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ASCeNews Quarterly Newsletter - March/June 2011

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Issue 16
  March/June 2011

The Meisner Minute

Editorial by Bob Meisner

Greetings from
HQ.  It has been six months since our
last newsletter, not only because the newsletter editor Reeta Garber retired,
but also because we moved to a new web site.

During that time
we received our FY2011 budget and completed planning for this year’s
deliverables, signed a memorandum of understanding (MOU) with the Office of Science
to work jointly towards exascale, delivered the final configuration of Cielo
and signed a contract to deliver over 6 petaFLOPS of capacity computing under
the Tri-lab Capacity Computing, or TLCC-2, project.  I spent much of my time working with all three
labs in identifying the National Security Enterprise drivers pushing us into
exascale computing regimes.

For well over a year, we’ve been active in
the DOE’s exascale initiative. We have formally joined with the Office of
Science in a cooperative effort to define a unified program for the DOE through
the MOU I mentioned above.  The ASC
program has a clear mission need for exascale-level computing, but we recognize
that there are significant technical and administrative hurdles that we need to
overcome, and our partnership with other major players will help us achieve our
ends. We share the technical challenges, but our mission drivers differ.

Our need for exascale arises from our
commitment to “deliver confidence” to support national security decisions.  This commitment is captured nicely by this
statement: “By 2025 provide the
predictive simulation capabilities necessary to understand an aging US
stockpile and assess the performance of foreign nuclear devices.
” This
short statement encapsulates four main points that define our drivers in an
unclassified manner.  First, 2025 is a
time when stockpile advice will be given by designers and engineers one to two
generations beyond those with test experience. 
Second, we must equip these future generations with simulation
capabilities largely devoid of empiricism. This predictive capability must be
sufficient to judge a stockpile with components older than those tested
underground.  And, finally, the
predictive tools we develop must be applied to assessing devices for which we
lack test experience.

During the past
six months, there have also been staff changes in the ASC Program. We were sad
to lose Sander Lee to his pursuit of other professional interests outside supercomputing,
and we wish him well.  Paul Henning from
LANL has agreed to come to HQ for three months to fill in for Sander while we
look for his replacement. As you read this, the Dans will have departed the
Forrestal building. Dan Segalman has already returned to SNL-Livermore, while
Dan Nikkel returns to LLNL after completing his final assignment assembling the
“Need for Exascale” story. The Physical Engineering and Modeling program
welcomes Jason Pruet as its new federal lead. Jason divides his time between
ASC and the Science Campaign as we work to break down “cylinders-of-excellence”
between programs. Finally, we are fortunate to have Mark Anderson on a
year-long detail from LANL to finish his work on the V&V strategy and help
us with the Defense Applications and Modeling program.

In closing allow
me to reiterate that your job by 2025 is to deliver technical confidence by
providing the predictive simulation capabilities necessary to understand an
aging US stockpile and to assess the performance of foreign nuclear
devices.  Nobody does it better than you.

 Sergey—It was a pleasure seeing you at SC10 last year.  Happy

Cielo Upgrade Positions ASC Well for CCC2

Cielo is a petascale resource for conducting NNSA weapons simulations
in the 2011–2015 timeframe. Cielo provides a production, classified
computational resource. It is located at Los Alamos National Laboratory and is
operated by ACES: The New Mexico Alliance for Computing at Extreme Scale, a collaboration
between Los Alamos and Sandia national laboratories.

During May 2011,
the Cielo system was upgraded from 1.03 petaFLOPS (72 cabinets) to 1.37 petaFLOPS
(96 cabinets). After the
hardware upgrade, the Cielo operating system was also upgraded.
Panasas file system software upgrades are part of the
upgrade plans and are ongoing in preparation for Capability Computing Campaign
2 (CCC2). Users from all three laboratories — Los Alamos, Lawrence Livermore,
and Sandia national laboratories — are using Cielo for CCC1 applications work
until CCC2 begins in July 2011.


Replacing the Purple supercomputer, Cielo is the new
NNSA ASC production, classified computational resource for 2011–2015. Cielo is
over 13 times the size of Purple; it began providing capability-computing cycles in
February 2011.


