Andrew Myers
Computer Systems Engineer, Applied Mathematics and Computational Research Division
Contact Information
Andrew Myers
MS 50A3111
Lawrence Berkeley National Lab
1 Cyclotron Rd.
Berkeley, CA 94720
5104866900 (fax)
ATMyers@lbl.gov


Affiliation and Research Interests
I am a member of the Center for Computational
Sciences and Engineering (CCSE) at the Lawrence Berkeley National Laboratory (LBNL).
My current research focuses on the design and implementation of scalable parallel algorithms for conducting particle and particlemesh simulations on current and upcoming supercomputing architectures, particularly in the context of adaptive mesh refinement. These algorithms have applications to the modelling of, for example, largescale structure formation in cosmology, plasma acceleration in particle accelerators, and the solids phase in multiphase flow problems.
More generally, I am interested in parallel algorithms for scientific computing (particularly for GPU platforms), particle methods, and the visualization and analysis of large simulation datasets.
Much of my work is open source and can be followed on my Github page.
Current Projects
Particles in AMReX
I am the lead developer of the
particle library in AMReX,
a software framework for building massively parallel
blockstructured adaptive mesh refinement (AMR) applications that is supported by the
Exascale Computing Project (ECP). Particles are used in some capacity by most of the AMReX
application codes, including six of the ECP application development projects.
In AMReX, we are particularly interested in particles that live on and interact with a
constantlychanging hierarchy of refinement patches, which adds an additional layer of
complication to the underyling data structures. AMReX provides methods for handling the
MPI communication of particle data, including both redistribution and halo exchange, as well as
implementations of several common operations used in particle applications, such as neighbor
list construction, particlemesh deposition and interpolation, reductions, etc.
Much of my recent work has focused on reworking the particle data structures and algorithms for hybrid
CPU/GPU platforms, such as OLCF's Summit machine.
AMReX application codes involving significant particle
work have been demonstrated to scale well up to the full machine, and have demonstrated good speedups
over CPUonly platforms.

Plasma and laser wakefield acceleration with WarpX
I am
also a member of the ECPfunded WarpX project, which is collaboration
between CCSE and the
Accelerator Modelling
group at LBNL, Livermore Lab, and
the Stanford Linear Accelerator Center. The goal of this project is to build a new simulation
tool for studying plasma and laser driven wakefield acceleration, a process by which charged
particles are accelerated over much shorter distances than in conventional accelerators. The hope
is that, by harnessing the power of future exascale computers, WarpX can aid in the design of smaller,
less costly particle accelerators.
WarpX is a relativistic, electromagnetic ParticleinCell code that includes several advanced features, such as
spectral Maxwell solvers, perfectlymatched absorbing layers, mesh refinement, ionization, and the ability to
operate in a boosted reference frame. Along with MFIXExa,
it is one of the primary drivers of development for the AMReX particle library.

Previous Work
I completed my PhD in Physics at the University of California
at Berkeley in September 2013, working with Richard Klein and Christopher
McKee on the topics of highmass star formation and the interstellar medium.
Later, I was a postdoctoral researcher in the Applied Numerical Algorithms
Group at LBNL, where I worked on various mathematical topics related to the
convergence of particleincell schemes for VlasovPoisson problems. You can
read about this work in my publications below. Finally, I have also been
active in the opensource scientific Python community, in particular with the
yt project,
and still retain interests in largescale scientific visualization and data
analysis.
Publications
 Bruce J. Palmer, Ann S. Almgren, Connah G.M. Johnson, Andrew T Myers, and William R. Cannon,
3D Modeling of Nutrient Transport in Growing Cell Colonies,
submitted for publication.
 Luca Fedeli, Axel Huebl, France BoillodCerneux, Thomas Clark, Kevin Gott, Conrad Hillairet,
Stephan Jaure, Adrien Leblanc, Rémi Lehe, Andrew Myers, Christelle Piechurski, Mitsuhisa Sato,
Neil Zaïm, Weiqun Zhang, JeanLuc Vay, Henri Vincenti,
Pushing the frontier in the design of laserbased electron accelerators with groundbreaking
meshrefined particleincell simulations on exascaleclass supercomputers,
SC '22: Proceedings of the International Conference on High Performance Computing, Networking, Storage and Analysis,
November 2022, Article No.: 3, Pages 1–12
[doi]
 Severin Diederichs, Carlo Benedetti, Axel Huebl, Remi Lehe, Andrew Myers,
Alexander Sinn, JeanLuc Vay, Weiqun Zhang, Maxence Thevenet,
HiPACE++: a portable, 3D quasistatic ParticleinCell code,
Computer Physics Communications, 278, 108421, 2022.
[link][arXiv]
 Jean Sexton, Zarija Lukic, Ann Almgren, Chris Daley, Brian Friesen, Andrew Myers, and Weiqun Zhang,
Nyx: A Massively Parallel AMR Code for Computational Cosmology,
Journal of Open Source Software, 6(63), 3068, 2021.
