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Because many of you have not taken an exam from me before, I am providing a few exam sample questions here for your perusal. Although I have drawn from the material that the exam covers, this set of questions is NOT a study guide. Material that is not represented here may in fact be on the exam (conversely, material that is represented here is not guaranteed to be on the exam). The format of the exam will almost certainly be short answer and/or multiple choice. I expect this will have a tendency to lower the average on the exam, which I will certainly take into account when assigning final grades for the course. 1. A cluster of workstations is most aptly described as a a. shared memory multiprocessor
2. What is the diameter of a hypercube?
3. What is the bisection width of a 4x4 mesh with no wraparound connections?
4. What is the message latency of wormhole routing.
5. Draw and label a hypercube with N-16 PEs.
You write a parallel program to smooth a 256x256 pixel image, where each pixel (a 256-level gray color) is replaced by the average of itself and its 8 nearest neighbors.
6. What is the serial time, expressed in the number of smoothing operations (one smoothing op = calculation needed to calculate one smoothed pixel)
7. Lets say you were to implement it on a 16x16 mesh of PEs such that each PE needed to smooth a 16 pixel x 16 pixel subimage. Each PE would need to receive 4*16 + 4 pixels from its neighboring PEs, so that the edges of the subimage could be smoothed correctly. If one smooting op were equal in time to the time needed to transfer one pixel, what would the parallel time be?
8. What would the efficiency be?
9. Can an omega network perform the permutation (0 1 2 3 4 5 6 7) -> (4 2 7 6 1 0 3 5) in one pass (i.e. with no conflicts) ?
10. Draw an 8-input Benes network, and show the proper switch settings for the following permutation: (0 1 2 3 4 5 6 7) to (3 1 5 2 7 4 0 6).
11. Given a Benes network with x inputs and y switches, whre x is a power of 2. If x is doubled, how many switches will be in the larger Benes network?
12. Name a fundamental difference in process creation models between PVM and MPI.
13. In MPI standard communication mode, when does a blocking send return control to the sending process?
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