Glossary
In daily communication, we tend to abbreviate a lot of terms. It is important to us to make it easy to interact with the WarpX community and thus, this list shall help to clarify often used terms.
Abbreviations
ABLASTR: Accelerated BLAST Recipes, the library inside WarpX to share functionality with other BLAST codes
ALCF: Argonne Leadership Computing Facility, a supercomputing center located near Chicago, IL (USA)
ALS: Advance Light Source, a U.S. Department of Energy scientific user facility at Lawrence Berkeley National Laboratory
AMR: adaptive mesh-refinement
BC: boundary condition (of a simulation)
BCK: Benkler-Chavannes-Kuster method, a stabilization technique for small cells in the electromagnetic solver
BTD: backtransformed diagnosics, a method to collect data for analysis from a boosted frame simulation
CFL: the Courant-Friedrichs-Lewy condition, a numerical parameter for the numerical convergence of PDE solvers
CI: continuous integration, automated tests that we perform before a proposed code-change is accepted; see PR
CPU: central processing unit, we usual mean a socket or generally the host-side of a computer (compared to the accelerator, e.g. GPU)
DOE: The United States Department of Energy, the largest sponsor of national laboratory research in the United States of America
ECP: Exascale Computing Project, a U.S. DOE funding source that supports WarpX development
ECT: Enlarged Cell Technique, an electromagnetic solver with accurate resolution of perfectly conducting embedded boundaries
EB: embedded boundary, boundary conditions inside the simulation box, e.g. following material surfaces
EM: electromagnetic, e.g. EM PIC
ES: electrostatic, e.g. ES PIC
FDTD: Finite-difference time-domain or Yee’s method, a class of grid-based finite-difference field solvers
GPU: originally graphics processing unit, now used for fast general purpose computing (GPGPU); also called (hardware) accelerator
IO: input/output, usually files and/or data
IPO: interprocedural optimization, a collection of compiler optimization techniques that analyze the whole code to avoid duplicate calculations and optimize performance
LDRD: Laboratory Directed Research and Development, a funding program in U.S. DOE laboratories that kick-started ABLASTR development
LPA: laser-plasma acceleration, historically used for laser-electron acceleration
LPI: laser-plasma interaction (often for laser-solid physics) or laser-plasma instability (often in fusion physics), depending on context
LTO: link-time optimization, program optimizations for file-by-file compilation that optimize object files before linking them together to an executable
LWFA: laser-wakefield acceleration (of electrons/leptons)
MR: mesh-refinement
MVA: magnetic-vortex acceleration (of protons/ions)
NERSC: National Energy Research Scientific Computing Center, a supercomputing center located in Berkeley, CA (USA)
NSF: the National Science Foundation, a large public agency in the United States of America, supporting research and education
OLCF: Oak Ridge Leadership Computing Facility, a supercomputing center located in Oak Ridge, TN (USA)
OTP: One-Time-Password; see 2FA
PDE: partial differential equation, an equation which imposes relations between the various partial derivatives of a multivariable function
PIC: particle-in-cell, the method implemented in WarpX
PICMI: Particle-In-Cell Modeling Interface, a standard proposing naming and structure conventions for particle-in-cell simulation input
PICSAR: Particle-In-Cell Scalable Application Resource, a high performance parallelization library intended to help scientists porting their Particle-In-Cell (PIC) codes to next generation of exascale computers
PR: github pull request, a proposed change to the WarpX code base
PSATD: pseudo-spectral analytical time-domain method, a spectral field solver with better numerical properties than FDTD solvers
PWFA: plasma-wakefield acceleration
RPA: radiation-pressure acceleration (of protons/ions), e.g. hole-boring (HB) or light-sail (LS) acceleration
RZ: for the coordinate system
r-z
in cylindrical geometry; we use “RZ” when we refer to quasi-cylindrical geometry, decomposed in azimuthal modes (see details here)SENSEI: Scalable in situ analysis and visualization, light weight framework for in situ data analysis offering access to multiple visualization and analysis backends
TNSA: target-normal sheet acceleration (of protons/ions)
Terms
accelerator: depending on context, either a particle accelerator in physics or a hardware accelerator (e.g. GPU) in computing
AMReX: C++ library for block-structured adaptive mesh-refinement, a primary dependency of WarpX
Ascent: many-core capable flyweight in situ visualization and analysis infrastructure, a visualization backend usable with WarpX data
boosted frame: a Lorentz-boosted frame of reference for a simulation
- evolve: this is a generic term to advance a quantity (same nomenclature in AMReX).
For instance,
WarpX::EvolveE(dt)
advances the electric field for durationdt
,PhysicalParticleContainer::Evolve(...)
does field gather + particle push + current deposition for all particles inPhysicalParticleContainer
, andWarpX::EvolveEM
is the centralWarpX
function that performs 1 PIC iteration.
Frontier: an Exascale supercomputer at OLCF
laser: most of the time, we mean a laser pulse
openPMD: Open Standard for Particle-Mesh Data Files, a community meta-data project for scientific data
Perlmutter: a Berkeley Lab nobel laureate and a Pre-Exascale supercomputer at NERSC
plotfiles: the internal binary format for data files in AMReX
Python: a popular scripted programming language