BOF at SC15), and finally Computational Reproducibility at Exascale
(CRE) held at SC17 and SC18.  All these addressed several different
issues in reproducibility that arise when computing at Exascale.

3  Workshop Scope

The workshop is meant to address issues of numerical reproducibility
as well as approaches and best practices to sharing and running code
and the reproducible dissemination of computational results.  The
workshop is meant to address the scope of the problems of
computational reproducibility in HPC in general, and those anticipated
as we scale up to Exascale machines in the next decade.  The
participants of this workshop will include government, academic, and
industry stakeholders; the goals of this workshop are to understand
the current state of the problems that arise, what work is being done
to deal with these issues, and what the community thinks the possible
approaches to these problems are.

The workshop is meant to address the scope of the problems of
numerical reproducibility in HPC in general and those anticipated as
we scale to Exascale machines in the next decade.  We initially seek
contributions of extended abstracts (two pages) in the areas of
computational reproducibility in HPC from academic, government, and
industry stakeholders.  Areas of interest include, but are not limited

• Case studies of reproducibility or the lack of it
• Reproducibility issues in current HPC
• System-level solutions
• Algorithmic solutions
• Software solutions
• Uncertainty quantification in computational reproducibility
• Fundamental numerical analysis of reproducibility
• Future prospects

4  Workshop Format

The workshop will have: (1) two plenary talks (25 min + 5 min Q&A
each), (2) four contributed talks (15 min + 5 min Q&A each), and (3) a
40-min panel discussion to summarize the problem, current research,
and prospects on long-term solutions.  The table below gives the
workshop’s schedule:

     Start         Speaker         Title
     2:00 pm       Plenary I       Thorsten Hoefler, ETH, Switzerland
     2:30 pm       Contributed 1   TBD
     2:50 pm       Contributed 2   TBD
     3:10 pm       Contributed 3   TBD
     3:30 pm       Plenary II      David R. C. Hill, ISIMA, France
     4:00 pm       Break           Food and coffee provided by conference
     4:30 pm       Contributed 4   TBD
     4:50 pm       Contributed 5   TBD
     5:10 pm       Contributed 6   TBD
     4:50 pm       Panel           Panel Discussion on Numerical Reproducibility

Papers submitted to the workshop will be reviewed.  The referees will
select the papers that will be presented in the workshop.  In
addition, a group of papers will be published in the conference
proceedings organized by ISC HPC 2019.

5  Submissions

Submissions of two page extended abstracts are sought.  The format for
the abstracts should follow the ISC HPC 2018 requirements, which are
those for Springer KLNCS proceedings.  Full papers will also follow
that format.  Abstracts are restricted to 2 pages, and full papers to
10 pages.  The abstracts are to be submitted as a PDF document using
Easychair at https://easychair.org/conferences/ ?conf=nre2019.

6  Important Dates (Mondays)

Apr. 25, 2019:  submission deadline for two page abstracts via
May 06, 2019:   notification of authors about their submissions based
                 on rejection, acceptance as a paper, acceptance as a
                 paper and presentation
TBD:            submission deadline for full papers for refereeing

7 Steering Committee

• Dong H. Ahn, Lawrence Livermore National Lab, USA
• David Bailey, UC Davis, USA
• Ronald Boisvert, NIST, USA
• François Févotte, Électricité de France, France
• David R. C. Hill, ISIMA, France
• Mike Heroux, Sandia National Laboratory, USA
• Walid Keyrouz (co-organizer), NIST, USA
• Xiaoye Sherry Li, Lawrence Berkeley National Laboratory, USA
• Thomas Ludwig, Deutsches Klimarechenzentrum, Germany
• Yaohang Li, Old Dominion University, USA
• Michael Mascagni (co-organizer), FSU/NIST, USA
• Junji Nagano, Insitute of Statistical Mathematics, Japan
• Nathalie Revol, INRIA/ENS-Lyon, France
• Siegfried Rump, University of Hamburg, Germany
• Michela Taufer, University of Tennessee, Oak Ridge

8  Contact

E-mail: numerical.reproducibility.at.nist.gov (replace ".at." by "@")



Walid Keyrouz, PhD
Research Scientist
+1 (301) 975-4031

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