int main(int argc, char** argv) {
int array[SIZE];
initialize(array, SIZE);
assert( sequentialSum(array, SIZE) == parallelSum(array, SIZE) );
printf("Sequential and parallel functions produced the same result\n");
return 0;
}
int parallelSum(RAIter begin, RAIter end)
{
// If length is less than 1000, accumulate all the values in range [begin, end)
auto len = end - begin;
if (len < 1000)
return std::accumulate(begin, end, 0);
// Divide and Conquer in parallel
RAIter mid = begin + len / 2;
auto handle = std::async(std::launch::async, parallelSum<RAIter>, mid, end);
int sum = parallelSum(begin, mid);
return sum + handle.get();
}
int main()
{
// Get current time using High resolution clock (C++11)
// Count a duration with the time span between the epoch and tthe time_point (C++11)
auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
// A random number generator based on Mersenne Twister algorithm (C++11)
std::mt19937 mtRand(seed);
// Create a vector with 10000 elements
std::vector<int> v(10000);
// Assign a random number (1 ~ 100)
for (auto& value : v)
value = mtRand() % 100 + 1;
// Print result
std::cout << "The sum is " << parallelSum(v.begin(), v.end()) << std::endl;
return 0;
}
