Undergraduates at the University of Tennessee Do Their Homework on a Supercomputer

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1 Undergraduates from the University of Tennessee spend a few milliseconds with the machine that performs their homework. Photograph by Jayson Hines, Oak Ridge National Laboratory. Undergraduates at the University of Tennessee Do Their Homework on a Supercomputer May 15, 2009 Knoxville, TN Students in the undergraduate Data Structures and Algorithm Analysis class (CS140) at the University of Tennessee have been making waves. The National Institute for Computational Sciences (NICS) provided more than thirty students with special accounts on Kraken, the world s fastest academic supercomputer. Each student installed and ran a hydrodynamics code on the machine, simulating different types of fluid flow. I always heard about supercomputers and that the University of Tennessee has the newest, fastest supercomputer, but I was not sure about what it was, said Safa Noel, a student in the class. After using the supercomputer, I understood its concept and how it works. Kraken, a Cray XT5 supercomputer, contains more than sixty thousand computational cores and performs more than six hundred trillion operations per second. Whatever research I end up doing, I'll probably be doing a lot of work that

2 involves modeling on large systems, said Madison Brandon, a mathematics major from Germantown, Tennessee. Clearly, multi processor programming will be important there. Her classmate, Chris Richardson, agreed. The thing that opened my eyes the most was the way that this is going to be the wave of the future, he explained. There is always going to be a desire for faster and more efficient computing, and this will be it. Multi processor programming is going to be huge in the future. The use of this supercomputer in an undergraduate class combined expertise and equipment at both the university and the nearby Oak Ridge National Laboratory (ORNL), a national research laboratory thirty miles away. This collaboration was made possible by the Joint Institute for Computational Sciences (JICS). Dr. David Banks, one of the university based faculty at JICS, taught the course. JICS is a unique organization. It is the only place in the world where faculty at a flagship university can partner with the staff at a national laboratory in order to teach undergraduates from different departments how to write code and run it on a world class supercomputer. Kraken outperforms an ordinary laptop by a factor of more than a hundred thousand. According to Professor Jack Dongarra, director of the university s Interdisciplinary Graduate Minor in Computational Science (IGMCS). Computational science is an emerging field of study in which mathematical models of climate, biology, chemistry, and physics are translated into computer programs. Executing these programs and analyzing the resulting data has become an important new addition to conventional experimental methods in science. Although there have been other efforts nationwide to introduce students to supercomputers through elective courses for upperclassmen and graduate students, this may be the first time students have used a world class supercomputer in an ordinary introductory course in the undergraduate curriculum. Programming a supercomputer. Kraken is the leading supercomputer within the nationwide TeraGrid. Dr. John Cobb is the principal investigator for the TeraGrid Resource Provider at ORNL and sponsored the initial account that kick started the

3 effort to give the students access to supercomputing. The sophomore level class is taught within the Electrical Engineering and Computer Science (EECS) department and is required for Computer Science majors, although students from other majors enroll as well. No one in the class had any prior experience programming a massively multi processing computer like Kraken, but Drs. Christian Halloy and Kwai Wong from the Joint Institute for Computational Sciences (JICS) introduced them to the basics of distributed programming. With hands on training in their programming labs, students learned how to make Kraken s many processors talk to each other, sending volleys of messages across a high speed network from one node to another. The students analyzed the speed at which an algorithm executes when using different numbers of cores, from tens to thousands. Multi processor programming definitely sets you apart from the competition when applying for any computerrelated job, said sophomore Michael Jugan, a computer engineering major from Knoxville, TN. Making a program run efficiently on multiple processors requires a better understanding of the computer's hardware than regular coding does. Supercomputers have a reputation for being difficult to program, but Anthony Tesone had a different perspective. I actually spent quite a few hours programming on Kraken, he said. I thought it was pretty fun and had a rather simple interface which made it just like programming on my Linux computer.

4 StudentsinCS140walkingbetweenrowsofcomputercabinetsofKrakenandJaguar Spendingqualitytimewiththefastestcomputers.Onthedaybeforefinalexams began, students in the class took time off from their studies to visit ORNL and see the machine they had been using for their homework assignments. Jim Ferguson, director of Education, Outreach and Training for NICS, showed them the machine room;cray sjefflarkinledthemaround,behind,andbetweenkraken seighty eight cabinets. He also showed them the other Cray XT5 that shares the floor, ORNL s Jaguar supercomputer, ranked as the fastest open science machine in the world. Thestudentsworeearplugstomutetheroarofthecomputers coolingfans. Itwas fascinating to me how the supercomputer managed all the information, said student David Prenshaw. It made me realize how much work can be done on a machine such as Kraken. When I was standing and looking at Kraken, I could not helpbutwonderhowmuchdatawaspassingthroughthemachineatthatmoment. Visualizing the results. As part of their homework, students created animated moviestovisualizethedatatheygeneratedonkraken.theyalsoconstructedweb pages,allowingpeopleallovertheworldtoseetheresultsoftheircalculationson thesupercomputer.taylormorris,astudentintheclass,observedthat apictureis worth a thousand words, and a 3D or animated picture on a computer is even

5 better. She added that using computer graphics to explain the research that is going on will be extremely important in the future of computing. Visualization of hydrodynamics simulation on Kraken by students in CS140. Images by Madison Brandon. After the students toured the machine room, they met with Jamison Daniel, a member of ORNL s Scientific Computing group. Daniel demonstrated the 35 millionpixel display wall located one floor above Kraken. The high resolution screen serves as a super sized computer monitor, allowing the results of large scale simulations on Kraken to be viewed in ORNL s high tech, theater style environment. Undergraduate Colin Campbell remarked that computer graphics is essential for transferring the output of code from a format that is recognizable to only a few into a graphical format that is easily understood by the people who need the information.

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7 Students in CS140 observing the 35 million pixel display wall at ORNL. Photograph by Jayson Hines, Oak Ridge National Laboratory. The next generation of programmers. Professor Kevin Tomsovic, head of the EECS department, observed that two great challenges in computer science education today are to excite a new generation about the diverse range of problems we study and to attract top students to our field. Incorporating supercomputing early in the curriculum helps accomplish both." Although programmers themselves are not the primary users of supercomputers like Kraken, Richardson pointed out that with personal computers becoming more powerful and the increasing number of processors, it won t be too long before most all programs will be written to be compatible with multi processors and to take full advantage of the advances in hardware. Fellow student Chris Chomicki added, I greatly enjoyed the experience; the only thing I think could have improved my knowledge of the supercomputer is getting more time to use it. Dr. Phil Andrews, director of NICS, pointed out that even though there are many users of supercomputers, there are not as many people writing software for them. The models for programming a supercomputer are significantly different from those prevalent on more common systems and require a more advanced approach. It is important for the nation's continued leadership in computing that we expose as many students as possible, as early as possible, as often as possible, to programming on these high end platforms."