OMP-test

CMakeLists.txt

cmake_minimum_required(VERSION 3.6)
project(test-app)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -openmp -fopenmp")

set(SOURCE_FILES main.cpp easylogging++.h)
add_executable(test-app ${SOURCE_FILES})

main.cpp

#include <iostream>
#include <omp.h>
#include "easylogging++.h"

using namespace std;

INITIALIZE_EASYLOGGINGPP

void test_areas() {
    LOG(INFO) << "test_areas";
#pragma omp parallel num_threads(2)
    LOG(INFO) << "test area";
}

void test_private() {
    LOG(INFO) << "test_private";
    int n = 123;
    LOG(INFO) << "n before parallel: " << n;
#pragma omp parallel num_threads(2) private(n)
    {
        LOG(INFO) << "n in parallel (begin): " << n;
        n = omp_get_thread_num();
        LOG(INFO) << "n in parallel (end): " << n;
    }
    LOG(INFO) << "n after parallel: " << n;
}

void test_first_private() {
    LOG(INFO) << "test_first_private";
    int n = 123;
    LOG(INFO) << "n before private: " << n;
#pragma omp parallel num_threads(2) firstprivate(n)
    {
        LOG(INFO) << "n in parallel (begin): " << n;
        n = omp_get_thread_num();
        LOG(INFO) << "n in parallel (end): " << n;
    }
    LOG(INFO) << "n after parallel: " << n;
}

void test_reduction() {
    LOG(INFO) << "test_reduction";
    int count = 0;
#pragma omp parallel num_threads(2) reduction(+:count)
    {
        count++;
        LOG(INFO) << "current count: " << count;
    }
    LOG(INFO) << "total count: " << count;
}

void test_max_values() {
    LOG(INFO) << "test_max_values";
    LOG(INFO) << "max threads: " << omp_get_max_threads();
    LOG(INFO) << "max processors: " << omp_get_num_procs();
}

void test_single_copyprivate() {
    LOG(INFO) << "test_single_copy_private";
    int n;
#pragma omp parallel num_threads(2) private(n)
    {
        n = omp_get_thread_num();
        LOG(INFO) << "n value (begin): " << n;
#pragma omp single copyprivate(n)
        {
            n = 100;
        }
        LOG(INFO) << "n value (end): " << n;
    }
}

void test_for() {
    LOG(INFO) << "test_for";
    int A[10], B[10], C[10], i, n;
    for (i = 0; i < 10; ++i) {
        A[i] = i;
        B[i] = 2 * i;
        C[i] = 0;
    }
#pragma omp parallel num_threads(2) shared(A, B, C) private(i, n)
    {
        n = omp_get_thread_num();
#pragma omp for
        for (i = 0; i < 10; i++) {
            C[i] = A[i] + B[i];
            LOG(INFO) << "Thread " << n << " was added elements " << i;
        }
    }
}

int main(int argc, char* argv[]) {
    START_EASYLOGGINGPP(argc, argv);
    LOG(INFO) << "Starting";
#ifdef _OPENMP
    LOG(INFO) << "OpenMP is supported";
#endif
    double start_time = omp_get_wtime();
    test_areas();
    test_private();
    test_first_private();
    test_reduction();
    test_max_values();
    test_single_copyprivate();
    test_for();
    double end_time = omp_get_wtime();
    double tick = omp_get_wtick();
    LOG(INFO) << "time: " << end_time - start_time;
    LOG(INFO) << "accuracy: " << tick;
    LOG(INFO) << "Quit";
    return 0;
}