

Steven R. Lantz
Senior Research Associate


Cornell University Center for Advanced Computing

Welcome! Thanks for tuning in. As a computational physicist at the Cornell University Center for Advanced
Computing, I am interested in highperformance computers and how they
can be used to model, simulate, and analyze the physical world. I have a
special interest in studies of the dynamics of plasmas and fluids. My most
active research collaborations are with teams developing software to
optimize stellarator design for nuclear fusion energy (led by
Prof. David Bindel),
and to reconstruct particle tracks
in the CMS detector
at CERN (led by Prof. Peter Wittich 
feature story).
I also support the computational needs of the
Laboratory of Plasma Studies
(Prof.
Charles Seyler).
For quite a few years I worked with the
Turbulence and
Combustion Group, led by Prof. Stephen B. Pope. Other prior work
has included investigations of basic plasma instabilities in the solar
convection zone, and simulations of diffractionlimited optical imaging through
imperfect media.
In my role as technical consultant, I attempt to use my experiences on TACC's
Frontera and
Stampede2 systems,
Intelbased servers like the Hermes server at LPS,
and CAC's HPC
clusters (including the former CATS
cluster) to help others to port, run, and optimize their own applications on
highperformance parallel computers. I also contribute to training materials for
offered through the Cornell Virtual Workshop
for Frontera, Stampede2, and other NSFsupported resources. I provide specialized HPC
consulting support for CAC's
Red Cloud resources, especially
MATLAB
Parallel Server in Red Cloud.
Back in Spring 2010 I lectured on solar physics for ECE 5860,
Upper Atmospheric and Ionospheric Physics II, a course that I have taught previously
for the School of Electrical and Computer
Engineering (most recently in 2007 
flyer).
In Spring 2009, I served as the instructor for CIS
4205, Effective Use of High Performance Computing, in the
Faculty of Computing and Information
Science (flyer).
In 2017, I was elected to membership on the Graduate Faculty of Cornell University, in
the Graduate Minor Field of Computational Science and
Engineering.
Awards:
Published work:
 Latest research papers and presentations:

"Generalizing mkFit
and its Application to HLLHC," presentation at the 26th International Conference on Computing in
High Energy and Nuclear Physics (CHEP 2019), Norfolk, VA, 2023
(with G. Cerati, P. Elmer, P. Gartung, L. Giannini, M. Kortelainen, V. Krutelyov, M. Masciovecchio, T. Reid,
A. Reinsvold Hall, D. Riley, M. Tadel, E. Vourliotis, P. Wittich, and A. Yagil, on behalf of the CMS collaboration)
[arXiv]
[presentation]

"Speeding
up the CMS track reconstruction with a parallelized and vectorized Kalmanfilterbased algorithm during the LHC
Run 3," poster for the 21st International Workshop on Advanced Computing and Analysis Techniques in
Physics Research (ACAT 2022), Bari, Italy, 2022
(with S. Berkman, G. Cerati, P. Elmer, P. Gartung, L. Giannini, B. Gravelle, A. R. Hall, M. Kortelainen,
V. Krutelyov, M. Masciovecchio, K. McDermott, B. Norris, M. Reid, D. S. Riley, M. Tadel, E. Vourliotis,
B. Wang, P. Wittich, and A. Yagil, on behalf of the CMS Collaboration)
[arXiv]
[poster]

"Speeding up Particle Track
Reconstruction using a Parallel Kalman Filter Algorithm," Journal of Instrumentation 15 P09030, 2020
(with K. McDermott, M. Reid, D. Riley, P. Wittich, S. Berkman, G. Cerati, M. Kortelainen, A. Reinsvold Hall,
P. Elmer, B. Wang, L. Giannini, V. Krutelyov, M. Masciovecchio, M. Tadel, F. Wuerthwein, A. Yagil, B. Gravelle,
and B. Norris)
[doi]
[arXiv]

"Parallelization
for HEP Event Reconstruction," virtual presentation for the 40th International Conference on High Energy
Physics (ICHEP 2020), Prague, CZ, 2020
(with K. McDermott, M Reid, D. Riley, P. Wittich, S. Berkman, G. Cerati, A. Reinsvold Hall, M. Kortelainen,
M. Wang, P. Elmer, B. Wang, L. Giannini, S. Krutelyov, M. Masciovecchio, M. Tadel, F. Wuerthwein, A. Yagil,
B. Gravelle, and B. Norris)
[virtual presentation]