[doi]
 L. Fedeli, A. SainteMarie, N. Zaim, M. Thevenet, J. L. Vay, A. Myers, F. Quere, and H. Vincenti,
Probing strongfield QED with Dopplerboosted petawattclass lasers,
accepted by Physical Review Letters, May 10, 2021,
[PRL]
 Sherwood Richers, Don E. Willcox, Nicole M. Ford, and Andrew Myers,
Particleincell simulation of the neutrino fast flavor instability, Physical Review D,
April 20, 2021,
[doi]
 Jordan Musser, Ann S Almgren, William D Fullmer, Oscar Antepara, John B Bell,
Johannes Blaschke, Kevin Gott, Andrew Myers, Roberto Porcu, Deepak Rangarajan,
Michele Rosso, Weiqun Zhang, and Madhava Syamlal,
MFIX:Exa: A Path Towards Exascale CFDDEM Simulations,
The International Journal of High Performance Computing Applications, April 16, 2021.
[IJHPCA]
[doi]
 Weiqun Zhang, Andrew Myers, Kevin Gott, Ann Almgren and John Bell,
AMReX: BlockStructured Adaptive Mesh Refinement for Multiphysics Applications,
The International Journal of High Performance Computing Applications, June 12, 2021.
[IJHPCA]
[doi]
 JL Vay, Ann Almgren, LD Amorim, John Bell, L Fedeli, L Ge, K Gott, DP Grote, M Hogan,
A Huebl, R Jambunathan, R Lehe, A Myers, C Ng, M Rowan, O Shapoval,
M Thevenet, H Vincenti, E Yang, N Zaim, W Zhang, Y Zhao and E Zoni,
Modeling of a chain of three plasma accelerator stages with the
WarpX electromagnetic PIC code on GPUs,
Physics of Plasmas, 28(2), 2021.
[doi]
 Andrew Myers, Ann Almgren, Diana Almorim, John Bell, Luca Fedeli, Lixin Ge, Kevin Gott, David Grote,
Mark Hogan, Axel Huebl, Revathi Jambunathan, Remi Lehe, Cho Ng, Michael Rowan, Olga Shapoval,
Maxence Thevenet, JeanLuc Vay, Henri Vincenti, Eloise Yang, Neil Zaim, Weiqun Zhang, Yin Zhao,
Edoardo Zoni,
Porting WarpX to GPUaccelerated platforms,
accepted by Parallel Computing, 2021.
[arxiv]
 Y. Zhao, R. Lehe, A. Myers, M. Thevenet, A. Huebl, C. B. Schroeder, and J.L. Vay,
Modeling of emittance growth due to Coulomb collisions in plasmabased accelerators,
Physics of Plasmas, October, 2020.
[doi]
 W Zhang, A Almgren, V Beckner, J Bell, J Blashke, C Chan, M Day, B Friesen, K Gott, D Graves, M Katz, A Myers, T Nguyen, A Nonaka, M Rosso, S Williams, M Zingale,
AMReX: a framework for blockstructured adaptive mesh refinement,
Journal of Open Source Software, May 2019
 B Loring, A Myers, D Camp, EW Bethel,
Pythonbased in situ analysis and visualization
Proceedings of the Workshop on In Situ Infrastructures for Enabling ExtremeScale Analysis and Visualization  ISAV 18, ACM Press, 2018
 JL Vay, A Almgren, J Bell, L Ge, DP Grote, M Hogan, O Kononenko, R Lehe, A Myers, C Ng, J Park, R Ryne, O Shapoval, M Thevenet, W Zhang,
WarpX: A new exascale computing platform for beamplasma simulations,
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018, 909:476479
 M Krumholz, A Myers, R Klein, C McKee,
What Physics Determines the Peak of the IMF? Insights from the Structure of Cores in RadiationMagnetohydrodynamic Simulations,
MNRAS, May 19, 2016
 A Myers, P Colella, B Van Straalen,
A 4thOrder ParticleinCell Method with PhaseSpace Remapping for the VlasovPoisson Equation,
SIAM Journal on Scientific Computing, Volume 39, No 3, pp. B467B485, May 9, 2017
 A Myers, P Colella, B Van Straalen,
The Convergence of ParticleinCell Schemes for Cosmological Dark Matter Simulations,
The Astrophysical Journal, Volume 816, Issue 2, article id. 56, 2016
 A Myers, C McKee, PS Li,
The CH+ abundance in turbulent, diffuse molecular clouds,
Monthly Notices of the Royal Astronomical Society, Volume 453, Issue 3, p.27472758, November 1, 2015
 A Myers, R Klein, M Krumholz, C McKee,
Star cluster formation in turbulent, magnetized dense clumps with radiative and outflow feedback,
Monthly Notices of the Royal Astronomical Society, Volume 439, Issue 4, p.34203438, April 1, 2014
 A Myers, C McKee, A Cunningham, R Klein, M Krumholz,
The Fragmentation of Magnetized, Massive Starforming Cores with Radiative Feedback,
The Astrophysical Journal, Volume 766, Issue 2, article id. 97, April 1, 2013
 PS Li, A Myers, C McKee,
Ambipolar Diffusion Heating in Turbulent Systems,
The Astrophysical Journal, Volume 760, Issue 1, article id. 33, November 1, 2012
 A Myers, M Krumholz, R Klein, C McKee,
Metallicity and the Universality of the Initial Mass Function,
The Astrophysical Journal, Volume 735, Issue 1, article id. 49, 2011
Selected Talks
 Building ExascaleReady Adaptive Mesh Refinement Applications with AMReX,
ECP Annual Meeting, Virtual, 2021
 WarpX: Scalable ParticleinCell Algorithms for Emerging Architectures with AMReX.
