Difference between revisions of "OpenMP in Small Bites/Scoping"
OpenMP in Small Bites/Scoping
Jump to navigation
Jump to search
m (Remove linebreak) |
|||
| (2 intermediate revisions by the same user not shown) | |||
| Line 33: | Line 33: | ||
|type="()"} | |type="()"} | ||
+ Click and submit to see the answer | + Click and submit to see the answer | ||
| − | ||{{Note|'''a: | + | ||{{Note|'''a: private, b: shared, c: reduction, d: private '''<br />'''output: <code>a:0, b:1, c:42</code>'''}} |
</quiz> | </quiz> | ||
{{hidden end}} | {{hidden end}} | ||
Latest revision as of 08:54, 18 January 2021
| Tutorial | |
|---|---|
| Title: | OpenMP in Small Bites |
| Provider: | HPC.NRW
|
| Contact: | tutorials@hpc.nrw |
| Type: | Multi-part video |
| Topic Area: | Programming Paradigms |
| License: | CC-BY-SA |
| Syllabus
| |
| 1. Overview | |
| 2. Worksharing | |
| 3. Data Scoping | |
| 4. False Sharing | |
| 5. Tasking | |
| 6. Tasking and Data Scoping | |
| 7. Tasking and Synchronization | |
| 8. Loops and Tasks | |
| 9. Tasking Example: Sudoku Solver | |
| 10. Task Scheduling | |
| 11. Non-Uniform Memory Access | |
This video provides an overview on managing one of the most challenging parts of OpenMP: Data Scoping. It discusses the differences between private, firstprivate, lastprivate and shared variables and shows how to implement a scalable reduction.
Video
Quiz
1. What is the default data scoping of variable in a parallel region when this variable is declared before a parallel region?
2. What is the data scoping of the variables
a, b, c and d in the following code snippet in the parallel region? What is printed when executing the code? int a = 0;
int b = 23;
int c = -3;
# pragma omp parallel num_threads(2) private(a) reduction(+:c)
{ int d = omp_get_thread_num();
a = 42 + d;
# pragma omp critical
b = 1;
c += a + b;}
c = c / 2;
printf("a=%d, b=%d, c=%d\n", a, b, c)
3. The following code snippet is wrong due to a missing data sharing attribute. How can you fix it?
int i, int s = 0;
# pragma omp parallel for
for (i = 1; i < 100; i++){ s = s + a[i];}