一、 課程背景與目的：

In order to make full use of modern supercomputer systems with multicore/manycore

architectures, hybrid parallel programming with message-passing and multithreading is essential. While MPI is widely used for message-passing, OpenMP for CPU and OpenACC for GPU are the most popular ways for multithreading on multicore/manycore clusters. In this 3-day course, we focus on optimization of single node performance using OpenMP for CPU. We “parallelize” a finite-volume method (FVM) code with Krylov iterative solvers for Poisson’s equation on Oakbridge-CX supercomputer (OBCX) at the University of Tokyo with 6.6 PF peak performance (https://www.cc.u-tokyo.ac.jp/en/supercomputer/obcx/system.php), which consists of the most recent CPU’s (Intel Xeon Platinum 8280 (Cascade Lake, CLX).

 

二、課程之大綱與講者：

In this Summer School, the target application is a 3D FVM code for Poisson’s equation by ICCG Method (Conjugate Gradient (CG) iterative method with Incomplete Cholesky preconditioning), which is widely-used in practical applications. Because ICCG includes “data dependency”, where writing/reading data to/from memory could occur simultaneously, parallelization using OpenMP is not straight forward. We need certain kind of reordering in order to extract parallelism. In this 3-day course, lectures and exercise on the following issues will be provided:

1. Overview of Finite-Volume Method (FVM)

2. Kyrilov Iterative Method, Preconditioning

3. Implementation of the Program

4. Introduction to OpenMP

5. Reordering/Coloring Method

6. Parallel FVM by OpenMP

 

三、課程詳細時間地點以及方式：

August 22, 2020

●Introduction

●Finite Volume Method (FVM)

August 29, 2020

●Introduction to OpenMP

●Reordering

September 5, 2020

●Reordering

●Parallel FVM by OpenMP