Green Computing at LANL

Power Use/Utilization
Effectiveness (PUE) close to Industry’s best-in-class metric

collected in April 2011 show that the ASC Facility Operations and User Support
Program at LANL has significantly improved energy efficiency of operations in
the Metropolis Center for Modeling and Simulation. The Center houses Cielo,
TLCC, and Roadrunner systems. This improvement is addressing DOE Order 430.2B Departmental Energy, Renewable Energy and
Transportation Management
. The DOE Order calls for energy reduction in the
entire DOE by 30% by 2015. Energy reduction actions also enable LANL to meet
DOE Order 450.1A, Environmental
Protection Program

A new
automated power and temperature-metering system installed in the Center has
contributed to achieving an industry-standard power use/utilization
effectiveness (PUE) rating of 1.3, which is close to Industry’s best-in-class
metric of 1.2. While allowing data collection for building a baseline, the system
also gives the ability to systematically turn on and off facility equipment
based on changing computer-room platform and supporting infrastructure
requirements. For example, the addition of 24 racks to Cielo recently increased
the system size by .33 petaflops (PFs) from 1.03 PFs to 1.37PFs.


Sandia’s Quantified Margins and Uncertainties Assessment of W80 Abnormal
Mechanical Nuclear Safety

In an assessment funded by the Advanced
Simulation and Computing (ASC) Program, a W80 system model is being used to
quantify the margins and uncertainties (QMU) of nuclear safety issues in
abnormal mechanical environments such as handling drop accidents.  Underpinning this project are the uncertainty
quantification methods and computational tools developed by the ASC program,
including SIERRA solid mechanics codes to perform the simulations. Uncertainties
in the system model, which are prohibitively expensive to determine exclusively
from comparisons with full system experiments, were derived in part by
propagating uncertainties determined from model comparisons with subsystem and
material characterization tests (such as the notched tension model shown below)
up to the integrated system level.

In addition, novel mesh-independent methods
for modeling failure propagation and material softening, recently incorporated
in the SIERRA solid mechanics codes, are being tested for their effectiveness
and efficiency in addressing long-standing computational issues bearing on this
and other systems in abnormal mechanical environments.  The project has undergone peer review by a
panel of experts in a series of evaluations, most recently in late 2010. The
project is supporting the 2011 and 2012 W80 Annual Assessment Reports.

Codes Assess National Ignition Facility Risks

Lawrence Livermore
scientists leveraged advanced physics models in the modern ASC codes to make
assessments of the risk to National Ignition Facility (NIF) chamber optics and
diagnostics caused by debris generated during laser-driven materials science
experiments. High-resolution 2D and 3D simulations were used in the decision
making process to determine if it was safe to proceed with NIF experiments.

Debris risk
assessment for the Material Strength Drive (HEDS) experiments was performed
using a combination of simulation tools, including ALE3D and ParaDyn. The ARES
code was used to evaluate the debris risk for a radiative supernova
hydrodynamics experiment conducted in collaboration with the University of


Simulation Supporting Component Design

simulations using Sandia’s coupled physics SIERRA Engineering Mechanics
framework have provided valuable insight during the design of the Direct
Optical Initiation (DOI) firing set. Previous testing, under the Common
Adaptable System Architecture (CASA) program, revealed that flash-lamp
assemblies could be damaged in high-level shock environments.

The goal of this
work was to apply SIERRA Mechanics tools to understand the source of the
observed damage and thereby help guide the design of the current DOI flash-lamp
assembly. Application of high-level shock environments in a mechanical
computational model of the CASA flash-lamp assembly (Figure 1) showed critical
stress regions (shown as red in Figure 2) consistent with the location of fractures
observed after testing. The analysis suggested that residual stresses from
glass manufacturing and flash-lamp packaging are both critical factors in
determining ultimate flash-lamp environmental response.

fig 1

challenges include the design of glass-to-metal seals, managing mismatches in
thermal expansion properties of the various materials, and providing robust
means for flash-lamp packaging that would protect glass components from
expected shock and vibration environments. These results provide the DOI
flash-lamp team with early input to identify robust manufacturing processes and
to guide mechanical design decisions.


ParaDiS Code Extended for Face-Centered Cubic Systems

Lawrence Livermore scientists recently extended the ParaDiS
code capability to simulate dislocation responses in face-centered cubic (FCC
systems), thus enabling prediction capabilities under extreme conditions for a
wide range of materials. 

