RooFit::MultiProcess demo - RooFit Users Workshop 2024

demo.cpp

// run on ROOT 6.28+ built with -Droofit_multiprocess=ON
// root -l demo.cpp
// or call `demo(YOUR FAVORITE NUMBER OF CPUS)` inside root

#include "RooWorkspace.h"
#include "RooAbsPdf.h"
#include "RooDataSet.h"
#include "RooMinimizer.h"

void demo(int number_of_workers = 2)
{
    RooWorkspace w = RooWorkspace();
    w.factory("Gaussian::g(x[-5,5],mu[0,-3,3],sigma[1])");
    RooAbsPdf* pdf = w.pdf("g");
    RooAbsData* data = pdf->generate(RooArgSet(*w.var("x")), 10000);

    auto nll = pdf->createNLL(*data, RooFit::ModularL(true));

    RooMinimizer::Config cfg;
    cfg.parallelize = number_of_workers;
    RooMinimizer m(*nll, cfg);

    m.migrad();
}