Abstract: The LSCP workshop focuses on symbolic and numerical methods and simulations, algorithms and tools (software and hardware) for developing and running large-scale computations in physical sciences. Special attention goes to parallelism, scalability and high numerical precision. System architectures are also of interest as long as they are supporting physics-related calculations, such as: massively parallel systems, GPUs, many-integrated-cores, distributed (cluster, grid/cloud) computing, and hybrid systems. Topics this year are from theoretical physics (high energy physics and lattice gauge theory/QCD). The effects of transformations in obtaining numerical results for Feynman loop integrals, and the deployment of a novel architecture to achieve large computational power with low electric power consumption are presented.

Abstract: Pezy-SC processor is a novel new architecture developed by Pezy Computing K. K. that has achieved large computational power with low electric power consumption. It works as an accelerator device similarly to GPGPUs. A programming environment that resembles OpenCL is provided. Using a hybrid parallel system ``Suiren'' installed at KEK, we port and tune a simulation code of lattice QCD, which is computational elementary particle physics based on Monte Carlo method. We offload an iterative solver of a linear equation for a fermion matrix, which is in general the most time consuming part of the lattice QCD simulations. On single and multiple Pezy-SC devices, the sustained performance is measured for the matrix multiplications and a BiCGStab solver. We examine how the data layout affects the performance. The results demonstrate that the Pezy-SC processors provide a feasible environment to perform numerical lattice QCD simulations.

Abstract: We apply and compare results of transformations used to annihilate boundary singularities for multivariate integration over hyper-rectangular and simplicial domains. While classically these transformations are applied with a product trapezoidal rule, we use adaptive methods in the ParInt software package, based on rules of higher polynomial degree for the integration over subdomains. ParInt is layered over the MPI environment (Message Passing Interface) and deploys advanced parallel computation techniques such as load balancing among processes that are distributed over a network of nodes. The message passing is performed in a non-blocking and asynchronous manner, and permits overlapping of computation and communication. Comparisons of computation times using long double vs. double precision confirm that the extended format does not considerably increase the time for long doubles. We further apply the proposed methods to problems arising from self-energy Feynman loop diagrams with massless internal lines, in particular where the corresponding integrand has singularities on the boundaries of the integration domain.