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Lattice Quantum Chromodynamics (QCD) with dynamical fermions

Scientific area

Simulations of Lattice QCD with dynamical Wilson, Clover, staggered or overlap fermions.

Short description

The dynQCD code is a highly modular and scalable code that runs efficiently on diverse systems from GPU based clusters to highly scalable architectures such as the BlueGene/Q. It includes a range of different fermion discretizations that can be used in ensemble generation via the Hybrid Monte Carlo (HMC) method as well as in valence calculations. As a novel feature, the code also includes dynamical QED. The HMC element features a range of improved algorithms, such as multiple-timescale integration, improved integrators and the Rational HMC method for single quark flavors, among others. Integrators implemented range from CG, BiCGstab and GMRES to multi-level methods. In the valence sector, improved methods such as All-Mode-Averaging (AMA) are implemented as well.

The code has been carefully optimized for the BlueGene/Q architecture, including assembler-level serial code optimizations, low-level communications based on SPI, and threading using pthreads. It reaches an efficiency of close to 40% of machine peak, with perfect weak scaling at this efficiency: all critical communication operations are nearest-neighbor only and have been implemented in an asynchronous fashion, i.e. no global synchronization is required.


  • 458,752 cores (1,835,008 parallel threads) on on BlueGene/Q

Strong scaling of dynQCD on BlueGene/Q.Strong scaling of dynQCD on BlueGene/Q.

Programming language and model

  • C
  • MPI/OpenMP
  • pthreads/MPI
  • pthreads/SPI

Tested on platforms

  • x86
  • BlueGene/P and BlueGene/Q

Application developers and contact

Stefan Krieg
SimLab Nuclear and Particle Physics
Jülich Supercomputing Centre
Forschungszentrum Jülich GmbH
D-52425 Jülich

Kalman Szabo
Fachbereich C - Physik
Bergische Universität Wuppertal
Gaußstraße 20
D-42119 Wuppertal