Programming Parallel Computers

HY 2022–2023

MF1: CPU baseline ★

You need to log in to make submissions.

What you will need to do in this task

Please read the general instructions for this exercise first. Here are the additional instructions specific to this task:

Implement a simple sequential baseline solution. Make sure it works correctly. Do not try to use any form of parallelism yet. You are expected to use a naive algorithm that computes the median separately for each pixel, with a linear-time median-finding algorithm.

What I will try to do with your code

I will first run all kinds of tests to see that your code works correctly. You can try it out locally by running ./grading test, but please note that your code has to compile and work correctly not only on your own computer but also on our machines.

If all is fine, I will run the benchmarks. You can try it out on your own computer by running ./grading benchmark, but of course the precise running time on your own computer might be different from the performance on our grading hardware.

Benchmarks

Name Parameters
benchmarks/1 hx = 10, hy = 10, nx = 100, ny = 100
the input contains 100 × 100 pixels and the window dimensions are 21 × 21 pixels
benchmarks/2 hx = 10, hy = 10, nx = 500, ny = 500
the input contains 500 × 500 pixels and the window dimensions are 21 × 21 pixels
benchmarks/3 hx = 10, hy = 10, nx = 1000, ny = 1000
the input contains 1000 × 1000 pixels and the window dimensions are 21 × 21 pixels
benchmarks/4 hx = 10, hy = 10, nx = 1500, ny = 1500
the input contains 1500 × 1500 pixels and the window dimensions are 21 × 21 pixels

Grading

In this task your submission will be graded using benchmarks/4: the input contains 1500 × 1500 pixels and the window dimensions are 21 × 21 pixels.

The point thresholds are as follows. If you submit your solution no later than on Thursday, 31 August 2023, at 23:59:59 (Helsinki), your score will be:

Running timePoints
≤ 30.000 sec 1
≤ 20.000 sec 2
≤ 15.000 sec 3
≤ 12.000 sec 4
≤ 9.000 sec 5

For late submissions you will not get any points.