#include <iostream>
#include <chrono>
#include <ROOT/RDataFrame.hxx>

int main(int argc, char* argv[])
{
  uint32_t threads=0;
  if(argc==2)
      threads=std::atoi(argv[1]);
  
  ROOT::EnableImplicitMT(threads);

  ROOT::RDataFrame r(100000000);
  auto rr = r.Define("v", [](ULong64_t e) {return pow(1./(e+1),2);}, {"rdfentry_"}).Sum<double>("v");
    
  auto start = std::chrono::high_resolution_clock::now();
  *rr;
  auto finish = std::chrono::high_resolution_clock::now();

  std::chrono::duration<double> elapsed=finish-start;
  
  std::cout << threads << "\t" << elapsed.count() << std::endl;
}