DCA.cxx

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
#include "GPUCommonMath.h"
#include "CommonConstants/MathConstants.h"
#include "ReconstructionDataFormats/DCA.h"
#include <iostream>
 
 
namespace o2
{
namespace dataformats
{
 
float DCA::calcChi2() const
{
  // Estimate the chi2 for DCA
  const auto sdd = mCov[0], sdz = mCov[1], szz = mCov[2], det = sdd * szz - sdz * sdz;
  if (o2::gpu::CAMath::Abs(det) < o2::constants::math::Almost0) {
    return constants::math::VeryBig;
  }
  return (mY * (szz * mY - sdz * mZ) + mZ * (sdd * mZ - mY * sdz)) / det;
}
 
std::ostream& operator<<(std::ostream& os, const o2::dataformats::DCA& d)
{
  // stream itself
  os << "DCA YZ {" << d.getY() << ", " << d.getZ() << "} Cov {" << d.getSigmaY2() << ", " << d.getSigmaYZ() << ", " << d.getSigmaZ2() << "}";
  return os;
}
 
void DCA::print() const
{
  std::cout << *this << '\n';
}
 
} // namespace dataformats
} // namespace o2