Previously, the code was used for only body-centered cubic
(BCC) metals predictions, where simulations were run on ASC’s BlueGene/L
supercomputer to demonstrate ParaDiS’s new capability as part of a multiscale
modeling program by constructing predictive constitutive models.  

Sixteen elemental solids exhibit the FCC crystal structure
at ambient conditions as well as common engineering materials such as aluminum
alloys and austenitic stainless steels. The new capability in ParaDiS will
enable LLNL to predict the dynamic strength of common structural
materials. A small-scale simulation is currently underway to investigate
the relationship between the stress-strain response and its underlying
microstructure in single crystal FCC copper.

green box






A snapshot of
dislocation structure at the end of an early simulation stage. Many portions of
the cell are occupied by dislocation tangles separated by empty space in
between, where this type of microstructure can lead to significant increase in
material strength







Themis Approach Provides Remote Ensemble Analysis

Modeling and
simulation are central to stockpile verification and validation.  Groups of related ASC simulation runs
(ensembles) are used to evaluate the sensitivity of computer models to
variations in material properties or other input parameters.  Sensitivity analysis examines how variation
in simulation outputs can be mapped to, or understood in relation to,
differences in the inputs.  Given the
scale of ensemble data, movement of ensembles off the High Performance
Computing (HPC) systems where they are generated to separate systems for
analysis is impractical.

In response,
Sandia National Laboratories is developing Themis, a Web-based approach (see
illustration), for conducting remote sensitivity analysis on ensemble data
using a three-tiered architecture.  The
first tier consists of the big data or computationally expensive parallel
analysis operations that must remain on the HPC.  The second tier provides database storage and
tracking of previous analysis results, integrated with a web server and access
controls to authenticate users and user groups. The third tier provides
interactive visualization and remote exploration of the analysis results
through a standard Web browser. 

screen shot


  The illustration shows Themis
analysis of car data correlating physical characteristics (inputs) with
performance data (outputs).
Bar charts show
high-level correlations between all inputs (top half labeled in green) and all
outputs (bottom half labeled in purple). Positive correlation values are upward
red bars, while negative values are downward blue bars. The length of each bar
indicates its magnitude/relative importance. Opposite colors between inputs and
outputs represent inverse relationships, whereas same colors show positive
relationships.  The scatter plot shows
how well individual cars match the high-level correlations, with the best
matches appearing closest to the diagonal.
Cars are color-coded by their individual MPG values (from blue to red,
with red high), where MPG has been selected in the linked table of raw values


For ASC-sized data ensembles, we expect remote
analysis and visualization to become standard, as data sizes continue to
increase. The tiered architecture that underlies Themis provides a scalable
mechanism for supporting many use cases – from collaborative analysis to
domain-specific, specialized applications. Themis serves as a concrete example
of this architecture, providing researchers and analysts an opportunity to
experiment with the algorithmic, visual, and cognitive challenges of ensemble


LLNL Researchers Find
Way to Mitigate Traumatic Brain Injury in Study for Joint IED Defeat

Researchers at
Lawrence Livermore National Laboratory (LLNL) have found that soldiers using
military helmets one size larger and with thicker pads could reduce the
severity of traumatic brain injury (TBI) from blunt and ballistic impacts.
Their results came after a one-year study funded by the U.S. Army and the Joint
IED Defeat Organization (JIEDDO) to compare the effectiveness of various
military and football helmet pads in mitigating the severity of impacts.

Moss and King
used a combination of experiments and computational simulations to study the
response of the various pad systems to battlefield-relevant impacts to gain an understanding
of how helmet pads provide protection against these impacts.

The findings have
been presented to the Program Executive Office (PEO) Soldier, which is directed
by Brig. Gen. Peter Fuller and is the U.S. Army acquisition agency responsible
for everything a soldier wears or carries.

mike king




LLNL mechanical engineer Mike King (left) and physicist Willy Moss watch a compression test of a helmet pad. The pair has found a simple way to potentially reduce the severity of traumatic brain injury from blunt and ballistic impacts 






To learn more, see the ABC TV (KGO) report.


