Search

link to homepage

Institute for Advanced Simulation (IAS)

Navigation and service


dynQCD

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.

Scalability

  • 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

  • GPUs (NVIDIA)
  • 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
Germany

s.krieg@fz-juelich.de

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

szabo@uni-wuppertal.de


Servicemeu

Homepage