4.1 Assignment 9: GNUParallel and ScalingPlease perform the following steps:
Once you've done this you're ready to get the code for the assignment. From the command line on the GPC, move to your scratch directory, and then type: > git clone /scinet/course/scientific_computing/2015/sc3/homework1
> cd homework1 > source setup > make This will load the needed modules, and make the executable needed for the assignment. The directory homework1 should now contain a program called 'blurppm', and 266 images to be blurred. It is used thus: > ./blurppm INPUTPPM OUTPUTPPM BLURRADIUS NUMBEROFTHREADS Before you start the assignment, perform a simple test. Start by requesting an interactive node from the debug queue: > qsub -I -X -q debug -l nodes=1:ppn=8,walltime=2:00:00 > cd $SCRATCH/homework1 > ./blurppm 001.ppm new001.ppm 30 1 > display 001.ppm & > display new001.ppm & The last two commands should display the original and blurred images. Note that you need an X server running on your local machine for the 'display' command to work correctly. Linux and Mac machines should be fine, though you must ssh into SciNet and GPC with the '-X' or '-Y' flag. Windows machines may have problems. For Windows we recommend using MobaXterm, which comes with a built-in X server. Contact us if you run into trouble and need help. The purpose of the assignment is to do timing tests, and explore how judicious use of threads and GNU parallel can improve throughput. An example of the use of the time command is given below: > time ./blurppm 001.ppm new001.ppm 30 1 real 0m52.900s user 0m52.881s sys 0m0.008s You are interested in the 'real' time.
For both of these assignment parts, make sure you are NOT working on a devel node! Make sure you are working on your own compute node. Either log into an interactive session, as shown above, or submit a submission script to the queue. Part 1:
Part 2:
Submit your scripts, timing data, and comments on the results.
Last Modified: Friday Mar 13, 2015 - 09:37. Revision: 1. Release Date: Thursday Mar 12, 2015 - 14:00.
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