// OpenMP3.cpp : 定义控制台应用程序的入口点。 // reduction 子句方法进行求和 #include "stdafx.h" #include <omp.h> #include <Windows.h> #include "time.h" #define NUM_THREADS 2 int _tmain(int argc, _TCHAR* argv[]) { clock_t t1 = clock(); omp_set_num_threads(NUM_THREADS); long long sum = 0; #pragma omp parallel for reduction(+:sum) for(long i = 1; i <= 1000000000; i += 1) { sum = sum + i; } clock_t t2 = clock(); printf("sum = %lld ", sum); printf("parallel time = %d ", (t2 - t1)); t1 = clock(); sum = 0; for(long i = 1; i <= 1000000000; i += 1) { sum = sum + i; } t2 = clock(); printf("sum = %lld ", sum); printf("serial time = %d ", (t2 - t1)); system("pause"); return 0; }