BQCD

Principal Investigator: 

Dr David Brayford (LRZ)
Email: brayford@lrz.de

Dr. Momme Allalen (LRZ)
Email: allalen@lrz.de

Dr. Hinnerk Stueben (Konrad-Zuse-Zentrum fuer Informationstechnik Berlin)
Email: stueben@zib.de

Other application users/developers: 

QCD codes are widely used in many projects like LHC, QPACE, PRACE for research or benchmarking purposes. BQCD, written by Dr. Hinnerk Stueben (Konrad-Zuse-Zentrum für Informationstechnik Berlin) and improved by Dr. Momme Allalen (Leibniz Supercomputing Centre). It supports both pure MPI and hybrid programming model. In addition to being a well-used QCD application in Germany, it is also used in research centres or Universities in Japan, UK, Switzerland, Russia, Mexico and Yemen.

Scientific area: 
Quantum Chromodynamics with dynamical standard Wilson fermions.
Abstract: 
BQCD is a hybrid Monte-Carlo code that simulates Quantum Chromodynamics with dynamical standard Wilson fermions. The computations take place on a four-dimensional regular grid with periodic boundary conditions. The kernel of the program is a standard conjugate gradient solver with even/odd pre-conditioning. Several HPC systems were used to compare the hybrid communication mode of BQCD against the pure MPI.
Scalability: 
Up to the full BG/P 294912 cores. The scalability is also proven up to 131072 cores of SuperMUC (IBM iDATAPLEX cluster @ LRZ).
Versions: 
MPI
OpenMP
Other: 
Original version of the code is a combination of both “hybrid” MPI/OpenMP plus shmem communication. Some of the numerical kernels within BQCD are in the process of being ported to OpenCL.
Tested on platforms: 

BG/L, BG/P, Cray XT4/XT5 and XT6, SGI Altix/UV, ICE Cluster, Tibidabo (ARM prototype system at BSC) and MinoTauro (GPU cluster at BSC).

Images: 
Any other information: 

1. G. Schierholz and H. Stüben,  Optimizing the Hybrid Monte Carlo Algorithm on the Hitachi SR8000, in S. Wagner, W. Hanke, A. Bode and F. Durst, High Performance Computing in Science and Engineering, Munich 2004, Springer-Verlag, pp. 385--393.
2. M. Allalen, M. Brehm and  H. Stüben,  Performance of quantum chromodynamics (QCD) simulations on the SGI Altix 4700, COMPUTATIONAL METHODS IN SCIENCE AND TECHNOLOGY 14(2), 69-75 (2008).
3. http://www.zib.de/stueben/bqcd
4. Stüben, H. and Allalen, M. Extreme Scaling of the BQCD Benchmark, in: Mohr, B. and Frings, W. (eds.), Technical Report FZJ-JSC-IB-2010-03 (2010) 31–34