Roadrunner Open Science in Nature

As the first petascale
supercomputer, Roadrunner brought fame in computing technology and scientific
discovery and recognition to Los Alamos National Laboratory (LANL). It has also
brought success to research using the state-of-the-art plasma simulation code
VPIC. One example is the study of magnetic reconnection, a process thought to play an important role
in a diverse range of applications including solar flares, geomagnetic
substorms, magnetic fusion devices, and a wide variety of astrophysical
problems. An article describing simulation results and its effect on the
research is published in Nature Physics.*
The petascale supercomputer has enabled a series of three-dimensional
simulations using over 1012 computational particles, nearly 103
larger than previous two-dimensional studies.

blue boxA simulation of three-dimensional reconnection showing
interacting flux ropes forming across the reconnection layer. Some sample
magnetic field lines are shown in yellow and cutting planes along the perimeter
also show current density.


*W. Daughton, et al., "Role of electron physics in the
development of turbulent magnetic reconnection in collisionless plasmas," Nature Physics,
published online 10 April 2011 (


Modeling Rotation of a Galaxy Wins Supercomputing
Challenge Top Prize

A program for middle- and high-school students that encompasses the
school year, the New Mexico Supercomputing Challenge is an opportunity to work
on the most powerful computers in the world.

In April 2011, students, teachers, and volunteer judges conducted
project evaluations that culminated in an awards ceremony. Los Alamos Middle
School student Cole Kendrick won several prizes, including the top prize, for
his research project in which he developed a computer program to model the
rotation of a galaxy including dark matter.

Evoking memories of the Roadrunner Universe open-science project to
shake down the Roadrunner supercomputer in 2009, Kendrick's project was set up
to find out how dark matter affects rotational curves in galaxies and how
accurately this effect could be modeled. Kendrick wanted to find out what
happens when dark matter and galaxy masses are changed and whether this method
would work for different galaxies. In addition to the top prize, he also
received the Crowd Favorite Award and the Best Use of Visualization and
Parallel Processing awards from the New Mexico Institute of Mining and
Technology’s Computer Science and Engineering Department. To read more about
the Challenge, visit

top prizestudentsstudents 3

Computing Milestones Showcased at LANL’s Museum

For decades, Los
Alamos National Laboratory has been synonymous with supercomputing, achieving a
number of milestones along the way.

Those milestones
and more are showcased in a supercomputing exhibit called “The Road to
Roadrunner and Beyond” at LANL’s Bradbury Science Museum (
Visitors at the museum get a comprehensive look at supercomputing from its
origins up to and beyond Roadrunner, the world’s first computer to operate at
speeds exceeding one petaflop — 1 million billion calculations per second. The
updated exhibit includes interactive displays, artifacts from early computers
like the FERMIAC mechanical computer, vacuum tubes from the MANIAC computer,
and unique IBM cell blades from Roadrunner. To see a video about the exhibit,
Updating the exhibit was made possible by a grant from the Institute of
Electrical and Electronics Engineers (IEEE).

ribbon cutting

ceremony kicks off “The Road to Roadrunner and Beyond” exhibit on May 19, 2011.
Left to right: David Israelevitz, Research Engineer; Dr. Gordon W. Day, IEEE
President Elect; Andrew White, LANL Deputy Associate Director; and Linda Deck,
Museum Director. Photo by Sandra Valdez, LANL.


ASC Salutes















Douglas (Doug)
Doerfler is a Principal Member of Technical Staff in the Scalable Computer
Architectures organization at Sandia National Laboratories.  He has been with the ASC Program since 2000
working in the Computational Systems and Software Environment (CSSE) program
element, formerly known as Simulation and Computer Science.

In his present
position, Doug is the principal system architect
for the Cielo project. Cielo — a petascale supercomputer — has replaced
Lawrence Livermore National Laboratory’s Purple machine as the ASC Program’s
production capability computing platform. The development of the Cielo system
is the first and most visible activity for the Los Alamos National Laboratory
(LANL)/Sandia Alliance for Computing at Extreme Scale (ACES) — a collaboration
established by a May 2008 MOU signed by then Sandia Director Tom Hunter and
LANL Director, Michael Anastasio. As the Cielo system architect, Doug has
served as the technical lead for the Request For Proposals and led the
development of the acceptance criteria. He has had a key role in managing the
integration and deployment of Cielo, which includes the successful completion
of a very visible LANL/Sandia Level 2 programmatic milestone, “Platform
Integration Readiness.”

