QPACE 2 and Domain Decomposition on the Intel Xeon Phi

We give an overview of QPACE 2, which is a custom-designed supercomputer based on Intel Xeon Phi processors, developed in a collaboration of Regensburg University and Eurotech. We give some general recommendations for how to write high-performance code for the Xeon Phi and then discuss our implementation of a domain-decomposition-based solver and present a number of benchmarks.Comment: plenary talk at Lattice 2014, to appear in the conference proceedings PoS(LATTICE2014), 15 pages, 9 figure

Feynman Diagram Sampling for Quantum Field Theories on the QPACE 2 Supercomputer

This thesis covers the topic of applying the method of Feynman diagram sampling to quantum field theories. The method uses a computer simulation to sample the diagrammatic space obtained in a series expansion. For running large physical simulations powerful computers are required. Therefore, two independent parts are supplied. The first part deals with the method of Feynman diagram sampling. The theoretical background of the method itself is discussed. Additionally, important statistical concepts and the theory of the strong force are introduced. A variety of models to study the applicability of diagrammatic methods are evaluated. The method is then applied to sample the perturbative expansion of the vertex correction. In the end we estimate the value of the anomalous magnetic moment of the electron. The second part describes the QPACE 2 supercomputer by looking at its the architecture and cooling system. Guiding benchmarks of the InfiniBand network are presented. At the core of this part, a collection of best practices and useful programming concepts are outlined, which enables the development of efficient, yet easily portable applications for the QPACE 2 system