Parallel STL Test with Intel Parallel Studio 2018

reduce.cpp

#include <cstdlib>
#include <iostream>
#include <vector>
#include <sstream>
#include "pstl/execution"
#include "pstl/algorithm"
#include "pstl/numeric"
#include "pstl/memory"
#include "tbb/task_scheduler_init.h"

int main() {
  // Init TBB Threads
  int pstl_num_threads;
  if (auto pstl_num_threads_ca = std::getenv("PSTL_NUM_THREADS")) {
    std::istringstream iss(pstl_num_threads_ca);
    iss >> pstl_num_threads;
  }
  else {
    pstl_num_threads = tbb::task_scheduler_init::default_num_threads();
  }
  std::cout << "PSTL_NUM_THREADS: " << pstl_num_threads << '\n';
  tbb::task_scheduler_init init(pstl_num_threads);
  
  // 10,000 double vector with 1/2
  std::vector<double> v(1'000'000);
  std::fill(std::execution::par_unseq, v.begin(), v.end(), 0.5);

  // Reduction
  auto result = std::reduce(std::execution::par, v.begin(), v.end(), 0.0);
  std::cout << "Result: " << result << "\n";
  return 0;
}