For Cielo, Doug
has assumed and addressed numerous technical and programmatic responsibilities
associated with managing Cielo’s deployment
across two laboratories — a first in which two DOE/NNSA laboratories have
jointly deployed a supercomputer.  “The
Cielo project has been my highest profile assignment and has been a good match
for my skill set: technical judgment, leadership and management,” says
Doug.  “And it has been my most satisfying
project. I’ve really enjoyed having a key role in the ACES relationship with
LANL, and even though Cielo is sited at Los Alamos, Sandia continues to
demonstrate a high level of computer architecture and platform leadership and
is able to continue to provide impact in the capability computing area for

Much in Doug’s
background has prepared him for his current assignment and this subsequent
recognition. Upon joining the ASC Program in 2000, Doug worked on the
Computational Plan (CPlant) project. This project
was an early ASC effort to explore using commodity hardware and open source
software for large-scale scientific computing, i.e. an early instance of what
we refer today as cluster computing. The CPlant program deployed several clusters
at Sandia. When Doug came to the ASC program, one of his first impacts was to
develop an integration and test methodology for the Antarctica cluster — the
largest and final CPlant deployment at over 2000 nodes. This effort was
rewarded with a promotion to management for Doug. In addition to managing
CPlant his group was also responsible for maintaining one of the ASC Program’s
first supercomputers, ASCI Red. The builder’s (Intel) contract had expired and
Sandia had assumed the operational management for the program. Later, he was
also part of the ASC’s Red Storm supercomputer acquisition team.

Much farther in the past as a graduate student, Doug,
worked on a Sandia contract, looking at low-power data acquisition techniques
for unattended ground sensors. This led to a job at Sandia, hiring on in the
summer of 1985. “My first project was working with a team to develop a
perimeter security system for the Air Force. I developed the control software
that collected data from sensors placed around the perimeter of international
Air Force bases. This system was installed on several bases worldwide. In 1988
I transferred to a group that was developing automatic target recognition (ATR)
techniques and systems for the Army, and eventually the Air Force. I led the
development of several real-time ATR systems, the highlight being a deployment
on one of the Air Force's Joint STARS aircraft, a collaborative effort among
Sandia, Northrop Grumman and the Air Force. These prior projects provided me
with an introduction to high performance computing (HPC) at the embedded level
and I wanted to better understand the technologies and challenges of
large-scale computing, and the ASC program was a perfect fit.  I transferred to Sandia’s Computing and
Research Center in 2000 and began my third ‘career’ at Sandia working on the a
series of large-scale machines: CPlant, Red Storm, TLCC, Red Sky, Cielo.”

Doug also
participates in DOE workshops, such as the current exascale workshops hosted by
the NNSA and the Office of Science, and represents Sandia and ASC at numerous
conferences and meetings with industry, academia and other government
organizations.  His
primary research interest is in area of performance analysis of
HPC platforms and technologies and has published several conference papers and
journal articles. Most recently he co-authored a paper published in the IEEE
International Parallel and Distributed Processing Symposium Workshop on
Large-Scale Parallel Processing. This paper, "Investigating the Impact of
the Cielo Cray XE6 Architecture on Scientific Application Codes,” was also
selected for publication in a special issue of Parallel Processing Letters Journal. Co-authors are Courtenay Vaughan, Mahesh Rajan, and Richard
F. Barrett.  He is also co-author
of a paper titled, "Application-Driven Acceptance of Cielo, an XE6
Petascale Capability Platform," published at the 2011 Cray User Group
(CUG) meeting describing the methodology that was developed to use NNSA
applications as a primary acceptance criterion for Cielo. Co-authors included
Mahesh Rajan, Cindy Nuss (Cray), Cornell Wright (LANL), and Tom Spelce (LLNL).

Los Alamos’
Manuel Vigil (Cielo Project Manager) has this to say about his Sandia

“It is a pleasure
working with Doug on the Cielo Project. As the principal system architect for
Cielo, Doug has provided outstanding leadership and guidance to the multi-site
technical team on Cielo system integration. His deep understanding of
supercomputing issues has allowed him to provide leadership to both Cray and
Panasas, as well as the technical experts from both Sandia and Los Alamos. One
key area where Doug has demonstrated outstanding leadership is his working with
Sandia, LLNL, and LANL applications personnel to interact with Cray in
demonstrating outstanding application performance on Cielo. I highly value and
appreciate Doug's leadership and contributions to the Cielo project.”

Outside work,
Doug enjoys “going to movies with my family, motorcycling, bicycling and
keeping my house from falling apart.”


