56 lines
1.3 KiB
C++
56 lines
1.3 KiB
C++
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#include <iostream>
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#include <omp.h>
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double wasteTime(double in)
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{
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double accum = in;
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for (size_t i=0;i<5000000;i++) {
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accum = accum + accum/2.0 - accum/3.0;
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}
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return accum;
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}
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int main()
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{
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using namespace std;
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cout << "OpenMP test:\n";
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bool run = true;
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int n = 0;
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omp_set_num_threads(8);
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#pragma omp parallel shared(run,n)
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{
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while (run) {
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int myTask;
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double lol = 0.0;
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#pragma omp critical (secA)
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{
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myTask = n;
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n++;
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if (myTask >= 50) run = false;
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if (run) {
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cout << "Thread #" << omp_get_thread_num() << " on task " << myTask << "/1.\n";
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lol -= wasteTime(myTask * 1.0);
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cout << "Thread #" << omp_get_thread_num() << " got " << lol << " on task " << myTask << "/1. Task done.\n";
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}
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}
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if (run) {
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#pragma omp critical (secB)
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{
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cout << "Thread #" << omp_get_thread_num() << " on task " << myTask << "/2.\n";
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lol += wasteTime(myTask * 2.0);
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cout << "Thread #" << omp_get_thread_num() << " got " << lol << " on task " << myTask << "/2. Task done.\n";
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}
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#pragma omp critical (secC)
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{
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cout << "Thread #" << omp_get_thread_num() << " on task " << myTask << "/3.\n";
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lol -= wasteTime(myTask * 3.0);
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cout << "Thread #" << omp_get_thread_num() << " finished task " << myTask << " with the useless result of " << lol << "\n";
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}
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}
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}
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}
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}
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