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Pretty Efficient Parallel Coulomb Solver

Scientific area

N-body simulations (Coulomb, gravitational, …), beam-plasma interaction, vortex dynamics, gravitational interaction, molecular dynamics simulations.

Short description

PEPC is a tree code for solving the N-body problem. It is not restricted to Coulomb systems but also handles gravitation and hydrodynamics using the vortex method as well as smooth particle hydrodynamics (SPH). PEPC is a non-recursive version of the Barnes-Hut algorithm with a level-by-level approach to both tree construction and traversals. The parallel version is a hybrid MPI/PThreads implementation of the Warren-Salmon 'Hashed Oct-Tree' scheme. The long range interactions are computed using multipole groupings of distant particles to reduce computational effort. The Barnes-Hut algorithm is well suited to dynamic, nonlinear problems and can be combined with multiple-timestep integrators.

Proton 7 + LaserLaser interaction with a foil target and resulting ion acceleration.


  • 458,752 cores (1,668,196 parallel threads) on BlueGene/Q
  • 294,912 cores on BlueGene/P

PEPC Scaling JUQUEENWeak scaling and parallel efficiency of the parallel Barnes-Hut tree code PEPC across the full Blue Gene/Q installation JUQUEEN at JSC.

Programming language and model

  • Fortran2003 & C
  • MPI, pthreads, OpenMP, StarSs

Tested on platforms

  • BlueGene/Q and /P
  • x86
  • ARM

Application developers and contact

Simulation Laboratory Plasma Physics
Jülich Supercomputing Centre
Forschungszentrum Jülich GmbH
52425 Jülich