ASC Relevant Research


Sandia National Laboratories

Citations for Publications in 2011

  1. Ahn,
    T., Dechev, D., Lin, H., Adalsteinsson, H., Janssen, C.  (2011). “Evaluating Performance Optimizations
    of Large-Scale Genomic Sequence Search Applications Using SST/macro,” Proceedings, 1st International Conference on
    Simulation and Modeling Methodologies, Technologies and Applications, SIMULTECH
    Noordwijkerhout, The Netherlands.

  2. Brightwell,
    R. (2011). "Why Nobody Should Care About Operating Systems for Exascale,
    Keynote Address," Proceedings,
    International Workshop on Runtime and Operating Systems for Supercomputers
    Tucson, Arizona.

  3. Clay,
    R. (2011). “The Challenges of Programming Exascale Class Machines, Keynote
    Address,” Proceedings, 25th
    IEEE International Parallel & Distributed Processing Symposium, 12th
    International Workshop on Parallel and Distributed Scientific and Engineering
    Anchorage, Alaska.

  4. Feldman,
    S., LaBorde, P., Dechev, D. (2011). “Facilitating Efficient Parallelization of
    Information Storage and Retrieval on Large Data Sets,” Proceedings, 25th ACM International Conference on Supercomputing (ICS
    , Tucson, AZ.

  5. Doerfler,
    D., Rajan, M., Nuss, C., Wright, C., Spelce, T., (2011). “Application-Driven
    Acceptance of Cielo, an XE6 Petascale Capability Platform,” Proceedings, Cray User Group Meeting, Fairbanks,

  6. Doerfler,
    D., Vigil, M., Dosanjh, S., Morrison, J., (2011). “The Cielo Petascale
    Capability Supercomputer,” Proceedings,
    Cray User Group Meeting,
    Fairbanks, Alaska.

  7. Fabian,
    N., (2011). “Scalability of Paraview’s Coprocessing Capability,” Proceedings, Cray User Group Meeting, Fairbanks,

  8. Kelly,
    S., Klundt, R., Laros, J. (2011). “Shared Libraries on a Capability Class
    Computer,” Proceedings, Cray User Group
    Fairbanks, Alaska.

  9. Lange,
    J., Pedretti, K., Dinda, P., Bridges, P., Bae, C., Soltero, P., Merritt, A.
    (2011). "Minimal-overhead Virtualization of a Large Scale
    Supercomputer," Proceedings, ACM
    SIGPLAN/SIGOPS International Conference on Virtual Execution Environments (VEE)
    Newport Beach, California.

  10. Olivier, S., Porterfield, A.,
    Wheeler, K., Prins, J. (2011). "Scheduling Task Parallelism on
    Multi-Socket Multicore Systems," Proceedings,
    International Conference on Supercomputing

  11. Pébay, P., Thompson, D., Bennett,
    J., Mascarenhas, A. (2011). “Design and Performance of a Scalable, Parallel Statistics
    Toolkit,” Proceedings, 25th
    IEEE International Parallel & Distributed Processing Symposium, 12th
    International Workshop on Parallel and Distributed Scientific and Engineering
    Anchorage, Alaska.

  12. Taerat, N., Brandt, J., Gentile, A.,
    Wong, M., Leangsuksun, C. (2011). “Baler: Deterministic, Lossless Log Message
    Clustering Tool,” Proceedings,
    International Supercomputing Conference,
    Hamburg, Germany.

  13. Thompson, D., Pébay, P. (2011) “A
    Method for Inferring Conditional Stochastic 
    Failure Rates from the Time-history of Observed Failures,"  Processings
    of Reliability, Stress Analysis, and Failure Prevention Conference
    ,  Washington, DC.

  14. Vaughan, C. T. (2011). “Application
    Characteristics and Performance on a Cray XE6,” Proceedings, Cray User Group Meeting, Fairbanks, Alaska.

  15. Vaughan, C., Rajan, M., Barrett, R.
    F., Doerfler, D., Pedretti, K., (2011). “Investigating the Impact of the Cielo
    Cray XE6 Architecture on Scientific Application Codes”, Proceedings, IEEE International Parallel and Distributed Processing
    Symposium, Workshop on Large-Scale Parallel Processing (LSPP)
    , Anchorage,

  16. Wheeler, K., Stark, D., Murphy, R.,
    Chamberlain, B. (2011). "The Chapel Tasking Layer over Qthreads," Proceedings, Cray User Group Meeting,
    Fairbanks, Alaska.

for Publications in 2010

[Additions to those in Issue 15.]

