The SCaLeS Report Opportunities and Needs in Basic Energy Sciences

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The SCaLeS ReportOpportunities and Needs in
Basic Energy Sciences

• Thom H. Dunning, Jr.
• Joint Institute for Computational Sciences
• University of Tennessee Oak Ridge National
  Laboratory
• Oak Ridge, Tennessee

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Outline of Presentation

• Background
• Trends Computing Technologies
• Trends Scientific Applications
• Scientific Opportunities
• SCaLeS Workshop
• SCaLeS Report
• Reports, Editors, and Process
• Recommendations

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Background Trends Computing Technologies

• Computers
• Microprocessor performance continuing to double
  every 18-24 months, but
• increasing mismatch with memory subsystem
  performance
• increasing mismatch with communications subsystem
  performance
• Storage
• Disk storage capacity doubling every year, but
• data transfer rates increasing only modestly
• Communications Fabric
• Increasing performance, but
• increasing mismatch with performance of
  computational nodes
• increasing mismatch with needed I/O transfer rates

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Background Trends Scientific Applications

• Computational Models
• Continually refining existing models and creating
  new models
• Multi-physics and multi-scale problems pose
  challenges
• Parallel Computing
• Increasing use of parallelism
• Most codes scale to 10s of processors, a few to
  1-2,000 processors, but almost none to 10,000
  processors
• Mathematical Techniques
• New approaches hold great promise
• Linear scaling reducing the growth rate in
  computational cost with increasing molecule size

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Scientific Opportunities

• Combustion Science
• Reacting chemical flows
• Autoignition
• Molecular Science
• Chemical reactivity (combustion, catalysis)
• Heavy-element chemistry
• Materials Science
• Materials design
• Multiscale materials modeling
• Nanoscience
• Self-assembly
• Simulation of nano-devices

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SCaLeS Workshop

• Date June 23-24, 2003
• Location Arlington, Virginia
• Organizer D. Keyes, Columbia University
• Goal to assess the major opportunities and
  challenges facing computational science in areas
  of strategic importance to the Office of Science
• Participants 300 scientists and engineers from
  academia, national laboratories, federal agencies
  and other institutions

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SCaLeS Report

• Editors
• David Keyes, Editor-in-Chief
• Phil Colella, LBNL (mathematics) Thom Dunning,
  UT/ORNL (science) Bill Gropp, ANL (computer
  science)
• Topical Editors
• Chemistry R. Harrison, ORNL T. Windus, PNNL
• Combustion J. Bell, LBNL L. Rahn, SNL
• Materials Science F. Gygi, LLNL M. Stocks, ORNL
• Nanoscience P. Cummings, Vanderbilt L-W. Wang,
  LBNL
• Process
• Preliminary topical reports compiled from
  Workshop notes
• Reports iterated with Workshop participants plus
  others

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SCaLeS Report
(contd)

• Two Volumes
• Volume 1. Summary and recommendations
• Available for download http//www.pnl.gov/scales/
  
• Volume 2. Detailed discussion of scientific
  opportunities and challenges
• Available early next year

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SciDAC Successful Prototype to Build On
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SCaLeS ReportRecommendations

• Investments in Foundations of Computational
  Modeling and Simulation
• 1. Computational Science
• 5. Basic Theory and Mathematical Algorithms
• 6. Recruit Computational Scientists
• Investments in Hardware and Software
  Infrastructure
• 2. Multidisciplinary Teams
• 4. Computing Systems and Scientific Applications
  Software
• 3. Capability and Capacity Computing
• 8. New Computer Architectures for Scientific
  Computing
• Investments in Networking and Collaboration
  Technologies
• 7. Network Infrastructure and Software to
  Support Distributed Computing and Data Resources
  and Scientific Teams

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SCaLeS ReportRecommendations Foundations

• Recommendation 1
• Major new investments in computational science
  are needed in all of the mission areas of DOEs
  Office of Science, so that the United States is
  the first, or among the first, to capture the new
  opportunities presented by the continuing
  advances in computing power.
• Recommendation 5
• Additional investments in hardware facilities
  and software infrastructure should be accompanied
  by sustained collateral investments in algorithm
  research and theoretical development.
• Recommendation 6
• Computational scientists of all types should be
  proactively recruited with improved reward
  structures and opportunities as early as possible
  in the educational process so that the number of
  trained computational science professionals is
  sufficient to meet present and future demands.