"Parallelizing the
unpacking and clustering of detector data for reconstruction of charged particle tracks on multicore CPUs and
manycore GPUs," Proceedings of Connecting the Dots 2020,
virtual workshop, 2020
(with G. Cerati, P. Elmer, B. Gravelle, M. Kortelainen, S. Krutelyov, M. Masciovecchio, K. McDermott,
B. Norris, M. Reid, A. Reinsvold Hall, D. Riley, M. Tadel, B. Wang, P. Wittich, F. Wuerthwein, and A. Yagil)
[virtual presentation]

"Reconstruction
of Charged Particle Tracks in Realistic Detector Geometry Using a Vectorized and Parallelized Kalman Filter
Algorithm," EPJ Web of Conferences 245, 02013, 2020,
Proceedings
of the 24th Annual International Conference on Computing in High Energy and Nuclear Physics (CHEP 2019),
Adelaide, AU, 2019
(with G. Cerati, P. Elmer, B. Gravelle, M. Kortelainen, S. Krutelyov, M. Masciovecchio, K. McDermott,
B. Norris, M. Reid, A. Reinsvold Hall, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]
[presentation]

"Speeding up Particle Track
Reconstruction using a Vectorized and Parallelized Kalman Filter Algorithm: Recent Improvements and
Applicability to the Software Trigger," Proceedings of
Connecting The Dots 2019, Valencia, ES, 2019 (with G. Cerati, P. Elmer, B. Gravelle, S. Krutelyov, M. Masciovecchio,
K. McDermott, B. Norris, A. Reinsvold Hall, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[arXiv]
[presentation]

"Parallelized KalmanFilterBased
Reconstruction of Particle Tracks on ManyCore Architectures with the CMS Detector," J. Phys.: Conf.
Ser. 1525, 012078, 2020, Proceedings
of the 19th International Workshop on Advanced Computing and Analysis Techniques in Physics
Research (ACAT 2019), SaasFee, CH, 2019 (with G. Cerati, P. Elmer, B. Gravelle, M. Kortelainen,
S. Krutelyov, M. Masciovecchio, K. McDermott, B. Norris, A. Reinsvold Hall, D. Riley, M. Tadel,
P. Wittich, F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]
[presentation]

"Parallelized
and Vectorized Tracking Using Kalman Filters with CMS Detector Geometry and Events," EPJ Web of Conferences 214, 02002, 2019,
Proceedings of the 23rd International
Conference on Computing in High Energy and Nuclear Physics (CHEP 2018), Sofia, Bulgaria, 2018
(with G. Cerati, P. Elmer, B. Gravelle, M. Kortelainen, V. Krutelyov, S. Lantz, M. Lefebvre,
M. Masciovecchio, K. McDermott, B. Norris, A. Reinsvold Hall, D. Riley, M. Tadel, P. Wittich,
F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]
[presentation]

"Parallelized KalmanFilterBased
Reconstruction of Particle Tracks with Accurate Detector Geometry," at Connecting The Dots 2018,
Seattle, WA, 2018 (with G. Cerati, P. Elmer, S. Krutelyov, M. Lefebvre, M. Masciovecchio, K. McDermott,
D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[presentation]

"Parallelized
KalmanFilterBased Reconstruction of Particle Tracks on ManyCore Architectures," J. Phys.: Conf.
Ser. 1085, 042016, 2018, Proceedings of the
18th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT
2017), Seattle, WA, 2017 (with G. Cerati, P. Elmer, S. Krutelyov, M. Lefebvre, M. Masciovecchio,
K. McDermott, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]
[presentation and paper]

"Parallelized
KalmanFilterBased Reconstruction of Particle Tracks on ManyCore Processors and GPUs," EPJ
Web of Conferences 150, 00006, 2017
Proceedings
of Connecting The Dots and Workshop on Intelligent Trackers 2017, Orsay, FR, 2017 (with G. Cerati, P. Elmer,
S. Krutelyov, M. Lefebvre, M. Masciovecchio, K. McDermott, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein,
and A. Yagil)
[doi]
[arXiv]
[presentation]

"Kalman Filter Tracking on
Parallel Architectures," J. Phys.: Conf. Ser. 898, 042051, 2017,
Proceedings of the the 22nd International
Conference on Computing in High Energy and Nuclear Physics (CHEP 2016), San Francisco, CA, 2016
(with G. Cerati, P. Elmer, S. Krutelyov, M. Lefebvre, K. McDermott, D. Riley, M. Tadel, P. Wittich,
F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]

