Parallel MATLAB: Single Program Multiple Data 3pm - 4pm, Friday, June 25 2010 3060 Torgersen Hall Virginia Tech's new Ithaca cluster offers the research community access to parallel MATLAB on up to 64 cores. Interested users need to learn about what kinds of problems can be handled in parallel, how one modifies an existing MATLAB program to express a parallel algorithm, and how such a program is executed. In this lecture, we will present the SPMD command, which implements the "single program multiple data" model, similar to MPI. A single "client" begins executing the program, but the SPMD statement is used to indicate commands that should be carried out in parallel by cooperating workers who have separate memory spaces. We will show several example programs, discuss how to find potential parallelism and how to measure its successful application. We will cover the ways of running a parallel program on your desktop (interactively or indirectly), and how you can set up a link to Ithaca so that you can send jobs there and receive results without leaving your desktop MATLAB session. The slides for this class are available online at "http://people.sc.fsu.edu/~burkardt/presentations/vt_2010_spmd.pdf". Please note that, to make use of parallel MATLAB, your desktop machine must have access to the Parallel Computing Toolbox. This is automatically available as part of the campus-wide concurrent license version of MATLAB; however, it is NOT part of most standalone licences. If you want to try out the direct desktop link to Ithaca, we encourage you to get an account on Ithaca in advance of the class, by going to http://www.arc.vt.edu/index.php, and, under "Services & Support" selecting "User Accounts". Once you have an account, you should also refer to the document "https://portal.arc.vt.edu/matlab/RemoteMatlabSubmission.pdf". If you have trouble with the steps described in this document, you may contact the instructors for advice and help.