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Investments in Computational ScienceAdvances in
Molecular Simulations

• Bond energies critical for describing many
  chemical phenomena
• Accuracy of calculated bond energies increased
  dramatically from 1970-2000
• Due to advances in
• Theoretical methodology
• Computational techniques
• Computing technology

100
l
l
Error (kcal/mol)
10
l
l
1
1970
1980
1990
2000
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SCaLeS ReportRecommendations Infrastructure

• Recommendation 2
• Multidisciplinary teams, with carefully selected
  leadership, should be assembled to provide the
  broad range of expertise needed to address the
  intellectual challenges associated with
  translating advances in science, mathematics and
  computer science into simulations that can take
  full advantage of advanced computers.
• Recommendation 4
• Investment in hardware facilities should be
  accompanied by sustained collateral investment in
  the software infrastructure for them. The
  efficient use of expensive computational
  facilities and the data they produce depends
  directly upon multiple layers of systems software
  and scientific software which, together with the
  hardware, are the engines of scientific discovery
  

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Developing New Simulation Capabilities
Problem with Mathematical Model?
Theory (mathematical model)
Computer Science
Applied Mathematics
Problem with Computational Method?
Computational Science (scientific codes)
Basic Math Algorithms
Computer Systems Software
Computational Predictions
Inadequate
Experiment?
Performance?
YES
NO
New Tool for Scientific Discovery
Adequate
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SCaLeS ReportRecommendations Infrastructure

• Recommendation 3
• Extensive investments in new computational
  facilities is strongly recommended, New
  facilities should strike a balance between
  capability computing for those heroic
  simulations that cannot be performed in any
  other way, and capacity computing for
  production simulations that contribute to the
  steady stream of progress.
• Recommendation 8
• Federal investments in innovative, high-risk
  computer architectures that are well suited to
  scientific and engineering simulations is both
  appropriate and needed to complement commercial
  research and development. The commercial
  computing marketplace is no longer effectively
  driven by the needs of computational science.

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Branscomb ReportFrom Desktop to Teraflop
Frontier Computers
Capability Computing
High-end Capacity Computing
Supercomputers
Increasing Cost per Flop
Increasing Capability
Mid-range Parallel Computers and Clusters
Workgroup Capacity Computing
Personal Computers and Workstations
Personal Computing
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Parallel Simulations Hard vs Soft Scaling
Hard Scaling near linear speed-up
independent of problem size uncommon
increasing problem size
Speed-up
Soft Scaling decreasing speed-up with
constant problem size increase problem size to
maintain scaling but cost of calculation can
increase more rapidly than that gained from
increased scalability common
Number of Processors
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SCaLeS ReportRecommendations Networks and
Collabs

• Recommendation 7
• Sustained investments must be made in network
  infrastructure for access and resource sharing,
  as well as in the software needed to support
  collaboration among distributed teams of
  scientists, recognizing that the best possible
  science teams will be widely separated
  geographically and that researchers will
  generally not be co-located with facilities and
  data.

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Distributed Teams and Resources
High-speed networks plus grid and collaboratory
software are needed to connect researchers with
each other and with computing and data resources.
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Advances in Computer Technology
The rising tide of change shows no respect for
the established order. Those who are unwilling
or unable to adapt in response to this profound
movement not only lose access to the
opportunities that the information technology
revolution is creating, they risk being rendered
obsolete by smarter, more agile, or more daring
competitors.
Jack J. Dongarra University of Tennessee