SIAM Conference on Computational Science and Engineering, Fort Worth, TX, 2021
 AMReX and applications on GPUs  lessons learned from Summit.
Joint SIAM / CAIMS Annual Meeting, Toronto, Ontario, Canada, 2020
 An overview of particles in AMReX,
SIAM Conference on Parallel Processing, Seattle, Washington, 2020
 Introduction to AMReX  a new framework for blockstructured
adaptive mesh refinement calculations,
Advanced Modelling and Simulation Seminar Series, Nasa Ames Research Center, 2018
 A highorder accurate ParticleinCell method for VlasovPoisson
problems over long time integrations,
Advanced Modelling and Simulation Seminar Series, Nasa Ames Research Center, 2016
 Controlling Numerical Error in ParticleinCell Simulations of Collisionless Dark Matter,
SIAM Conference on Computational Science and Engineering, Salt Lake City, Utah, 2015
 RadiationMagnetohydrodynamic Simulations of Star Formation,
Friday Lunch Time Astrophysics Seminar, UC  Santa Cruz, 2014
 The Fragmentation of HighMass Dense Cores,
Planet and Star Formation Seminar, UC  Berkeley, 2013
Poster Presentations
 M Thevenet, JL Vay, A Almgren, D Amorim, J Bell, A Heubl, R Jambunathan, R Lehe, A Myers, J Park, O Shapoval, W Zhang, L Ge, M Hogan, C Ng, D Grote,
Toward Exascale modeling of Plasma Particle Accelerators on GPU ,
Supercomputing 2019, Denver, CO, 2019
 D Amorim, JL Vay, A Almgren, J Bell, K Gott, A Heubl, R Jambunathan, R Lehe, A Myers, J Park, M Rowan, O Shapoval, M Thevenet, W Zhang, Y Zhao, L Ge, M Hogan, C Ng, D Grote,
WarpX  Efficient modeling of plasmabased accelerators with mesh refinement ,
American Physical Society Division of Plasma Physics Annual Meeting, Fort Lauderdale, FL, 2019
 D Amorim, JL Vay, A Almgren, J Bell, A Heubl, R Jambunathan, R Lehe, A Myers, J Park, O Shapoval, M Thevenet, W Zhang, L Ge, M Hogan, C Ng, D Grote,
WarpX ECP project recent progress ,
International Conference on Numerical Simulation of Plasmas, Sante Fe, NM, 2019
 R Jambunathan, A Myers, D Wilcox, JL Vay, A Almgren, D Amorim, J Bell, K Gott, A Heubl, R Lehe, J Park, M Rowan, O Shapoval, M Thevenet, W Zhang, L Ge, M Hogan,
C Ng, D Grote,
WarpX: Towards Exascale Modelling of Pulsar Magnetospheres ,
Connecting Micro and Macro Scales: Acceleration, Reconnection, and Dissipation in Astrophysical Plasmas,
Kavli Institute for Theoretical Physics, Santa Barbara, CA, 2019
 A Myers, J Bell, A Almgren, V Beckner, J Blaschke, C Chan, M Day, B Friesen, K Gott, D Graves, M Katz, T Nguyen, A Nonaka, M Rosso, S Williams, W Zhang, M Zingale
Overview of AMReX  a new framework for blockstructured adaptive mesh refinement calculations,
SIAM Conference on Computational Science and Engineering, Spokane, WA, 2019
 Y L Lin, A Almgren, B Friesen, A Myers
Performance Study of GPU Offloading via CUDA, OpenACC, and OpenMP in AMReX,
SIAM Conference on Computational Science and Engineering, Spokane, WA, 2019
 D Wilcox, D Kasen, A Almgren, A Myers, W Zhang,
SedonaEx: A Monte Carlo Radiation Transfer Code for Astrophysical Events,
SIAM Conference on Computational Science and Engineering, Spokane, WA, 2019
 K Gott, A Myers, W Zhang,
An Overview of GPU Strategies for Porting AmrexBased Applications to Nextgeneration HPC
Systems,
SIAM Conference on Computational Science and Engineering, Spokane, WA, 2019
 M Thevenet, JL Vay, A Almgren, J Bell, R Lehe, A Myers, J Park, O Shapoval, W Zhang, L Ge, M Hogan, C Ng, D Grote,
WarpX: Toward Exascale modeling of Plasma Particle Accelerators ,
Supercomputing 2018, Dallas, TX, 2018
 A Myers, A Cunningham, R Klein, M Krumholz, C McKee,
Fragmentation of Magnetized, Massive Cores with Radiative Feedback
Star Formation and the Interstellar Medium: ThirtyFive Years Later, Berkeley, CA, 2012