"Reconstructing Particle Trajectories
in High Energy Physics with Xeon and Xeon Phi," at
IXPUG 2016, Argonne, IL, 2016 (with
D. Abdurachmanov, P. Elmer, G. Cerati, S. Krutelyov, M. Lefebvre, K. McDermott, D. Riley, M. Tadel,
P. Wittich, F. Wuerthwein, and A. Yagil)

"Kalman
Filter Tracking on Parallel Architectures," EPJ Web of Conferences 127, 00010,
Proceedings
of Connecting The Dots 2016, Vienna, AT, 2016 (with G. Cerati, P. Elmer, S. Krutelyov, M. Lefebvre,
K. McDermott, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]

"KalmanFilterBased Particle Tracking on
Parallel Architectures at Hadron Colliders,"
Proceedings of the
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), San Diego, CA, 2015
(with G. Cerati, M. Tadel, F. Wuerthwein, A. Yagil, K. McDermott, D. Riley, P. Wittich, and P. Elmer)
[doi]
[arXiv]

"Kalman Filter Tracking
on Parallel Architectures," J. Phys.: Conf. Ser. 664, 072008,
Proceedings of the 21st International
Conference on Computing in High Energy and Nuclear Physics (CHEP 2015), Okinawa, Japan, 2015
(with G. Cerati, P. Elmer, K. McDermott, D. Riley, M. Tadel, P. Wittich, F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]

"Traditional
Tracking with Kalman Filter on Parallel Architectures," J. Phys.: Conf. Ser. 608, 012057,
Proceedings of the 16th International
Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2014), Prague,
CZ, 2014 (with G. Cerati, P. Elmer, I. MacNeill, K. McDermott, D. Riley, M. Tadel, P. Wittich,
F. Wuerthwein, and A. Yagil)
[doi]
[arXiv]

"LargeScale Parallel
Simulations of Turbulent Combustion using Combined Dimension Reduction and Tabulation of
Chemistry," Proceedings of the Combustion Institute, 34, 205–215, 2013
(with V. Hiremath, H. Wang, and S. B. Pope)
[doi]

"ComputationallyEfficient
and Scalable Parallel Implementation of Chemistry in Simulations of Turbulent Combustion,"
Combustion and Flame, 159(10), 3096–3109, 2012 (with V. Hiremath, H. Wang, and S. B. Pope)
[doi]

"ComputationallyEfficient
Parallel Implementation of Combustion Chemistry in LES/PDF Computations," Proceedings of
the Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2011,
197206, 2011 (with V. Hiremath, H. Wang, and S. B. Pope)

"Largeeddy simulation/probability density function modeling of local extinction
and reignition in Sandia Flame E," Bulletin of the Am. Phys. Soc., 55(16), LV.0006,
at the 63rd Annual Meeting of the APS Division of Fluid Dynamics, Long Beach, CA, 2010
(with H. Wang, P. P. Popov, V. Hiremath, S. Viswanathan, and S. B. Pope)
[abstract]

"Computationally
efficient implementation of combustion chemistry in parallel PDF calculations,"
Journal of Computational Physics, 228(15), 5490–5525, 2009
(with L. Lu, Z. Ren, and S. B. Pope)
[doi]

"Investigation of strategies
for the parallel implementation of ISAT in LES/FDF/ISAT computations,"
Proceedings of the 4th Joint Meeting of the U.S. Sections of the Combustion Institute,
Philadelphia, PA, 2005 (with L. Lu, Z. Ren, V. Raman, S. B. Pope, and H. Pitsch)
[abstract]
 Virtual Workshop topics (authoring 1/year and revising 3/year, on average):

"An Introduction to Fortran Programming"
(February 2023 revision)

"Parallel I/O Libraries, Part 2"
(November 2022 revision)

"OpenMP"
(June 2022 revision)

"MPI Collective Communications"
(May 2022 revision)

"Parallel Programming Concepts and High Performance Computing"
(March 2022 revision)

"Advanced Slurm"
(August 2021)

"Understanding GPU Architecture"
(May 2021, plus December 2021 revision)

"Introduction to Advanced Cluster Architectures"
(February 2021, plus 2 revisions through March 2023)

"Parallel I/O Libraries, Part 1"
(December 2020 and November 2022 revisions)

"Getting Started on Frontera"
(August 2020, plus 2 revisions through September 2021)

"Stampede2 Environment"
(August 2019 revision, plus 2 revisions through September 2022)

"Case Study: Profiling and Optimization on Advanced Cluster Architectures"
(January 2018, plus December 2018 revision)

