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Please read the general instructions for this exercise first. Here are the additional instructions specific to this task:
Using all resources that you have in the CPU, solve the task as fast as possible. You are encouraged to exploit instruction-level parallelism, multithreading, and vector instructions whenever possible, and also to optimize the memory access pattern. In this task, you are permitted to use single-precision floating point numbers.
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 | Operations | Parameters |
|---|---|---|
| benchmarks/1 | 1,004,000,000 | nx = 1000, ny = 1000 |
| the input contains 1000 × 1000 pixels, and the output should contain 1000 × 1000 pixels | ||
| benchmarks/2a | 16,016,000,000 | nx = 1000, ny = 4000 |
| the input contains 4000 × 1000 pixels, and the output should contain 4000 × 4000 pixels | ||
| benchmarks/2b | 16,016,000,000 | nx = 1000, ny = 4000 |
| the input contains 4000 × 1000 pixels, and the output should contain 4000 × 4000 pixels | ||
| benchmarks/2c | 15,991,989,003 | nx = 999, ny = 3999 |
| the input contains 3999 × 999 pixels, and the output should contain 3999 × 3999 pixels | ||
| benchmarks/2d | 16,040,029,005 | nx = 1001, ny = 4001 |
| the input contains 4001 × 1001 pixels, and the output should contain 4001 × 4001 pixels | ||
| benchmarks/3 | 216,144,000,000 | nx = 6000, ny = 6000 |
| the input contains 6000 × 6000 pixels, and the output should contain 6000 × 6000 pixels | ||
| benchmarks/4 | 729,324,000,000 | nx = 9000, ny = 9000 |
| the input contains 9000 × 9000 pixels, and the output should contain 9000 × 9000 pixels | ||
Here “operations” is our rough estimate of how many useful arithmetic operations you will at least need to perform in this benchmark, but of course this will depend on exactly what kind of an algorithm you are using.
In this task your submission will be graded using benchmarks/4: the input contains 9000 × 9000 pixels, and the output should contain 9000 × 9000 pixels.
The point thresholds are as follows. If you submit your solution no later than on Sunday, 09 May 2021, at 23:59:59 (Helsinki), your score will be:
| Running time | Points |
|---|---|
| ≤ 8.000 sec | 1 |
| ≤ 4.500 sec | 2 |
| ≤ 3.000 sec | 3 |
| ≤ 2.200 sec | 4 |
| ≤ 1.500 sec | 5 |
If you submit your solution after the deadline, but before the course ends on Sunday, 30 May 2021, at 23:59:59 (Helsinki), your score will be:
| Running time | Points |
|---|---|
| ≤ 4.000 sec | 1 |
| ≤ 2.500 sec | 2 |
| ≤ 1.500 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 |