Chi2BasedCDCPathPairFilter.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#include <tracking/ckf/cdc/filters/pathPairs/BaseCDCPathPairFilter.h>
 
#include <tracking/trackFindingCDC/numerics/Weight.h>
 
namespace Belle2 {
  class Chi2BasedCDCPathPairFilter : public BaseCDCPathPairFilter {
  public:
    TrackFindingCDC::Weight operator()(const BaseCDCPathPairFilter::Object& pair) final
    {
      const auto& lhs = *pair.first;
      const auto& rhs = *pair.second;
 
      if (lhs.size() > rhs.size() + 2) {
        return true;
      } else if (lhs.size() + 2 < rhs.size()) {
        return false;
      }
 
      // Order by chi2 of fit of last state
      return lhs.back().getChi2() < rhs.back().getChi2();
    }
  };
}