"Getting Started on KNL"
(November 2017, plus July 2021 revision)

"ParaView"
(September 2017 revision)

"Vectorization"
(June 2017 revision, plus 4 revisions through September 2022)

"How to Make the Most of MIC"
(April 2016)

"Python for High Performance"
(June 2015 revision)

"An Introduction to Python"
(October 2014 revision, plus 2 revisions through July 2021)

"Code Optimization"
(October 2014, plus 2 revisions through February 2019)

"Computational Steering"
(July 2014 and September 2017 revisions)

"MPI OneSided Communication"
(April 2013, plus May 2022 revision)

"Parallel I/O"
(July 2012, plus 4 revisions through October 2022)

"Scalability"
(March 2012, plus October 2014 revision)

"Hybrid Programming with OpenMP and MPI"
(June 2011, plus 3 revisions through January 2023)

"MPI Advanced Topics"
(May 2011, plus 2 revisions through May 2022)

Much of the Glossary

Numerous contributions to
"MPI Basics" and
"MPI PointtoPoint Communication,"
 Technical papers and presentations:

"Performance Case Study: the mkFit Particle Tracking Code," presentation at the
Fourth Computational and Data Science school for High Energy Physics
(CoDaSHEP 2022), Princeton, NJ, Aug. 2, 2022

"Introduction
to Performance Tuning & Optimization Tools," presentation at the Fourth
Computational and Data Science school for High Energy Physics (CoDaSHEP 2022), Princeton, NJ, Aug. 2, 2022

"Vector
Parallelism on MultiCore Processors," presentation at the Fourth
Computational and Data Science school for High Energy Physics (CoDaSHEP 2022), Princeton, NJ, Aug. 12, 2022

"What
Every Computational Physicist Should Know About Computer Architecture," presentation at the
Fourth Computational and Data Science school for High Energy Physics
(CoDaSHEP 2022), Princeton, NJ, Aug. 1, 2022 (with I. Cosden)

"Vector
Parallelism on MultiCore Processors," presentation at the Third
Computational and Data Science school for High Energy Physics (CoDaSHEP 2019), Princeton, NJ, July 25, 2019

"XSEDE Advanced Scientific Computing in Python, Parts 1 and 2," presentations for the
NASA DIRECTSTEM
20182019 PreTrainee Workshops at Cal State LA, Los Angeles, CA, Feb. 23 and Mar. 2, 2019 (with R. Camacho
Barranco and C. Myers)

"Vector
Parallelism for KalmanFilterBased Particle Tracking on Multi and ManyCore Processors," presentation at the
Second Computational and Data Science school for High
Energy Physics (CoDaSHEP 2018), Princeton, NJ, July 26, 2018 (with M. Tadel)

"Introduction to Python 3
and Jupyter Notebooks," halfday tutorial at PEARC18,
Pittsburgh, PA, July 23, 2018 (with K. Cahill and A. Gomez)

"Vector
Parallelism for KalmanFilterBased Particle Tracking on Multi and ManyCore Processors," twopart presentation
at the First Computational and Data Science school for High
Energy Physics (CoDaSHEP), Princeton, NJ, July 13, 2017 (with M. Tadel)

"Introduction to Python," halfday tutorial at PEARC17,
New Orleans, LA, July 10, 2017 (with K. Cahill and A. Gomez)

"Red Cloud and the MATLAB Distributed Computing
Server (MDCS)," presentation and demo for the Scientific Software
Club at Cornell, May 8, 2017

"Introduction to Knights Landing (KNL),"
presentation and training session for the Scientific Software Club
at Cornell, Dec. 5, 2016

"Introduction to Python," halfday tutorial at XSEDE16,
Miami, FL, July 18, 2016 (with K. Cahill and A. Gomez)

"High Performance Computing in the
Manycore Era: Challenges for Applications,"
CACM Seminar
at the Rochester Institute of Technology, Nov. 17, 2015

"Enhancing the Experimental
'MATLAB on the TeraGrid' Resource," poster at TeraGrid '11, Salt Lake City, UT, 2011 (with D. Lifka,
E. Chen, L. Walle, S. Mehringer, S. Clark and P. Meunier)

"Running Parallel Simulations
and Enabling Science Gateways with the NSF MATLAB Experimental Computing Resource at
Cornell," tutorial at SC10, New Orleans, LA, 2010 (with S. Mehringer and S. Clark)
[abstract]

