Introduction

Overview

Questions

• What should I expect to learn from the HPC User module?

Objectives

• Set the basis for learning about High-Performance Computing in Science.

Overview

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In doing computational science it is very common to start a project by writing code on a personal computer. Often as the project proceeds we find that we need more computer resources to complete the science project. This may come in the form of needing more processing power to complete the research in a reasonable time. It may also mean needing more memory to be able to run larger calculations. Or it may just mean needing to do a very large number of smaller jobs that would overwhelm a single computer system.

In these cases where we need to seek out more computational resources, we also need to start understanding the performance aspects of our code. More power is not always the answer, sometimes writing more efficient code can get the job done equally as well.

This HPC User lesson is aimed at scientists who need to use computers to do calculations, and not at computer scientists or computer engineers who need to be experts at programming in a High-Performance Computing environment. This lesson will be aimed at giving an overview of performance concepts to provide a general understanding of how to operate in an HPC environment.

Organization

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The first few chapters concentrate on discussing performance issues at the conceptual level with practical examples. These examples are currently given in Python but it is intended to eventually have the user and instructor choose the language that the examples display in to make it more appropriate to teach this to groups primarily interested in R, C/C++, Fortran, or Matlab too. As the lesson proceeds these same concepts will be used in different ways and with examples in different computer languages to help drill them in.

The middle third of the lesson is a language survey. Even though most scientists may work primarily in a single language, it is important to understand the strengths and weaknesses of alternative languages as well as their own favorite.

The last sections provide overviews of some more advanced topics like working with GPUs to accelerate scientific codes. It may be that some of this will be skipped by your instructor due to time limitations but it is good to have these available for reference purposes.

There are hands-on exercises throughout the lesson where you will be asked to apply some of what you have learned. There are also optional homework assignments available for those who want to challenge themselves outside of the workshop.

Most sections also have website links at the end which provide a means to seek out more information.

Key Points

• The HPC User lesson will help to understand basic concepts affecting performance in programming.