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Please read the general instructions for this exercise first. Here are the additional instructions specific to this task:
Port your solution to IS6a to the GPU; again, make it run as fast as possible.
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.
| Name | Parameters | 
|---|---|
| benchmarks/1 | nx = 100, ny = 100 | 
| the input is a structured black-and-white image with 100 × 100 pixels | |
| benchmarks/2a | nx = 199, ny = 199 | 
| the input is a structured black-and-white image with 199 × 199 pixels | |
| benchmarks/2b | nx = 200, ny = 200 | 
| the input is a structured black-and-white image with 200 × 200 pixels | |
| benchmarks/2c | nx = 201, ny = 201 | 
| the input is a structured black-and-white image with 201 × 201 pixels | |
| benchmarks/3 | nx = 400, ny = 400 | 
| the input is a structured black-and-white image with 400 × 400 pixels | |
| benchmarks/4 | nx = 600, ny = 600 | 
| the input is a black-and-white image with 600 × 600 pixels | |
In this task your submission will be graded using benchmarks/4: the input is a black-and-white image with 600 × 600 pixels.
The point thresholds are as follows. If you submit your solution no later than on Wednesday, 03 December 2025, at 23:59:59 (Helsinki), your score will be:
| Running time | Points | 
|---|---|
| ≤ 8.000 sec | 1 | 
| ≤ 5.000 sec | 2 | 
| ≤ 3.000 sec | 3 | 
| ≤ 2.000 sec | 4 | 
| ≤ 1.000 sec | 5 | 
If you submit your solution after the deadline, but before the course ends on Wednesday, 31 December 2025, at 23:59:59 (Helsinki), your score will be:
| Running time | Points | 
|---|---|
| ≤ 5.000 sec | 1 | 
| ≤ 3.000 sec | 2 | 
| ≤ 1.000 sec | 3 | 
Your submissions to this task will also automatically take part in the contest, and you can receive up to 2 additional points if your code is among the fastest solutions this year!
| Running time | Extra points | 
|---|---|
| ≤ 1.20 × fastest | 1 | 
| ≤ 1.05 × fastest | 2 |