"The Ranger Virtual Workshop,"
Proceedings of TeraGrid '08,
Las Vegas, NV, 2008 (with S. Mehringer, N. Woody, A. Dolgert, D. Fuller, D. Stanzione, and J. Zollweg)
[2011 update]
 Papers deriving and applying a model for anelastic MHD convection, published
in The Astrophysical Journal and its Supplement Series:

"Anelastic Magnetohydrodynamic Equations for Modeling Solar and Stellar
Convection Zones," ApJS 121(1), 247–264, 1999 (with Y. Fan)
[doi]

"Twodimensional Simulations of Buoyantly Rising, Interacting Magnetic Flux
Tubes," ApJ 493(1), 480–493, 1998 (with Y. Fan and E. G. Zweibel)
[doi]

"Magnetoconvection Dynamics in a Stratified Layer. I. 2D Simulations and
Visualization," ApJ 441(2), 903–924, 1995
(with R. N. Sudan) [doi]

"Magnetoconvection Dynamics in a Stratified Layer. II. A Loworder Model
of the Tilting Instability," ApJ 441(2),
925–941, 1995 [doi]
 My vita lists other publications and many of
my recent activities.
Undergraduate researchers:
Clark Amerault spent part of his senior year at Cornell (Summer and Fall 1999)
working with me on simulations of solar supergranulation. He produced a
report on our
project featuring many nice MPEG visualizations. You may also want to visit
a miniposter
with highlights from the video, "Bifurcations in 2D Rotating Magnetoconvection",
which made its debut in November, 1998 at the APS Div. of Fluid Dynamics meeting
in Philadelphia, PA. The visualizations in it were created with the help of the
following undergraduates:
 Adrienne Gvozdich, Cornell University (Fall 1998)
 Michael Katz, Cornell University (Fall 1998)
 Oleg Abramov, Clarkson University (Summer 1998)
Adrienne and Michael put together the final version of the video, building on
the work of Oleg and several other prior students listed below (Bryan, Cooke,
Rudin, Sanders, Wright). This line of research has largely been carried out in
conjunction with SPUR, the erstwhile Supercomputing Program for Undergraduate
Research at the Cornell Theory Center (aka CTC, back when that was our name).
A complete roster of my students from the SPUR era, along with links
to their final project reports, follows.

Modeling Solar Supergranulation, 1997 SPUR project with Justin Boland,
University of Texas at Dallas

Visualization Tools and Parallel Speedup, 1996–97 academic year projects
with Howard Sanders, Cornell University

Dynamics of Solar Magnetoconvection, 1996 SPUR project with Cynthia
Rudin, SUNY at Buffalo

Dynamics of Solar Convection, 1995 SPUR project with Jason Cooke
and Kevin Wright, SUNY at Stony Brook and Montana State University
(respectively)

Rotating Thermal Convection in Astrophysics, 1994 SPUR project
with David Bryan, Richard Stockton College of New Jersey

Modeling and Visualization of Magnetohydrodynamics, 1992 SPUR project with
Michael Wiltberger, Clarkson University. (Published in CTC's 1993 online
brochure, Discovery: Insights Through Advanced Computing, under the
title, "The Simmering Sun.")
Some favorite links:
Computing
 UNIX Tutorial for Beginners
Solar physics
 Solar images at
SDAC
 NASA/Marshall Solar Physics
 Ulysses
 Science  Primary Mission Results
 Coronal mass ejection (CME) movies from SOHO/LASCO:
 LASCOC2 movie (222K mpeg) of
April 7, 1997 fullhalo coronal mass ejection (CME) event
 LASCOC3 movie (760K mpeg) of
Dec. 22–27, 1997, with CME's, the galactic center, and a sungrazing comet
 A Virtual Tour of the Sun
 The Sun from
The Nine Planets Solar System Tour
(for a while it was also known as eightplanets.org, after Pluto was demoted!)
 Sun from
Views of the Solar System
 Education at HAO
Space physics
 Space Weather Conditions and
3Day Forecast
 Current Solar Wind
Conditions from Rice Univ.
 Spaceweather.com
 Auroral Activity Observation
Network
 The Aurora Page at MTU
 Red Sprites and Blue Jets
Astronomy
 Transits of
Venus
 Stars and
Constellations
 Naked Eye Observations
 A 3yearold's perspective on the dilemma of
daytime vs. nighttime astronomy
 A 4yearold's speculation on an alternate
terrestrial gravity field
 A 7yearold's hypothesis on the consequences
of alternate gravity
Pretty old stuff (but maybe still interesting?):
Last updated on 1/23/24 by Steve Lantz (steve.lantz ~at~ cornell.edu)