  1. Brightwell,
    R., Barrett, B., Hemmert, K. Scott, Underwood, Keith D. (2010). Challenges for
    High-Performance Networking for Exascale Computing, Proceedings, International Conference on Computer Communication
    , Zurich, Switzerland.

  2. Dechev,
    D., Pirkelbauer, P., Stroustrup, B. (2010). “Understanding and Effectively
    Preventing the ABA Problem in Descriptor-based Lock-free Designs,” Proceedings, 13th IEEE International
    Symposium on Object/component/service-oriented Real-time Distributed Computing
    (IEEE ISORC 2010)
    , Carmona, Spain.

  3. Merritt,
    A., Pedretti, K. (2010). "Techniques for Managing Data Distribution in
    NUMA Systems, " Poster, ACM/IEEE
    Conference on High Performance Networking and Computing (SC10)
    , New
    Orleans, Louisiana.

  4. Murphy,
    R., Wheeler, K., Barrett, B., Ang, J. (2010). "Introducing the Graph
    500," Proceedings, Cray User Group
    , Edinburgh, Scotland.

  5. Pedretti,
    K., Bridges, P., (2010). "Opportunities for Leveraging OS Virtualization
    in High-End Supercomputing," Workshop
    on Micro Architectural Support for Virtualization, Data Center Computing, and
    Clouds (MASVDC)
    , Atlanta, Georgia.

  6. Rajan,
    M., Doerfler, D., (2010) “HPC application performance and scaling: understanding
    trends and future challenges with application benchmarks on past, present and
    future Tri-Lab computing systems," Proceedings,
    8th International Conference of Numerical Analysis and Applied Mathematics
    Rhodes, Greece.

  7. Rajan,
    M., Doerfler, D., Vaughan, C., Epperson, M., Ogden, J., (2010) “Application
    Performance on the Tri-Lab Linux Capacity Cluster - TLCC," International Journal of Distributed Systems
    and Technologies
    , Volume 1, Issue 2 (pages 23-39).

  8. Ulmer, C., Bayer, G., Choe, Y., Roe, D.
    (2010). "Exploring Data Warehouse Appliances for Mesh Analysis
    Applications," Proceedings, Hawaii
    International Conference on System Sciences
    , Koloa, Hawaii.

  9. Vaughan,
    C., Doerfler, D., (2010) “Analyzing Multicore Characteristics for a Suite of
    Applications on an XT5 System," Proceedings,
    Cray Users Group Meeting
    , Edinburgh, Scotland.


for Publications in 2009

[Additions to those in Issue 15.]

  1. Doerfler,
    D.W., (2009). “Analyzing the Application Performance Impact of Using High-Speed
    Inter-Socket Communication Networks," Invited Presentation, Workshop on The Influcence of I/O on
    Microprocessor Architecture (IOM-2009)
    , Raleigh, NC.

  2. Martin,
    B.J., Leiker, A.J., Laros, J.H., Doerfler, D.W., (2009). “Performance Analysis
    of the SiCortex SC092," (** Best Student Paper) Proceedings, The 10th LCI International Conference on
    High-Performance Clustered Computing
    , Boulder, CO.

  3. Moreland,
    K. (2009).  "Diverging Color Maps
    for Scientific Visualization," Proceedings,
    5th International Symposium on Visual Computing
    , Las Vegas, Nevada.

  4. Rajan,
    M., Doerfler, D., Vaughan, C., (2009). “"Red Storm / Cray XT4: A Superior
    Architecture for Scalability ," Proceedings,
    Cray Users Group Meeting
    , Atlanta, Georgia.



Los Alamos National Laboratory

Citations for Publications in 2011

  1. Booth, T.E. (2011). "An
    Alternative Monte Carlo Approach to the Thermal Radiative Transfer
    Problem," Journal of Computational
    , Vol. 230, No. 4, pp, 1516-1527.

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  6. Kamm, J.R., Shashkov, M.J., Fung,
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  7. Lipnikov, K., Manzini, G., Brezzi,
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  8. Lipnikov,
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  9. McClarren,
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  10. Wollaber, A.B.,Larsen, E.W. (2011). "A
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